hubbell industrial controls, inc.s mc compact static 4922c ... · 3. install resistors. exercise...

HUBBELL

Hubbell Industrial Controls, Inc. 4922cS2MC Compact Static Instruction ManualPublication 189March 1995Reversing Controller

JPS-395-0M © 1995Printed in U.S.A.

Table ofContentsGeneral Control Panel

Static ControlPanel Layout ........... 2

MajorComponents ........... 4

Installation &Adjustment ............. 5

Circuit Description .......... 11

Specifications ....... 12

Adjustable SpeedControl (ASC)Diagrams& Call-Outs .......... 15

Troubleshooting ..... 18

Silicon ControlledRectifier (SCR)Section .....................21

Step Reference BoardSection .....................25

Tach SignalLoss AssemblySection .....................29

HubbellIndustrial

Controls, Inc.a subsidiary of Hubbell Inc.

50 Edwards StreetMadison, Ohio 44057

(216) 428-1161Fax (216) 428-7635

GeneralDescriptionThe Type 4922C StaticReversing Controller is asolid state adjustablespeed motor controller uti-lizing compact unitizedconstruction and providingspeed regulated control ofwound rotor motors. Themotor speed is controlledby varying the motor pri-mary voltage via primarySCR bridges, and the di-rection of motor rotation iscontrolled by selecting theappropriate SCR bridgesfor the commanded func-tion. The adjustable speedcontrol unit varies the SCRbridge firing signals andthe SCR bridge selectionin response to a changingmotor speed reference sig-nal. The retarding torqueduring the reduced speedlowering operation is pro-vided by motor countertorque. The retardingtorque during full speedlowering can be providedby true motor and systemregeneration. Motoring tocounter torque transitionsand vice versa are auto-matic and are controlledby the adjustable speedcontrol unit in response tomotor loading conditions.

Hubbell Compact StaticReversing Controller for Hoists

without Load Brakes

HUBBELLStatic Control Layout 2

Static Control Panel Layout4922C Controller – Hoist Application

RPM SelectJumper (RPM SEL)

This jumper has five posi-tions, and provides thecorrect scaling factor forthe system tachometerbased on the synchronousspeed of the driven motor.

The jumper positions avail-able are: 1800, 1200,900, 720 and 600 rpm

For systems not using a Ta-chometer/OverspeedSwitch assembly, placethe RPM Select jumper inthe corresponding syn-chronous speed positionfor the motor used. If a Ta-chometer/OverspeedSwitch assembly is used,place the RPM Selectjumper in the 1200 rpmposition. This is necessarybecause the incorporatedtachometer is geared for1200 rpm operation atmotor synchronous speed.

Torque SelectJumper (T/L SEL)

This jumper is used to se-lect the limited torque valuesupplied by the motor dur-ing counter-torque andplugging operations. The”HI” position, recom-mended for hoisting appli-cations, limits motor torqueto 200–250% duringcounter torque. The ”MED”position limits torque to150%, and the “ADJ” posi-tion provides an adjustablerange of 50% to 150%.Initially place this jumper inthe ”HI” position.

Plugging/Counter-TorqueRelay Jumper(J10 J9)

This jumper is used to se-lect the operation condi-tions for the external plug-ging/counter torque relay.

The start-up adjustments ofthe 4922C Static ControlController involve settingthe control potentiometersand jumper plugs, verify-ing relay operation andwiring connections. Priorto installing and adjustingthis equipment, it is impor-tant to fully understand theequipment, components,controls and adjustments.

This section will providean understanding of the4922C controller. On thefollowing pages are aflow diagram of primarycomponents, a controlboard with major compo-nents called out, and adetailed view and descrip-tion of the AdjustableSpeed Controller.

AdjustableSpeedControllerFollowing is a descriptionof the adjustments and theirfunctions located on theAdjustable Speed Control-ler. Refer to figure 2 fortheir respective locations.

PermissiveJumper (PERM)

This jumper has two posi-tions. The left position is the“Setup” position and allowsthe ramp circuit adjustmentsto be made without operat-ing the firing circuits. Theright position is the normal”Run” position. In this posi-tion the firing circuit permis-sive signal is active and thefiring circuits will operate.Note: with the jumper inthe “Setup” position, the re-maining control circuit willbe active and holdingbrakes may be releasedwhen direction control com-mands are issued. To pre-vent unintended motion,

disable the brake controlcircuit by removing thebrake circuit fuses.

Ramp SelectJumper(RAMP SEL)

This jumper has two posi-tions. The upper position,“Internal”, is the most com-mon position, and con-nects the internal ramp sig-nal to the speed regulatorcircuit. The lower position,“External”, is used whenthe speed regulator circuitis to operate with an out-side reference signal suchas when two or moredrives are to be speedmatched from a commonramp signal. Unless theapplication involves aspeed matching functionwith two or more drivesoperating in a “Master/Slave” arrangement, placethe Ramp Select jumper inthe “Internal” position.

ASC AdjustableSpeed Control

MS Master Switch

PS Pendent Station

PLC ProgrammableLogic Control

RES Resistor

TCM Tach ContinuityModule

TOS Tach/OverspeedSwitch

TPM Thyristor PowerModule/SCR

Figure 1, Flow Diagram ofPrimary Components

HUBBELLStatic Control Layout 3

4922C Controller – Hoist Application

In the right position,“CNTR”, the relay will op-erate whenever the motoris operating in counter-torque. In the left position,“PLUG”, the relay will op-erate only during a com-manded plugging direc-tion change. Mostapplications will use theright counter torque posi-tion, “CNTR”.

Speed TrimPotentiometerThe Speed Trim Potentiom-eter is used to make fineadjustments in systemspeed. In typical singlemotor applications or inmulti-motor applicationswhere the motors operateindependently, this adjust-ment should be set to the“50” position. In “Master/Slave” speed matchingapplications with the Mas-ter drive set to the “50”position, this adjustment al-lows the “Slave” drive tobe trimmed to match thespeed of the “Master”drive. Initially, set this potto the “50” position.

MinimumSpeedPotentiometerThe Minimum Speed Po-tentiometer sets the mini-mum speed signal level outof the ramp circuit. Typi-cally, this potentiometer isset at the “20” position.

MaximumSpeedPotentiometerThe Maximum Speed Po-tentiometer determines theamount of scaling that isapplied to the input speedreference signal. After theminimum speed signallevel has been set, this ad-justment will set the fullspeed level of the inputspeed reference signal.Typically, this potentiometeris set to the “80” position.

Input OffsetPotentiometerThis potentiometer is usedto remove residual firstpoint master switch or pen-dant speed reference sig-nal arising from a speedreference potentiometerwithout an off-point short-ing band. Initially, this po-tentiometer should be set tothe “35” position.

Ramp TimePotentiometerThe Ramp Time potentiom-eter sets the slope of theoutput ramp signal to thespeed regulator circuit. Theadjustment range is from0.5 seconds at the fullcounterclockwise positionto 10.0 seconds at the fullclockwise “100” position.This adjustment determineshow quickly the ramp out-put signal is allowed to in-crease or decrease. Ini-tially, this potentiometer isset fully counterclockwiseto the “0” position.

Torque LimitSetThis potentiometer sets thevalue of limited motortorque during counter-torque or plugging opera-tions when the torque se-lect jumper, describedabove, is placed in the“ADJ” position. The adjust-ment range is from 50% to150%. Initially, set this po-tentiometer fully clockwiseto the “100” position.

LSR TrimPotentiometerThis adjustment is locateddirectly on the main regu-lator board and sets themotor speed value abovewhich the “LSR” LED willlight, and the LSR relaywill pick up. The pickupadjustment range is 15%at full counterclockwise to35% when fully clockwise.Set this potentiometer midrange for a 25% pickup.

HSR TrimPotentiometerThis adjustment is locateddirectly on the main regu-lator board and sets themotor speed value abovewhich the “HSR” LED willlight, and the HSR relaywill pick up. The pickupadjustment range is 85%at full counterclockwise to100% when fully clock-wise. Set this potentiom-eter fully counterclockwise.

GainPotentiometerThis potentiometer is lo-cated on the main regula-tor board and is used toadjust system stability. Ini-tially, set this potentiometermid range.

NullPotentiometerThis potentiometer is lo-cated on the main regula-tor board and is used toadjust the speed regulatoroffset. This is a factory ad-justment and needs no fur-ther attention. Should thesetting of this potentiom-eter be disturbed, returnthe setting to a mid rangeposition.

Figure 2, Variable SpeedController Adjustments,Pontentiometers, Test Points,Jumpers & LEDs

HUBBELLMajor Components 4

Major Components4922C Controller – Hoist Application

1

2

10

7 164

1 Main Contactor

2 Thyristor Module

3 Main Circuit Breaker

4 Control CircuitDisconnect

5 Control Transformer

6 Tach. ContinuityModule

7 Adjustable SpeedControl Module

8 Secondary Contactor

9 Full Speed Contactor

10 Overload Relays

11 Fuses

12 Brake Relay

13 Step ReferenceBoard (not shown)

14 Main Knife Switch(not shown)

15 Control Knife Switch(not shown)

16 SynchronizingTransformers

Shown is a typical hoist application controller arrangement formotors in the 75–100 hp (460V) range.

Shown is a typical dual hoist application controller ar-rangement for motors in the 40–50 hp (460V) range.

11

88

5

109 8

7

3

11

45 6

12

1

HUBBELLInstallation & Adjustment 5

Installation & Adjustment4922C Controller – Hoist Application

FullSpeedContact

Contacts

PotentiometerAssembly

Terminal 2 Terminal 4

Primary Line LeadsPrior to attempting to fine tune the installation of thisequipment, completely familiarize yourself with all themajor components and adjustments discussed on theprevious pages.

Note: The equipment as shipped from Hubbell’s factoryis fully tested and factory preset. This procedure is forfine tuning the installation. If a particular function or as-pect of this panel is not operating properly, the problemis usually in the field wiring.

Initial Inspection & Installation1. Upon receipt, check each item. If shipping damage

is evident, contact the carrier immediately.

2. Maximum storage temperature should not exceed70°C (158°F). Typical operating ambients shouldnot exceed 55°C (131°F). Minimum ambient tem-perature must not be less than –40°C (–40°F).Avoid contaminated atmospheres.

3. Install resistors. Exercise caution when wiring as theresistor element operates at 375 °C (707°F).

4. Install the master switch(es), pendant and/or radioreceiver.

5. Wire equipment per wiring diagrams. Observe lo-cal code for correct wire size, grounding, etc.

Master Switch, Pendant, and/orRadio Control Setup6. Become familiar with the various wiring connec-

tions coming into the panel. Identify the mainpower leads, master switch leads, “T” & “M” motorleads, overload relays and any control options pro-vided with the system.

7. Remove the cover from the Master Switch, pendant,and/or open the radio control cabinet.

8. Check that all the contacts in the master switch orpendant are free and moving properly. If soequipped, check that the radio control output relaycontacts are closing in the correct sequence.

9. Identify the full speed contacts. Verify that they arethe last to close when the master switch, pendant,and/or radio control transmitter lever is moved tothe last speed point in each direction.

10. The Type 4216 Master Switch is typically suppliedwith a 2kΩ , 0° dead band, center tapped speedreference potentiometer. Check the off-point positionof the Master Switch potentiometer by measuringthe resistance between Terminals 2 and 4 on thepotentiometer assembly. The off-point resistanceshould be 0–5Ω . If this resistance range is notpresent, mechanical adjustment will be needed:

MasterSwitch/TachLeads

Motor PrimaryLeads

MotorSecondaryLeads

SecondaryResistor Leads

HUBBELL

AllenScrew

Installation & Adjustment 6


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AllenScrew(look to theleft for theother one)

a. Use a 3⁄32" allen wrench to slightly loosenthe two allen screws that clamp the poten-tiometer to the potentiometer assembly.

b. While reading the resistance between Ter-minals 2 & 4, carefully rotate the potenti-ometer until an ohmmeter reading of0–5Ω is obtained.

c. Carefully tighten the allen screws andreverify the ohmmeter reading on Termi-nals 2 & 4 of the potentiometer assembly.

11. Type 4211 Master Switches or PBC/WPBC Pen-dant inserts are typically suppled with a single2kΩ , 0° dead band, center tapped belt drivespeed reference potentiometer. Check the off-pointposition of the insert potentiometer by measuringthe resistance between Pins 2 and 4 on the potenti-ometer body. The off-point resistance should be 0–5Ω . If this resistance range is not present, mechani-cal adjustment will be need.

a. Use a 3⁄32" allen wrench to slightly loosenthe circumferential potentiometer clamp.

b. While reading the resistance betweenPins 2 & 4, carefully rotate the potentiom-eter until an ohmmeter reading of 0–5Ω isobtained.

c. Carefully tighten the potentiometer clampand reverify the ohmmeter reading on Pins2 & 4 of the Pendant insert or 4211 Mas-ter Switch potentiometer.

12. For Radio/Pendant or Radio/Cab installations, theremaining start-up instructions should be followedusing the Pendant or Master Switch as the controldevice. At the end of the procedure, the Radio Re-ceiver speed output signal can then be set to matchthe Pendant or Master Switch speed signal. Thisstart-up sequence results in uniform speed rangeperformance for all controlling methods.

Controller Power and Off-PointSequence13. Set the Off-Point Timer (if equipped) for a minimum

time delay.

14. Using a digital voltmeter, check the three phasepower at the Circuit Breaker.

15. Close the Circuit Breaker and then the Control KnifeSwitch. The “Tach Continuity” LED, and either the“Hoist” or “Lower” LED should light up on the Ad-justable Speed Control (ASC) module. If the controlhas a Tach Continuity Module, the LED on this as-sembly should be lit. If these LEDs aren’t lit check/replace the fuses in the Control Knife Switch, checkthe Tachometer wiring and connections, check theOverload Contacts, and check the wiring into theCircuit Breaker.

Type 4211 Master Switch Potentiometer Locations

PBC/WPBC Pendant Potentiometer LocationsAllenScrew

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Full Speed LEDshould not be lit.

Full SpeedContactshould be open.

Controller Speed Reference Setupand Sequence16. Turn off the power by turning off the Circuit Breaker

and Control Knife Switch.

17. Remove the access cover from the ASC. Using adigital voltmeter (DVM) set to read 20VDC, placethe black common meter probe tip into TP8. Placethe red meter probe tip into TP1.

18. Move the “Permissive” jumper from the “RUN” posi-tion to the “SETUP” position.

Note: Holding brakes may be released during theremaining setup procedure. To prevent unintendedmovement, disable the brake control circuit by re-moving the brake circuit fuses.

19. Verify that the “Ramp Select” jumper on the ASC isset “INT” position.

20. Verify that the adjustment potentiometers are set tothe factory initial/typical positions. (see Typical Set-ting table or factory preset label)

21. Close the Circuit Breaker and then the Control KnifeSwitch. The “Tach Continuity” LED should lightagain on ASC.

22. The speed reference voltage from the MasterSwitch or Pendant should be positive for the Hoistdirection and negative for the Lower direction. Se-lect the Lower direction with the Master Switch orPendant. The voltage readings on the DVM shouldbe negative. When the Hoist direction is selected,the voltage should be positive. If the DVM readingsare reversed, reverify and correct the wiring be-tween the 4922C Control Panel and the MasterSwitch/Pendant.

23. Verify the control sequence by operating the MasterSwitch or Pendant. Observe the “Permissive” lightson the ASC and the contactor/relay operation onthe panel. (see Control Sequence table)

The following setup will use Lower commands,therefore, a negative voltage on the digital volt-meter is expected.

24. A typical speed range is 10 to 1 with maximumstepless speed equal to 5.0V, and minimum speedequal to 0.5V.

25. Move the Master Switch or depress the Pendantbutton until first point Lower is obtained. The “Run”,“Permissive”, and “Lower” LEDs should light.

26. The DVM should read –0.5V ±0.05V.

27. Move the Master Switch to the Full Lower positionor completely depress the “Lower” Pendant button.The “Full Speed” LED on the ASC should light.

28. Back off the Master Switch handle or Pendant“Lower” button position until the full speed contactin the Master Switch or Pendant opens. The “FullSpeed” LED on the ASC should go out.

TP Locations

Ramp SelectJumper

PermissiveJumper

VerifyTheseSettings

Typical SettingsPotentiometer SettingSpeed Trim ........... 50Max. Speed ......... 80Input Offset ........... 35Min. Speed .......... 20Ramp Time ............ 0Torque Limit ......... 100

ControlSequence



29. The voltage reading on the DVM should be –5.0V±0.05V.

30. If the readings in Step 26 and Step 29 are not ob-tained proceed with Step 31. If the readings arecorrect, skip to Step 39.

31. Move the Master Switch or depress the Pendantbutton until first point Lower is obtained. The “Run”,“Permissive”, and Lower” LEDs should light.

32. Set the “Min Speed” potentiometer full counterclock-wise. Rotate the “Input Offset” potentiometer on theASC until the DVM reads 0V ±0.05V.

33. Move the Master Switch fully in the Lower directionor depress the Lower pendant button. The “FullSpeed” LED on the ASC should go on.

34. Back off on the handle of the Master Switch or thePendant button from the lower position until the fullspeed contact just opens up. It is very important tomove the handle or the button until the full speedcontact just breaks open. The “Full Speed” LED onthe ASC should be out.

35. Adjust the “Max Speed” potentiometer on the ASCuntil a reading of –4.5V ±0.05V is obtained onthe DVM.

36. Repeat steps 31–35 until no further adjustments arenecessary. Typically, three or four iterations are re-quired to obtain a 0V ±0.05V reading at firstspeed point, and a –4.5V ±0.05V setting at themaximum stepless position.

37. Move the Master Switch handle or depress theLower Pendant button until first point Lower is ob-tained. Rotate the “Min Speed” potentiometerclockwise until a –0.5V ±0.05V reading is ob-tained on the DVM.

38. Move the Master Switch handle or depress theLower Pendant button to the maximum position. TheDVM should read –5.0V ±0.05V.

39. Check the minimum speed and maximum speedpoints in the Hoist direction. Move the MasterSwitch or the Pendant through the various speedpoints in the Hoist direction. The “Lower” LED onthe ASC should go off and the “Hoist” LED shouldcome on.

40. At the first speed point for Hoist direction the DVMshould read +0.5V ±0.05V.

41. At full speed hoist (handle fully in the Hoist position)the “Full Speed” LED on the ASC should be lit.

42. Back off on the handle of the Master Switch fromthe hoist position until the full speed contact on theMaster Switch or Pendant just opens up. The “FullSpeed” LED should go out. The DVM should read+5.0V ±0.05V.

43. Return the Master Switch or the Pendant button tothe Off position. The DVM should read 0.0V.





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Min SpeedPotentiometer

Max SpeedPotentiometer

Min SpeedPotentiometer



Controller Ramp and TachometerSignal Adjustments44. Turn off the power by turning off the Circuit Breaker

and Control Knife Switch.

45. Determine the required system accelerated ramptime required for the application. The “Ramp Time”potentiometer on the ASC can provide times from0.5 seconds (set at 0) to 10 seconds (set at 100).Rotate the “Ramp Time” potentiometer to the de-sired time setting. Hoist applications typically useshort acceleration times of 0.5 to 2.0 seconds forgood response.

46. Determine the relative synchronous speed of the sys-tem tachometer. Move the “RPM Select” jumper onthe ASC to the RPM position corresponding to thetachometer synchronous speed value.

Note: When a Hubbell Tachometer/OverspeedSwitch Assembly is used, the “1200 RPM” positionmust be selected.

47. Set the “T/L Select” jumper on the ASC to “HI”.

48. Move the “Permissive” jumper on the ASC from the“SETUP” position to the “RUN” position. Restore op-eration to the holding brake circuit by reinstallingthe brake circuit fuses.

49. Set the “Plug/Counter Torque” jumper on the ASCto “CNTR” position.

Initial Motor DirectionVerification and Gain Adjustment50. Close the Circuit Breaker and then the Control Knife

Switch. The motor control system will now be ableto operate the motor.

Remember: The following steps are done withthe crane motor energized. Please follow allsafety precautions applicable for operating thecrane system.

51. Check the phase of the power by bumping the mo-tor with the Master Switch or pendant in the Lowerdirection. If the motors turns in the Hoist directionchange the wiring between the motor and the con-troller. Bump the motor again and check the rota-tion. Important — don’t change the Circuit Breakerwiring in the controller to correct phase problems.

52. Assuming that the hook is in the UP position, at-tempt to operate the motor at first point Lower bymoving the Master Switch or by depressing thependant Lower button. The hook should descend atminimum speed. If the motor appears to be runningat full speed, stop the control and reverse the Ta-chometer leads.

53. Turn the “Gain” potentiometer on the ASC to thefully counterclockwise minimum gain position.

54. When the ASC is set at minimum “Gain”, the con-troller will be sluggish to changes in direction. Withtoo much “Gain”, the controller will be quick atspeed changes but could be unstable; bouncingback and forth between directions.

Ramp TimePotentiometer

Ramp SelectJumper

PermissiveJumper

T/L SelectJumper

RPM SelectJumper

Plug/CounterTorqueJumper

GainPotentiometer

HUBBELL

55. Move the Master Switch or Pendant button be-tween minimum and mid-speed positions. Observethe operation of the motor to changes in speed ref-erence. The “Lower” and “Hoist” LEDs shouldchange as the handle is moved and the incandes-cent lights on the ASC circuit boards will change in-tensity.

56. Adjust the “Gain” potentiometer on the ASC so thatwhen the Master Switch or Pendant button ismoved from Hoist to Lower or vice-versa the control-ler changes directions with minimal bouncing be-tween the “Hoist” and “Lower” LEDs on the ASC.When the “Gain” is correctly adjusted, the incan-descent lights on the ASC circuit boards will glowevenly and change smoothly when the handle ismoved on the Master Switch. They will not flickerback and forth. Additionally, the crane motor willproduce a smooth, even running sound when thedirection is changed and will not be sluggish inchanging directions.

LSR and HSR Setup/Adjustment57. Place the black common DVM probe tip into TP8.

Place the red meter probe tip into TP4.

58. Set both the “HSR” and “LSR” potentiometers on theASC fully clockwise.

59. Move the handle on the Master Switch or the Pen-dant button in the Hoist position until the DVMreads +1.2V ±0.05V. Hold the handle at this posi-tion throughout the next adjustment.

60. Adjust the “LSR” potentiometer counterclockwise un-til the “Low Speed” LED on the ASC turns on.

61. Move the handle on the Master Switch or the Pen-dant button in the Hoist direction until the DVMreads +4.8V ±0.05V. Hold the handle at this posi-tion throughout the next adjustment.

62. Adjust the “HSR” potentiometer counterclockwiseuntil the “High Speed” LED on the ASC turns on.

Final Load Test and Off-PointTimer Adjustment63. Now load the hook with a safe working load and

prepare the crane for operation utilizing full safetyoperating rules and standards for this facility.

64. Raise and Lower the load using various speed con-ditions. The motor should continue to operatesmoothly through the speed and direction changes.Final “Gain” adjustment can be made at this timefor smooth acceleration and direction changes.

65. Determine the time required for the control to slow adescending load from full speed to minimum speed.This time will be the “Ramp Time” setting. Set the Off-Point Timer for this slow down time period.

66. Open the Circuit Breaker and then the Control KnifeSwitch. Replace the cover on the Master Switch orPendant. Replace the access cover on the ASC. Thiscompletes the set up of the motor control system.

Installation & Adjustment 10


Incandescent Lights

TP Locations

LSRPotentiometer

Low Speed &High SpeedLEDs

HSRPotentiometer

HUBBELLCircuit Description 11

Circuit Description4922C Controller – Hoist Application

PowerCircuitThe incoming three phasepower, L1, L2, L3 is con-nected to the main circuitbreaker, MCB, and thento the main contactor, M.Power is supplied to theSCR bridges through theoverload relays, 10L, 20L,and 30L, when the powercontacts of M are closed.Current limit resistors areconnected in series withthe power inputs of theLowering SCR bridges.The current limit resistorscontrol SCR fault currentsshould they occur. TheSCR bridge outputs pro-vide adjustable voltagepower to the motor pri-mary windings, T1, T2,T3, through the PowerLimit Switch, LS. The limitswitch transformer, LSXFMR,monitors one of the limitswitch power contacts,and removes power fromthe brake panel should themonitored power contactopen. See Fig. 4 (pg. 13)and Fig. 5 (pg. 14).

ControlCircuitThe three phase powerfrom the main circuitbreaker, MCB, is also con-nected to the control circuitbreaker, CCB. The controlcircuit breaker suppliespower to the synchronizingtransformer, XFMR2, andthe control power trans-former, XFMR1. See Fig. 4and Fig 5. TransformerXFMR2 supplies powerand SCR synchronizing in-formation to the Static Con-trol Assembly, SCA, andthe control power trans-former XFMR1 supplies120V power to the re-maining control circuit.

The 120V control circuitpower from the controltransformer is controlled bythe UV relay located on thetachometer continuity as-sembly, TCA. The functionof the TCA is to verify conti-nuity in the Tachometer/Overspeed Switch circuit.The UV relay will pickupwhen continuity is estab-lished through the tachom-eter circuit and the controlcircuit continuity loop com-posed of the normallyclosed overload contacts,10L, 20L, and 30L. TheSCR bridge over tempera-ture switch, mounted onthe central common SCRbridge, is also included inthe control circuit continuityloop along with 1CR and2CR contacts which arepresent when the Float op-tion is supplied.

The master switch or pen-dant station controls theHoist and Lower Relays,HR and LR, the Off-PointTiming Relay, TR, and theFull Speed Contactor, FS.The brake relay, BR, sup-plies power to the brakepanel and is controlled byHR, LR and the LimitSwitch Transformer. HRand LR also operate theMain Contactor, M,through the controllingMaster Switch or Pendantcontacts. The M Contactorand the initiating direc-tional relay will remain en-ergized when the MasterSwitch or Pendant is re-turned to Off-Point to allowthe motor to slow the loadbefore removing powerand setting the holdingbrake. The Off-Point Tim-ing Relay, TR, and the LowSpeed Relay, LSR, performthis function. Normally,LSR will open at minimumspeed to set the brakeand remove power. How-ever, should a system

problem prevent normalslowdown, the TR contactacts as a backup and re-moves power and sets thebrake after a preset mini-mum time. See Fig. 4.

The Master Switch or Pen-dant also provides a bipo-lar adjustable voltage DCspeed reference signalfrom an internal potentiom-eter. A positive signal rep-resents the hoisting direc-tion, and a negativesignal represents the low-ering direction. In thisway, the Master Switchhandle or Pendant buttondetermines the direction ofmotion and establishes avoltage reference level bywhich motor speed will becontrolled.

Figure 5 shows the addi-tion of the SC contactorwhich is used when the ex-tended slow speed optionis required. During normalspeed hoisting operations,the Low Speed Relay, LSR,will be picked up, and theCounter-Torque Relay, CTR,will remain de-energized.This causes the SCcontactor to close and sup-ply normal 0.1 E⁄l motorsecondary impedance inthe rotor circuit. Duringslow, minimum speed op-erations, when LSR isdropped out, or duringcounter-torque operations,when CTR is picked up,the SC contactor will re-main open, and the ex-tended 0.3 E⁄l secondaryimpedance will be in therotor circuit to reduce slowspeed and counter-torquemotor currents.

Figure 5 also shows theaddition of the Float op-tion components whichare, 1FR, 1CR, 2CR, FTR,and the Float Relay As-sembly. The Float option isused when very slow or

zero speed load positioncontrol is required. TheFloat mode is entered bydepressing and holdingthe Master Switch thumbbutton while the MasterSwitch is in the Off posi-tion. This mode limits thefull travel Master Switchspeed value to ±10% withsmooth load controlthrough zero speed.

ControlCircuit,StaticControlAssemblyThe Static Control Assem-bly, SCA, contains all ofthe control system respon-sible for the speed regula-tion function of the StaticReversing Controller. Thesystem also determines themotor’s operating modeby controlling which set ofSCR bridges is supplyingthe power. The Static Con-trol Assembly receives itsthree phase power fromthe synchronizing trans-former, XFMR2. See Figs.4 and 5 (page 13 &14).This transformer provideslow voltage AC power forthe electronic power sup-ply section and synchro-nizing information for thefiring circuits. See Fig. 3(page 12).

The permissive circuitmonitors the Permissivecommand input from theM contactor coil at the120V AC control powerlevel and converts this sig-nal to an isolated lowlevel signal compatiblewith the electronic system.The permissive circuit alsomonitors a tachometercontinuity signal originat-ing on the TachometerContinuity Assembly. In or-



der for the Static ControlAssembly system to oper-ate, the tachometer conti-nuity signal must bepresent along with thecontrol permissive signalfrom the M contactor cir-cuit. The permissive circuitalso monitors the FullSpeed command input.This input will enable fullspeed regenerative loweroperation.

The ramp circuit receivesthe speed reference signalfrom the Master Switch orPendant potentiometerand conditions the signalsuch that it is allowed tochange only at a presetrate. This function providesfor controlled accelerationand deceleration.

The speed regulator circuitreceives the tachometersignal and compares it tothe system speed refer-ence signal from the rampcircuit. If the system speedis below the speed refer-ence level, the output ofthe speed regulator circuitincreases to provide morephase reference signal viathe directional commandcircuit. This increased sig-nal provides more voltage

SpecificationsInput Power .............................. 230V or 460V, 3 phase,

60 hz

Horsepower Range (at 460V) ....... 5–40 hp (compactconstruction); 50–250 hpwith external SCRs

Speed Range ........................... Typical 10 to 1 with fullspeed ≈ 80% sync.

Speed Regulation ...................... Better than 1%

Control Configuration ................. Static Reversing

Temperature Range .................... -40°F (-40°C) to 131°F(55°C) (typical)-40°F(-40°C) to 158°F(70°C) (electronics)

to the motor via the firingcircuits and consequentlymore motor torque to in-crease system speed. Ifthe system speed is abovethe speed reference level,the speed regulator outputreverses polarity. This ac-tion causes the directionalcommand circuit to issue acounter torque commandto slow the motor. The re-sulting counter torque com-mand signal causes thespeed regulator circuit toprovide a clamped or lim-ited phase reference volt-age to the firing circuits tocontrol motor current andtorque during the slowdown interval.

The directional commandcircuit receives the bipolarspeed error signal and abipolar tachometer signalfrom the speed regulatorcircuit and compares thesesignals to determine theoperational mode of thesystem motor. The direc-tional command circuit is-sues a Hoist command sig-nal to activate the Hoistand Common SCR bridgesvia the delayed directionalpermissive circuit, or aLower command signal to

activate the Lower andCommon SCR bridges in asimilar fashion.

The delayed directionalpermissive circuit receivesthe directional commandsignals from the directionalcommand circuit and gen-erates firing circuit permis-sive signals that are de-layed by 4 1⁄2 cycles ofthe 60 hz line. The delayis inserted in the permis-sive signals to prevent fir-ing circuits that control thepreviously OFF SCRbridges from turning ONbefore the SCR bridgeswhich are currently ONhave stopped conducting.Shoot through faults areprevented by this delay.

The firing circuits receivethe phase reference signaland, along with the syn-chronizing signals from thethree phase synchronizingtransformer and the de-layed permissive signalsfrom the delayed direc-tional permissive circuit,produce the firing or gat-ing signals required by theSCR bridges.

Figure 3 — Static ControlAssembly System Block Dia-gram



Figure 4 — Schematic Dia-gram of Compact PrimaryStatic Reversing Hoist ControlSpeed Regulated with FullSpeed Contactor and Off-Point Counter Torque



Figure 5 — Schematic Dia-gram of Compact PrimaryStatic Reversing Hoist ControlSpeed Regulated with FullSpeed Contactor, ExtendedSlow Speed, and Off-PointCounter Torque and Float

HUBBELL


ASC Diagrams & Call-Outs

TB1 Connector

TB3 Connector

TB2 Connector

Test Points

The Adjustable SpeedControl module is madeup of three circuit boards— Regulator Board, Auxil-iary Firing Board and theMain Primary FiringBoard. They are stackedfrom front to back in thissame order. If access toany of these boards is re-quired during troubleshoot-ing, be careful when re-moving and reinstallingthe ribbon cable assem-blies, paying particular at-tention not to bend thedual in-line connector plugpins.

To the left is explodedview of the ASC modulefor board location andclarity. On the followingtwo pages are graphicrepresentations of thelogic diagram for the ASCmodule. The logic dia-grams expands on the sys-tem block diagram pre-sented earlier, andidentifies system circuitfunction and signal levelsby test points.

TB2 Connector

Main PrimaryFiring Board(Rear)

Incandescent Lights

TB1 Connector

ASC Coverfront view

LEDs 1–10 (seechart below fornumbering)

Adjustable Speed Control 15

RegulatorBoard(Front)

Auxiliary PrimaryFiring Board(Middle) Incandescent Lights

ExplodedAssembly View

LED/Potentiometer Numbers and Function

HUBBELLAdjustable Speed Control Logic Diagram 16


HUBBELLAdjustable Speed Control Logic Diagram 17


HUBBELLTroubleshooting 18

Troubleshooting4922C Controller – Hoist Application

The following section is a trouble shooting section that should locate most common problems. When the instructionsrequire a voltage measurement, a hand held DVM set to the appropriate AC or DC scale should be used.

When the instructions involve a common referenced DC voltage, insert the black common test lead of the digital volt-meter into test point 8, 0V, and measure the indicated test point voltage with the red meter test lead.

When the instructions involve PC board replacement, the adjustment potentiometers, if any, on the replacementboard should be set to the approximate positions indicated on the old board.

Control does not operate, will not respond to command inputs.

No power to controller.Restore power.

Main circuit breaker or control circuit breakerClose circuit breakers. (See Major Components, page 4, for location.)

The UV Relay on the Tach Continuity Assembly (TCA) is not energized.There is power to the control.

There is no control power present from Terminal 3 to Terminal 4 (see figure right) on the TCA.Check the control circuit fuses. Replace if open. (See Major Components, page 4, for location.)Investigate the control circuit for the cause of the fault.

Continuity loop Terminal 1 to Terminal 2 is open.Measure the voltage from Terminal 1 to Terminal 2. The normal voltage should be 0VAC.A 120VAC reading indicates an open condition. Check the following:

a. Normally closed overload relay contacts.b. The thermostat located on the center SCR bridge.

Open tachometer, overspeed switch or tachometer signal wiringMeasure the voltage from Terminal 5 to Terminal 6 on the TCA. A normal reading will be 5V to10VAC. A 120VAC reading indicates an open circuit. Check the Tachometer/Overspeedswitch wiring.

A reading of 0V from Terminal 5 to Terminal 6 of the TCA indicates one of the following:a. No power to the TCA, and/orb. Shorted tachometer or tachometer wiring, and/orc. Faulty TCA.

Control will not respond to command inputs. The UV relay on the TCA is operative.

Defective command input control wiring.Check wiring continuity. Correct Problem. (See Major Components, page 4, for location.)

M contactor not operatingCheck M power contacts. (See Major Components, page 4, for location.) Replace if necessary.

Open contactor coil. Replace coil or complete contactor.

Defective Static Control Assembly.The adjustable speed control unit is not responding to the command inputs. See Troubleshooting,page 19, “The ASC module is not functioning.”

Motor operates but runs at full speed in either direction. No speed control.

Loss of tachometer feedback signal.Monitor the tachometer voltage. If the motor is operating and the voltage is zero:

a. Check the tachometer/overspeed unit. The driving belt may be loose or broken.b. The tachometer/overspeed unit driving coupling may be loose.c. The tachometer may be defective. Replace the tachometer or the tach/overspeed unit.

TCA Terminals andMajor Components

TCA Terminals and Relay Lo-cation. (Outline above, pho-tograph below)

Tach/OverspeedUnit



ASC TP Locations

Look here for info on TP Locations

The Adjustable Speed Control (ASC) module is not functioning.

No control power to the ASC.Carefully check for the presence of 3 phase 460V or 230V on the primary leads of transformerXFMR2. If the proper voltages are not present, restore power.

No tachometer continuity signal from the Tachometer Continuity Assembly (TCA).Set the digital voltmeter to a 20VDC scale. Measure the voltage on TB2–9 on the ASC. The volt-age should read 0V.

a. If the voltage reads +8.5V, the tachometer continuity signal is absent. If the UV relay on theTCA is energized with this condition, the TCA is defective. Replace the TCA.

b. If the voltage reads +8.5V and the UV relay on the TCA is de-energized see Troubleshoot-ing, page 18, “The UV relay on the TCA is not energized…”.

c. If the voltage reads 0V the ASC power supply may be defective. Set the digital voltmeter toread 20VDC. Measure the following test points on the ASC and verify the voltages:

TP8 to TP9 –12VDC to –18VDCTP8 to TP10 –8.5VDC ±0.5VTP8 to TP11 +8.5VDC ±0.5VTP8 to TP12 +12VDC to +18VDC

If any of the voltage readings are incorrect, replace the Main Firing Board.

Control circuit permissive signal is not present.Set the digital voltmeter to read 120VAC. Measure the following AC voltages on the regulatorboard on the ASC (for location see ASC Diagrams page 15):

ASC terminals Raise Off LowerTB1–1 to TB1–2 120V 0V 120V

a. If the above readings are not observed, check the control wiring and correct the problem.b. Check command input control wiring. Correct any problems.c. If the UV relay on the TCA is de-energized see Troubleshooting, page 18, “The UV relay on

the TCA is not energized…”.

Speed reference signal is not present.Read the voltage at TB2–1 to TP8 with the digital voltmeter. The voltage should be positive whenthe Hoist direction is chosen. The output should be approximately 1.0–7.0V for the stepless range,and 8.0V for full speed. The voltage should be negative when the Lower direction is chosen. Thevoltage should be approx. –1.0V to –7.0V for the stepless range, and –8.0V for full speed.

Internal problem with the Static Control Assembly.

Defective 3 phase power transformer XFMR2.Set the digital voltmeter to read 20VAC. Measure the AC voltages from TB1–4 on the Main Fir-ing Board of the ASC to each of the secondary leads of the Transformer XFMR2. (For locationsee ASC Diagrams page 15)

a. TB1–4 to TB1–6 (YEL) 10VAC ±15%b. TB1–4 to TB1–2 (BLU) 10VAC ±15%c. TB1–4 to TB1–3 (RED/WHT) 10VAC ±15%d. TB1–4 to TB1–7 (BLK) 10VAC ±15%e. TB1–4 to TB1–1 (WHT/BLU) 10VAC ±15%f. TB1–4 to TB1–6 (GRA) 10VAC ±15%

If any of the voltage readings are incorrect, replace transformer XFMR2.

Defective Power SupplySet the digital voltmeter to read 20VDC. Measure the indicated test points on the ASC RegulatorBoard and verify the following voltages:

TP8 to TP9 –12VDC to –18VDCTP8 to TP10 –8.5VDC ±0.5VTP8 to TP11 +8.5VDC ±0.5VTP8 to TP12 +12VDC to +18VDC

If any of the voltage readings are incorrect, replace the Main Firing Board.

For specific locations of vari-ous LEDs, Test Points and/orConnections in reference tothe Adjustable Speed Control(ASC) module see page 15,ASC Diagrams & Call Outs.

HUBBELL

Defective Permissive CircuitObserve LED1–LED4 on the Regulator Board of the ASC.

a. LED1 Full Speed Permissive. On only when full speed hoist or regenerative lower is used.b. LED2 should be on with 120VAC from TB1–1 to TB1–2 of the Regulator Board of the ASC.

M contactor should be closed. If this is not true see Troubleshooting, page 19, “Control cir-cuit permissive signal is missing.”

c. LED3 should be on with the Tach Continuity signal present from the TCA and 0V from TB2–9 to TB2–14 of the Regulator Board of the ASC. If this is not true see Troubleshooting,page 18, “No tachometer continuity signal from the TCA.”

d. LED4 should be on when LED2 and LED3 are on. With LED4 on, measure the voltage fromTB3–1 to TP8. Both of these connecitons are on the Regulator Board of the ASC. The voltageshould read +12VDC to +18VDC. The permissive jumper must be in the “RUN” position.

If any of the above conditions are not observed, replace the ASC Regulator Board.

Defective Ramp CircuitMeasure the DC voltage between TP1, Ramp, and TP8, 0V, of the Regulator Board on the ASC.The following voltages should be read:

a. Min. Speed Hoist +0.5Vb. Max. Stepless Hoist +5.0Vc. Max. Speed Hoist +6.5V

The voltage readings will rise and fall slowly. If the above conditions are not observed, check thesetup of the Ramp Circuit. If the circuit fails to setup properly as described earlier in steps 31-38on page 8, the circuit is defective. Replace the Regulator Board on the ASC.

Defective Speed RegulatorMeasure the voltage between TP3, ±Tach, and TP8, 0V, of the Regulator Board on the ASC.The following voltages should be read:

a. –0.5V to –5.0V for a stepless Hoist operation.b. +0.6V to +5.0V for a stepless Lower operation

This is the scaled tachometer signal.

Measure the voltage at TP7, ±Err, and TP8, 0V, of the Regulator Board on the ASC. This signalis the Speed Error signal, and will vary from ±0.5V to ±5.0V depending upon motor load. If themotor is not operational and there is no tachometer feedback signal, any speed reference signalwill cause this error signal to quickly saturate to ±6.0V.

If the output does not vary or remains saturated when the system should beregulating, the speed regulator circuit is probably defective. Replace the ASCRegulator Board.

Defective Directional Command CircuitObserve LED5, LED6, and LED7 on the ASC Regulator Board. LED5 should beon during hoist operations. LED6 should be on during driving lower operations.LED7 should be on during slowdown or counter torque lowering operations. IfLED7 is on continuously during Raise operations or fails to come on duringslowdown or counter torque lowering operations, replace the ASC RegulatorBoard. Note: If the polarity of the tachometer signal is not consistent with theRaise operation, LED7 will be on in both directions. Check tach wiring and re-verse if necessary.

Defective Firing CircuitsObserve the incandescent lights on each of the Firing Circuit boards. The lightsshould vary in brilliance as the drive operates. Three lights at a time should beilluminated, equal in brilliance.

a. 3 lights on the rear Main Firing board will illuminate during Hoist and CounterTorque Lower operations.

b. The 2 lights on the central Aux. Firing board and the central light on the MainFiring board will illuminate during Driving Lower operations.

If the above conditions are not observed, correct the problem or replace the affected board.

Troubleshooting 20


LEDNumbers and Function

ASC CoverRegulatorBoard

AuxiliaryPrimary

Firing Board

Main PrimaryFiring Board

d. Min. Speed Lower –0.5Ve. Max. Stepless Lower –5.0Vf. Max. Speed Lower –6.5V

HUBBELL

Silicon ControlledRectifier

HUBBELLGeneral Description 22

Silicon Controlled RectifiersSection Contents

GeneralDescription .............. 22

GeneralComponents ............ 23

Troubleshooting ........ 24

Silicon Controlled Rectifiers – SCRs

The primary SCR bridge isan SCR/Heat Sink assem-bly with the power SCRsconnected in inverse paral-lel. The function of the SCRbridge is to control theamount of voltage appliedto the motor. The SCR, sili-con controlled rectifier, issimilar to standard rectifiersin that it will allow currentto flow in one directionwhile blocking current inthe reverse direction. How-ever, SCRs will conductcurrent only when turnedON. When two SCRs areconnected as shown acontrollable AC switch orcontact is formed that willcarry current in either direc-tion but only when GATEDON. SCRs can react veryquickly to gating signals,quickly enough to be ableto control portions of halfcycles of standard ACpower. When the gatingor firing signal is presentedto the SCR very late in thehalf cycle, the SCR willblock all of the cycle up tothe time of firing. At thetime the gating signal isapplied, the SCR will turnON and conduct the re-maining portions of the halfcycle to the load.

As the firing signal is pre-sented earlier in the halfcycle, the SCR will conductmore and more of thecycle on to the load. Theextremes will be maximumfiring when the SCR bridgepasses all of the AC poweron to the motor, and lockout, zero firing, when theSCR bridge blocks all ofthe AC power.

In static reversing control-lers, the SCR bridges alsoperform a directional con-trol function as well. Ascan be seen in Figures 4 &5 (on pages 13 & 14),there are five SCR bridges,two Hoist bridges, two

Lower bridges, and oneCommon bridge. When aHoist operation is required,adjustable voltage threephase power is supplied tothe motor via the two Hoistbridges and the Commonbridge. The three phase re-lationship of the appliedmotor power determinesthe direction of developedmotor torque and rotation.

A Lower operation will beperformed in one of twoways depending upon me-chanical losses and theweight of the suspendedload. First, adjustable volt-age power is supplied tothe motor via the twoLower bridges and theCommon bridge to pro-duce a driving lower op-eration. If the loading issuch as to continue to re-quire a driving lowertorque, system will supplylowering adjustable volt-age power to meet thecommanded speed condi-tion. If an overhauling con-dition exists, a counter-torque lowering operationwill occur where the HoistSCR bridges and the Com-mon bridge provide motorpower. True motor andpower system regenerationcan be used, if desired, tolower overhauling loads atfull speed. For this condi-tion, the system turns theLower SCR bridges andthe Common SCR bridgefully on to supply full lower-ing voltage to the motor.

The transition from drivinglower to counter-torquelower is automatic and isdetermined by the me-chanical loading pre-sented to the motor. Fullvoltage regenerative lower-ing will produce loweringspeeds 10% to 15%greater than full load hoist-ing speeds.

HUBBELLMajor Components 23


ThyristorPowerModuleProtectionThyristor power modules(TPM’s) are SCR/SCR, fullwave assemblies avail-able in several horse-power ratings from 10–500 hp in ambients up to140°F (60°C). Each as-sembly is configured asan inverse parallel bridgewith snubbing circuit andvoltage transient protec-tion as shown in the illus-tration. The TPM’s are theunits that control the ap-plied motor voltage on pri-mary thyristor controls.

The snubbing circuit, com-prised of a capacitor anda resistor, is connected inparallel with the SCR’sacross the bridge. Thefunction of the snubbingcircuit is to limit the rate ofrise of applied voltage.Transient voltage protec-tion is provided by ametal oxide varistor,MOV, which is also con-nected in parallel acrossthe bridge. The MOV is anon-linear resistive devicethat will limit or clamp thetransient voltage to a safelevel. The snubbing circuitin conjunction with theMOV provides completetransient voltage protec-tion for the TPM’s.

Major Components

Compact SCRBridge Assemblyfor 40hp (460V) orLess

Thryistor Power Module Protection

External SCR BridgeAssemblies for50hp (460V) orGreater



TroubleshootingInverse parallel SCRbridges control AC powerby providing a method ofadjusting applied voltageas in the case of PrimaryMotor Control. The ACPower is handled on a halfcycle basis by one of twoSCR’s. Refer to the PrimarySCR Bridge figure pro-vided. SCR1 can conductpower on the first half ofthe cycle and SCR2 canconduct during the remain-ing half of the cyclethereby providing bal-anced currents. Ammeterreadings of motor primarycurrents at low motorspeeds should producebalanced readings.

If one of the SCR’s fails toconduct, the controlledpower becomes unbal-anced with a DC compo-nent which can saturatecommon motor loads andlead to higher than normaloperating currents. If oneof the SCR’s becomesshorted, the SCR Bridgesupplies full conduction forthat phase resulting in un-balanced phase voltagesand currents in PrimaryControl.

The operating condition ofan inverse parallel SCRBridge can be determinedeasily with a digital DVM.A simple continuity test canbe performed with thepower removed from themotor circuit. In most Pri-mary Control systems,when the power is re-moved and the directionalor main contactor is open,the SCR Bridge is isolatedand continuity measure-ments can be made di-rectly at the bridge. Ashorted SCR will result in avery low or “Zero” ohmme-ter reading. A good SCRBridge will result in a ohm-

meter reading of 200K to300K ohms.

An open or non-conduct-ing SCR as well as ashorted SCR can also belocated by taking a set ofAC and DC readingsacross each SCR Bridgeand comparing the values.Again, normal readingswill be balanced fromphase to phase with the“odd” reading indicating aproblem. By looking at theSCR Bridge waveforms onthe figures supplied, nor-mal operation is indicatedby equal periods of posi-tive and negative voltage.With the motor operatingat minimum speed, ap-proximately 50% voltagewill be supported acrosseach SCR Bridge, and anAC measurement acrosseach bridge should yieldbalanced voltages. A“Zero” or very low AC volt-age reading indicates ashorted SCR. With theDVM set to read DC, volt-age measurements acrosseach bridge should yield alow DC value indicatingequal periods of positiveand negative voltage. Atypical DC voltage encoun-tered in this measurementwill be less than 10 volts.A reading substantiallyhigher than 10 volts indi-cates unbalanced firing.The unbalanced conditionwill affect the readings onthe remaining two phases,therefore, the highest un-balanced voltage whencompared to the remainingreadings, indicates theproblem phase.

SCR Readings

Connecting a DVM as shown above, test an SCRfor the two conditions listed below. If either of thetest conditions fail the SCR will need to be re-placed.

1. Power Off ConditionSet the DVM to Ohms and measure the resistanceacross the SCR. It should read 200k–300kΩ . If itreads 0Ω , then the SCR is shor ted. It needs to bereplaced.

2. Power On Condition (Motor Running at minimum speed)

Set the DVM to read 600VAC. If the DVM readsbetween ≈ 200–300VAC for a 460V system con-figuration, the SCR is acting normal with all phasesbalanced. If the DVM reads 0V, the SCR isshorted. It needs to be replaced.

Now set the DVM to 600VDC. If the DVM read±5 to ±10VDC, the SCR is runing normally with allphases balanced. If the DVM reads >±20VDC,the SCR is conducting current as a diode or is notfiring. It needs to be replaced.

HUBBELL

Step ReferenceBoard

HUBBELLGeneral Discription 26

Step Reference BoardGeneralDescriptionThe 48978-101 and-102 Step ReferenceBoard assemblies providea means of supplying astepped adjustable speedreference signal for adjust-able speed drives from in-put control devices suchas relay output program-mable controllers, orpushbuttons and masterswitches without signal po-tentiometers. Input relaysoperating from the120VAC control powerare activated by the con-trol device contacts andprovide signal isolation.Each selected speed pointis independently adjust-able by one of five poten-tiometers. The -101 as-sembly is used for systemsrequiring a positive speedreference signal for bothdirections, and the -102assembly is used for sys-tems requiring a bi-polarspeed signal.

ApplicationInformationThe 48978-101 & -102Step Reference Board isused to provide individu-ally adjustable speed ref-erence points for adjust-able speed drives fromcontrolling devices notpossessing adjustable volt-age output capabilities.Devices such as program-mable controllers with re-lay only outputs, and mas-ter switches and pendantswithout signal potentiom-eters can control the StepReference Board. The con-trol inputs consist of120VAC relays.

A standard progressivemaintained control se-

quence is required forproper operation of theStep Reference board.The first speed point levelsignal from P1 is availableat the Step ReferenceBoard Reference outputterminal as soon as theFWD or REV directionalrelay is closed. The sec-ond speed point level sig-nal from P2 is availablewhen the 2nd speed relayis closed. The standardprogressive sequence pro-ceeds in this mannerthrough the fifth speedpoint and P5.

The test points on the StepReference Board can beused to set and monitorthe individual speed pointlevels, or the output of theadjustable speed driveramp circuit can be moni-tored as in standard set-upprocedures. In either case,to simplify the system ad-justments, it is recom-mended to set the adjust-able speed driveMinimum Speed Potenti-ometer to a fully counter-clockwise position, andthe Maximum Speed Po-tentiometer to a fully clock-wise position. These ad-justments permit the StepReference Board signals todirectly determine systemspeed level without offsetor scaling.

A typical Step ReferenceBoard application will usethe first four speed pointsas stepless points, and thefifth point as a full speedpoint. The above righttable shows speed levelsrecommended by speedstep.

To insure that the adjust-able speed drive input cir-cuit loading on the StepReference Board potenti-ometers is accounted for,

make the above settingswith the individual speedpoints selected with thecontrol device. The signallevels listed above canalso be monitored at theadjustable speed driveramp output. An alternate

Section Contents

General Description .. 25

Application Info. ....... 25

Circuit Description ..... 26

Specifications .......... 26

Diagrams ................ 27

Step Reference Board

method is to set the speedpoint potentiometers to theapproximate dial positionslisted above, then customadjust the individual signallevels if necessary with thedrive system operational.

Recommend Speed Levels

Speed Test Signal DialPoint Point† Level§ Setting

1st TP1 0.5VDC 102nd TP2 2.0VDC 303rd TP3 3.5VDC 554th TP4 5.0VDC 805th TP5 6.3VDC 100

† The black, common, lead of the digital voltmeter is attachedto TP6, 0V and the red, power, lead is attached to the appro-priate test point.

§ Signal level is either (+) or (–) voltages depending onwhether the speed point being measured is in the Hoist orLower direction.



CircuitDescriptionThe Step Reference Boardassembly is comprised ofsix isolating control relaysand indicating LED’s, andfive speed point adjust-ment potentiometers. SeeFigures R1 and R2. Thereare two directional relays,FCR and RCR that connectthe adjustable speed drivepower supply voltages tothe speed point potentiom-eters. For systems requiringonly a positive speed refer-ence signal, the -101 as-sembly is used, andjumper J1 is in place. Thisjumper causes a commonpolarity supply voltage tobe connected to the speedpoint potentiometers wheneither directional relay isclosed. The -102 assem-bly is used for systems re-quiring a bi-polar speedreference signal, andjumper J1 is removed. Thisversion causes a positivesupply voltage to be con-nected to the speed pointpotentiometers when direc-tional relay RCR is closed,and a negative supply volt-age to be connected tothese potentiometers whendirectional relay FCR isclosed.

Resistors R1 and R2 pro-vide current limit protectionfor the adjustable speeddrive power supply. Theresistive elements of thespeed point potentiom-eters are all connected inparallel. When a direc-tional relay is closed, thevoltage on the wiper ofthe first point potentiom-eter, P1, is connected tothe reference output termi-nal through a normallyclosed 2nd point relaycontact. The setting of thispotentiometer thus deter-mines the first point speedreference signal. Whenthe 2nd speed point relayis energized by a pro-

grammable controller, pen-dant or master switch con-tact closure, the first speedpoint potentiometer, P1, isdisconnected, and the2nd speed point potenti-ometer, P2, is connectedto the reference outputthrough a normally closed3rd point relay contactand a normally open 2ndpoint relay contact. A stan-dard progressive main-tained input sequence isrequired for the steppedoperation to continuethrough the fifth speedpoint.

The voltage setting of eachpotentiometer can be mea-sured on the Step Refer-ence board by means oftest points. A common testpoint, TP6 is provided for0V power supply connec-tion. TP1 through TP5 pro-vide the respective speedpoint voltages. The volt-ages at these points should

SpecifcationsInput Power and Signals

Input relay control voltage .... 120VAC @ 1.3 VAMax.

Reference supply voltage ..... ±24VDC Max.

Loading toReference supply ............... 1.3 KΩ

Reference signal output capabilities

Output stepreference voltage ............... 0 to 75% of Reference

Output impedanceper step ........................... 2.5 KΩ Max.

Output relay contact capabilities

Max resistive switching voltage AC current .................... 250VAC DC current .................... 30VDC

Max resistive switching current AC current .................... 2 amps DC current .................... 3 amps

Temperature range ............. –40°F (–40°C) to122°F (50°C)

Indicators/Diagnostics

LED’s ............................... FWD and REV direc-tion for 2nd, 3rd, 4th,and 5th speed points

Test Points ........................ TP1, TP2, TP3, TP4,and TP5 individualspeed points with TP6for 0V reference

be measured and adjustedonly when the respectivespeed point is selected, asthe external circuit of theadjustable speed drive willload the individual potenti-ometers and change thelevel somewhat when se-lected.

Additional directional re-lay contacts are providedfor auxiliary control func-tions if needed. Two nor-mally closed contacts, onefrom each directional re-lay, are connected in se-ries thus providing anOff-Point LV initializationcircuit. Two normally opencontacts, one from eachdirectional relay are con-nected in parallel and pro-vide a brake relay or mainrelay control circuit. Anadditional normally opencontact from each direc-tional relay is also pro-vided for auxiliary controlfunctions.

Figure R1 – Step Reference Board Outline

HUBBELLDiagrams 28


Figure R2 – Step Reference Schematic

HUBBELL

Tachometer SignalLoss Assembly

HUBBELLGeneral Discription 30

Tach Signal Loss Assy.

49232-101 Tachometer Signal Loss Assembly

GeneralDiscriptionThe 49232-101 & -102Tachometer Signal Loss As-sembly monitors a speedregulated system’s DC ta-chometer signal and com-pares this signal with thesystem’s commandingspeed reference. A speeddifference error signal isproduced and comparedto an adjustable differentialwindow. If the speed differ-ence signal falls outsidethe differential window forlonger than an adjustabletime limit, the unit’s LowVoltage relay will deener-gize. The Low Voltage re-lay will deener-gize imme-diately if the absolute valueof the monitored tachom-eter signal exceeds 125%of the selected synchro-nous speed, thus providinga fixed overspeed sensingfunction.

The Tachometer SignalLoss Assembly can monitor50V or 100VDC tachom-eters, can be set for stan-dard 60 hz synchronousmotor speeds from 600–1800 rpm, can be set toaccept bipolar or positiveonly speed reference sig-nals of up to 50V in mag-nitude, and provides ad-justments for DifferentialError, Error Time, andSpeed Reference SignalAttenuation.

There are two signal levelLockout Command inputsand one 120VAC controlcircuit Isolated LockoutCommand input. These in-puts are used to overridethe unit’s comparison func-tion during periods ofnonspeed regulated op-eration such as Full Speedregenerative lowering ortorque/current limiting re-

versing plugging. Thelockout inputs do not dis-able the overspeed sens-ing function.

ApplicationInformationThe 49232-101 & -102Tachometer Signal Loss As-sembly can be used tomonitor and verify thespeed feedback signal ofspeed regulated controlsystems. The -101 assem-bly will monitor 50V ta-chometers and the -102assembly will monitor100V tachometers. Theassemblies can be set forany of five standard60 hz synchronous ta-chometer speed ranges,and to accept either bipo-lar, ±Ref, or positive only,+Ref, system speed refer-ence signals. The assem-blies also provide immedi-ate detection of overspeedconditions. This functionwill respond to tachometersignal levels exceeding125% of the selectedspeed range.

The assemblies have threeadjustment potentiometers:

1. The Reference Attenu-ation potentiometerallows the systemspeed reference sig-nal to be adjustedand scaled to matchthe speed feedbacksignal requirements.

2. The Differential Poten-tiometer sets thespeed reference errorwindow and deter-mines how precisethe speed must followthe system reference.

3. The Time Potentiom-eter sets the time pe-riod that a sensedspeed tracking error

must exist before theoutput LV relay isdeenergized. Thetime delay function isbypassed when anoverspeed conditionis sensed, causingthe LV relay to disen-gage immediately.

The assemblies have twosignal level Lockout inputs,and one control circuit Iso-lated Lockout input. Theseinputs can be used to in-hibit the speed trackingfunction. When any ofthese inputs are activated,the output LV relay will re-main energized regardless

Section Contents

General Description .. 30

Application Info. ....... 30

Specifications .......... 31

Adjusting TSLA ......... 33

Troubleshooting ........ 34

Tachometer Signal Loss Assembly

HUBBELL

of the speed to referenceerror. Overspeed detec-tion is not inhibited by theactivation of any of thelockout inputs.

The assemblies have aTach Loss Output signal.This current sinking outputcan be connected to 0Vreferenced circuits andused to confirm to thespeed controlling systemthat the motor and tachom-eter are tracking the sys-tem speed reference sig-nal within the set differen-tial limits. This output canalso be used to control anexternal relay. Note: afree-wheeling diode mustbe placed in parallel withthe coil of the external re-lay. This output can sink200 mA to 0V at 70°C.

Figures T2 (on the nextpage) shows a typicalhoist control application ofthe Tachometer Signal LossAssembly. The LV relay onthe assembly is used asthe system low voltage re-lay. The 120V control volt-age is connected to TB1-1,2 and to TB1-3,4. AnyLV circuit permissive con-tacts such as overload orthermostat contacts areconnected in series be-tween TB1-5,6 and TB1-7,8. For standard Off-Point reset operation, theOff-Point setup circuitneeds to be in place.

This is done by jumperingTB2-5,6 and TB2-3,4,and connecting the Off-Point initiating contacts be-tween TB1-1,2 and TB2-5,6. This completes the120V control circuit con-nections for the LV relay.

The motor control systemthat the Tachometer SignalLoss Assembly is monitor-ing, supplies the regulatedDC power for the unit’selectronics. The 0V con-nection is made to TB3-1.The +8.0 to +12.0VDCpower is connected to

TB3-4, and the –8.0 to–12.0V power is con-nected to TB3-3.

The Tachometer Loss out-put, TB3-2, can be con-nected to the TachometerContinuity input on theSpeed Regulating system.This signal provides a di-rect input to the SpeedRegulating system’s Permis-sive circuit. Should this con-nection not be desired, theTach Loss output can be leftopen, but the tachometercontinuity input on thespeed regulating controlshould be jumpered to 0Vto enable the permissivecircuit. The latter is the typi-cal connection.

The speed regulatingcontrol’s Ramp signal isused as the comparisonreference for the moni-tored tachometer signal.The Ramp signal from thespeed control is con-nected to TB3-5.

The system tachometer isconnected to TB3-8 and

Aplication Information 31


SpecificationsInput Power and Signals

LV Control Circuit ............... 120V AC

Signal Circuit Power Supply . 30 mA. loading;±8.0VDC to±12.0VDC

Tachometer Signal

–101 assembly ................. 50V/1000 rpm

–102 assembly. ................ 100V/1000 rpm

System Speed Reference ..... up to 50VDC

Lockouts #1 and #2 ........... connect to + Supply10K ohm load to 0V

Isolated Lockout ................. 10 mA loading @120VAC

OutputTach Loss Out ................... 200 mA sink to 0V

from +Supply @ 70°C

LV Relay ........................... 2 – N.O. @ 10 amps,120VAC @ 70°C

AdjustmentsRPM Select (rpm) (JP1) ......... 600, 720, 900,

1200, 1800

Reference Select (JP2) ......... ±Ref, +Ref

Reference Atten (P1) ........... input reference signalscaling

Differential (P2) .................. 5% – 100%

Time Delay (P3) ................. 0.25–5.0 seconds

Indicators / DiagnosticsLED1............................... Isolated Lockout active

LED2............................... LV Relay engaged

Test Point 1 (TP1) ............... Scaled speed ref.±5.0V System SyncSpeed

Test Point 2 (TP2) ............... Scaled ±Tach; ±5.0Vfor System SyncSpeed; ±6.25V forOverspeed level

Test Point 3 (TP3) ............... –|Tach|; –5.0V for Sys-tem Sync Speed;–6.25V for Overspeedlevel

Test Point 4 (TP4) ............... ±Error; ±5.0V for trip@ set differential

Test Point 5 (TP5) ............... –|Error|; –5.0V for trip@ set differential

Test Point 6 (TP6) ............... 0V

Temperature Range ............ –4°F (–20°C) to158°F (70°C)

TB3-9. The polarity of thetachometer signal is impor-tant when the speed con-trol Ramp signal is bipolar.For typical applications,the positive tachometerline is connected to TB3-9for the Raise or Hoist mo-tion when a positivespeed reference Ramp sig-nal is present at TB3-5.

The Isolated Lockout inputis used to disable thespeed tracking function ofthe Tachometer Signal LossAssembly. The trackingfunction should be dis-abled at any time that thespeed control system is notactively providing speedcontrol operation, such asfull speed, full voltageRaise or Hoist, full voltageregenerative lower, or pro-longed current limit opera-tion during a stalled floatsequence. The IsolatedLockout is activated bysupplying 120VAC fromTB2-1,2 to TB1-3, 4

Figure T1 – Ouline drawing of TSLA

HUBBELLAplication Information 32


Figure T2 – a typical TSLA in-stallation for a hoist controller

HUBBELL

Adjusting TSLA

Adjusting TSLA 33

The jumpers and potenti-ometers on the TachometerSignal Loss Assembly mustbe setup correctly forproper operation of theunit. Below are the majoradjustments and each oftheir respective functions.Adjust them or select themin the following order:

1. RPM Select

2. Ref Select

3. Reference AttenuationPotentiometer

4. DifferentialPotentiometer

5. Time Potentiometer


Differential PotentiometerThis potentiometer sets the speed error comparison window. The adjust-ment range is 5% at the fully counter-clockwise position to 100% at thefully clockwise position. A typical setting would be “15” or “20” for a20% to 25% differential range. This setting can be adjusted to meetthe speed tracking requirements of the system.

Time PotentiometerThis potentiometer sets the Tachometer Signal Loss Assembly responsetime to an error condition. The adjustment range is 0.25 secondswhen the Time potentiometer is set fully counterclockwise to approxi-mately 5.0 seconds for a fully clockwise adjustment. A typical settingwould be “10” or “20” for a 0.5 second to 1.0 second responsetime. The time delay function is used to prevent nuisance trips due tonormal system speed overshoots or undershoots. This setting can alsobe adjusted to meet the speed tracking requirements of the system.

ReferenceAttenuationPotentiometerThis potentiometer is used toscale the speed regulatingsystem’s speed reference Rampsignal to match the scaled Ta-chometer signal. The attenuatedspeed reference signal can bemeasured from TP1 to TP6. Avalue of ±5.0V at this point rep-resents system synchronousspeed. During drive setup, whena system Ramp signal which rep-resents synchronous speed ispresent, adjust the Reference At-tenuation potentiometer for 5.0Vat TP1. With standard HubbellSCR adjustable speed drives, thispotentiometer can be preset to“80”. When the speed controlsystem is operational, operatethe motor at a reduced speedpoint while monitoring the speederror voltage at TP4. When themotor is operating at a constantreduced speed under control ofthe adjustable speed control, ad-just the Reference Attenuation po-tentiometer for a near 0V readingat TP4.

Ref. SelectThis jumper determines whether abipolar or positive only systemRamp signal will be used as thespeed reference. For speed regu-lating systems having a bipolarRamp signal, such as 4922Cand 4929C, this jumper must beset in the ±Ref position. For speedregulating systems with positiveonly Ramp signals, such as4924C and 4925C, set thejumper to the +Ref position.

RPM SelectThis jumper should be set to therpm value that the system tachom-eter turns when the controlled mo-tor is running at it’s synchronousspeed. In direct tachometer tomotor connection, this setting willbe the motor’s synchronousspeed. In applications involvinga Hubbell Tachometer/Over-speed switch assembly, verify thetachometer speed increase/re-duction. Most Tachometer/Over-speed assemblies drive the ta-chometer at 1200 rpm when thesystem motor is running at syn-chronous speed. In these cases,set the jumper to the 1200 rpmposition.

HUBBELLTroubleshooting. 34


TroubleshootingThe function of the Ta-chometer Signal Loss As-sembly is to compare thespeed regulated system’stachometer speed feed-back signal to the systemspeed reference signal. Innormal speed regulatedoperation, these two sig-nals should track due tothe controlling action ofthe speed regulator. If aproblem should developwith the tachometer feedback system, such as abroken or loose coupling,broken drive belt, or opentachometer signal circuit,the Tachometer Signal LossAssembly will deenergizethe LV relay on the assem-bly. A problem with thespeed regulating controlsystem that would causethe system speed not totrack the speed referencesignal will also cause theunit to deenergize theLV relay.

Verify theSetupVerify the setup of the Ta-chometer Signal Loss As-sembly by following theset-up procedure outlinedin the Adjusting Tachom-eter Signal Loss Assemblysection.

Unit PowerFor proper operation ofthe unit, 120VAC must bepresent. This is indicatedby having

1. 120VAC at terminalsTB1-1,2 to TB1-3,4

2. DC control power inthe range of +8.0 to+12.0V must bepresent at TB3-4 toTB3-1, and –8.0 to–12.0V must bepresent at TB3-3 toTB 3-1.

LV RelayDoesn’tEnergizeIn order for the LV relay topick-up, the unit must bepowered as describedabove, the Off-Point resetcircuit must be in place,and the overload/thermo-stat circuit must be com-plete. The Off-Point resetcircuit connects TB1-1,2 toTB2-5,6. TB2-5,6 must bejumpered to TB2-3,4 forproper Off-Point reset op-eration. The overload/ther-mostat circuit connectsTB1-5,6 to TB1-7,8. Verifythe operation and functionof these controlling circuits.

LV Relay isEnergized atOff-Point butDrops OutIf the LV relay is energizedat Off-Point but drops outwhen presence of the con-trolled motion is started,verify the tachometer sig-nal at TB3-8 to TB3-9. Forhoisting applications witha positive hoisting speedreference signal, the ta-chometer signal should bepositive on TB3-9. Alsoverify the presence ofvalid speed reference sig-nal from the speed regulat-ing system. This signalshould be present on TB3-5 to TB3-1 (0V).

Check theposition of theRPM Selectjumper.This jumper must be set toa speed value correspond-ing to the tachometer’sdriven speed at themotor’s synchronousspeed. This adjustment al-lows for discrete gearingor belt reduction ratios.Check the position of theReference Select Jumper.This jumper must be set tocorrespond with the typeof system speed referencesupplied from the speedregulator. Systems such asthe 4922C and 4929Cuse a bipolar speed refer-ence signal. For these sys-tems the Reference SelectJumper must be set to the±Ref. position. For systemswith a positive only speedreference, such as the4925C, the Reference Se-lect Jumper must be set tothe +Ref position.

Look Here forConnection TB1



Shown installed inside a panel.

hubbell industrial controls, inc.s mc compact static 4922c ... · 3. install resistors. exercise...

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