203.743.6741 • 203.798.7313www.preferred-mfg.com

Controllers and Actuators

Catalog 25

Controllers &

Actuators

297

• Danfoss VLT Variable Speed Drive (VSD)• Substantial Electrical Energy Savings - compensates

for oversized fans, oversized motors, partiallyloaded boilers and helps minimize damper losses.

• NEMA 12 Packaging - for worry free boiler roominstallation

• Built in “DC Link” Line Reactor - for reducedelectrical system total harmonics distortion (THD)

• “Soft Turn On” IGBT Transistors - for reduced motorstress (insulation failure)

• Accepts “STEP” Speed Increase from 0 to 100%without tripping - the drive automatically limits therate of fan speed increase to that which will preventan over-current trip

• Full Combustion System Interface – 4-20 mAdcdemand input, 4-20 mAdc feedback and VSDRunning and No Fault Contacts

DescriptionUtilitySaver and Combustion Control Systems use Variable Speed Drives to provide variable speed fan combustion air flow control. Fan speed control minimizes damper pressure drop related to fan power usage. Variable speed fan control is a proven electrical energy savings technique that has been applied to thousands of HVAC installations.

SpecificationsEnclosure: NEMA 12Humidity: 95% non-condensing for

operating, 93 % for storage/transport

Efficiency: 95 - 97 %Type: Pulse Width Modulation (PWM)Control Method: “Soft Turn-On” IGBT PWM for

dV/dt reductionProtection: Thermal overload, short-

circuiting, ground fault, motor phase is missing, over temperature, high and low voltage and Total Harmonic Distortion (THD) protection built in. High speed, semiconductor fuses external.

Optional Bypass: Full Speed / Variable Speed, 3 Phase Transfer Switch, NEMA 12 enclosure

Input: 4-20 mAdcFeedback: 4-20 mAdcAuxiliary Contacts: No Fault and Running

VARIABLE SPEED DRIVE (VSD)Used with UtilitySaver and BurnerMate Combustion Control System

Variable Speed Drives

Suggested Specification1. Variable Speed Drive (VSD)Provide a Pulse Width Modulation (PWM) type VSD suitable for microprocessor-based digital control. The VSD shallaccomplish stepless speed control by adjusting both theoutput voltage and frequency to the motor. The VSD shallutilize IGBT power semiconductor technology in the invertersection. VSDs must be UL listed. Provide a NEMA 12enclosure for the VSD to protect it from dust and splashedwater. VSD shall be sized for 104° F continuous ambient airtemperature conditions. The enclosure shall be completelyself-ventilating with powered fans as required. A NEMAtype 1 rated enclosure will not be accepted. The VSD shallautomatically limit the rate of fan speed increase to thatwhich will prevent an over-current or over-voltage trip inthe event of a “STEP” speed increase of 0 to 100 %. TheVSD shall include a line reactor or DC Link Choke to reducerectifier peak currents, and reduce total harmonic distortion(THD). In order to extend motor insulation life, the VSDshall limit peak voltages. The “dv/dt” shall be limited to 900V/microseconds on a 500 foot cable length between the VSDand motor. VSD’s that do not include internal dv/dt limitingshall be provided with external filters.2. Variable Speed Drive (VSD) BypassThe control system shall include Operator selectable variable speed fan and full speed fan (VSD bypass) air flow controlmodes. Under “Variable Speed” control, both the forced draft fan speed and the air flow control damper shall be used toregulate combustion air flow. Under “Full Speed” control,only the air flow control damper shall be used to regulatecombustion air flow. The controller shall contain independentvariable and full speed fan setup curves for each fuel. In theevent of a Variable Speed Drive (VSD) failure, the burner shall trip, the operator shall be able to transfer the VSD bypasstransfer switch and restart the equipment. The power transfer switch shall be interlocked with the controller for automaticselection of the setup curves. This function shall not requirea service engineer to implement the change-over.

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Controllers and Actuators

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VSD KitThe VSD Kit includes a microprocessor-based VSD drive with a NEMA 12 enclosure and three (3) high speed semiconductor fuses and fuse holders. Fuses are included to replace the existing motor fuses and should be mounted in existing Motor Starter Panel.

Standard Equipment- VSD with NEMA 12 Enclosure- VSD semi-conductor fuses and fuse holder(s)

(shipped loose for mounting in existing motor starterenclosure or VSD Bypass kit fuse enclosure)

Mounting KitThe VSD mounting kit includes unistrut, brackets, and mounting plate sized for one VSD. Parts are shipped loose for field assembly. The UtilitySaver Mounting Kit is sized for mounting the UtilitySaver Panel and VSD Bypass Transfer Switch.

VARIABLE SPEED DRIVE (VSD)Used with UtilitySaver and BurnerMate Combustion Control Systems

VSD Bypass KitThe VSD Bypass Kit allows the boiler operator to change from variable speed to constant speed control by a simple control switch selection. Both full speed and variable speed operation are pre-set in the PCC-III controller configuration. The following equipment is included:

Standard Equipment- Three (3) phase transfer switch with NEMA 12

enclosure- High speed semi-conductor fuse with NEMA 12

enclosure- Three (3) phase distribution terminal block (shipped

loose for mounting in the existing motor starter enclosure)

Variable Speed DriveSimplified Wiring Diagram Variable Speed Drive with Bypass

Simplified Wiring Diagram

12 3

G

FD FanMotor

Variable Speed Drive

New High Speed Semi-Conductor Fuses

GL1 L2 L3

U

L3

L2

L1

V

W

A

COILAUX.

CONTACT

OL

OL

OL

A A A B B B

New High SpeedSemi-Conductor with New Fuse Enclosure

U

L3

L2

L1

V

W

12 3

G

FD FanMotor

Three PhaseTransfer Switch

with New Enclosure

ExistingMotor

Starter

NewExistingMotorFuses

DistributionTerminal Block

L1 L2 L3 G

Variable Speed Drive

203.743.6741 • 203.798.7313www.preferred-mfg.com

Controllers and Actuators

Catalog 25

Controllers &

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299

VARIABLE SPEED DRIVE (VSD)Used with UtilitySaver and BurnerMate Combustion Control Systems

VSD SelectionWhen ordering please verify that the VSD Hp that you have selected is the correct size for your installation. VSDs derate as ambient temperature rises. For the ambient conditions expected, use the table below to compare Maximum Continuous Amps to the motor Nameplate Full Load Amps (FLA). If the motor FLA are lower, your VSD selection is correct.

VSD KitCatalog Numbers Nominal

Hp

VSD Maximum Continuous Amps @Ambient Temperature Weight

lbsVSD VSD Fuses VSD Fuse Holder(s) @ <95° F @ 104° F @ 113° F @ 122° F

Qty Qty 230 Vac:70500-8-240 3 70501-50 1 70503 7.5 24.2 20.6 17.5 14.4 50

70500-10-240 3 70501-50 1 70503 10 30.8 26.2 22.3 18.3 5070500-15-240 3 70501-60 1 70503 15 46.0 39.1 33.2 27.4 6070500-20-240 3 70501-80 3 70504 20 59.4 50.5 42.9 35.4 8070500-25-240 3 70501-125 3 70505 25 74.8 63.6 54.1 44.5 12570500-30-240 3 70501-125 3 70505 30 88.0 74.8 63.6 52.4 12570500-40-240 3 70501-150 3 70505 40 104 88.4 75.1 61.9 15070500-50-240 3 70501-200 3 70505 50 130 110 93.5 77.0 20070500-60-240 3 70501-250 3 70506 50 154 130 110.5 91.0 250

460 Vac:70500-8-460 3 70501-25 1 70502 7.5 11.0 9.4 8.0 6.6 25

70500-10-460 3 70501-30 1 70502 10 14.0 11.9 10.1 8.3 3070500-15-460 3 70501-40 1 70503 15 21.0 17.9 15.2 12.5 40 70500-20-460 3 70501-40 1 70503 20 27.0 23.0 19.6 16.1 40 70500-25-460 3 70501-50 1 70503 25 34.0 28.9 24.6 20.2 5070500-30-460 3 70501-60 1 70503 30 40.0 34.0 28.9 23.8 6070500-40-460 3 70501-80 3 70504 40 52.0 44.2 37.6 30.9 8070500-50-460 3 70501-100 3 70504 50 65.0 55.3 47.0 38.7 10070500-60-460 3 70501-125 3 70505 60 77.0 65.5 55.7 45.9 12570500-74-460 3 70501-150 3 70505 75 117 90.1 76.6 63.1 150

70500-100-460 3 70501-200 3 70505 100 130 110 93.5 77.0 20070500-125-460 3 70501-250 3 70506 125 160 136 115.6 95.2 250

If the motor FLA are larger than the VSD Maximum Continuous Amps, select the next larger VSD size. On retrofit applications, actual motor amps can be measured. Fan motor amps at high fire are typically lower than motor FLA. Measure the FD fan motor amps with the flame ON and at high fire to determine if a larger VSD size is actually required (do not measure during purge).

VSD Bypass Kit:Specify the VSD Bypass Kit based on the Nominal VSD Kit selected above.

VSD Bypass KitCatalog Numbers

Nominal HpVSD

Floor Stand KitCatalog Number

UtilitySaver Panel + Transfer Switch Floor Stand Kit

Catalog NumberTransfer Switch

(Nema 12)

Fuse Enclosure(Nema 12)

Power Distribution

Block230 Vac:

70510 70508 70520 7.5 70516 7051970510 70508 70520 10 70516 7051970510 70508 70520 15 70517 7051970510 70508 70521 20 70517 7051970511 70508 70521 25 70517 7051970512 70509 70521 30 70517 7051970513 70509 70521 40 70518 7051970513 70509 70522 50 70518 7051970513 70509 70522 60 70518 70519

230 Vac:70510 70508 70520 7.5 70515 7051970510 70508 70520 10 70515 7051970510 70508 70520 15 70516 7051970510 70508 70520 20 70516 7051970510 70508 70520 25 70516 7051970510 70508 70520 30 70516 7051970510 70508 70521 40 70517 7051970511 70508 70521 50 70517 7051970512 70509 70521 60 70517 7051970513 70509 70521 75 70517 7051970513 70509 70522 100 70518 7051970513 70509 70522 125 70518 70519

203.743.6741 • 203.798.7313www.preferred-mfg.com

Controllers and Actuators

Catalog 25

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VARIABLE SPEED DRIVE (VSD)Used with UtilitySaver and BurnerMate Combustion Control Systems

Additional Ordering Information1. The Bypass Kit includes Transfer Switch with enclosure,

VSD Fuse Enclosure (Fuses and Fuse Holder(s) notincluded) and Terminal Block. However, these parts must be listed separately when ordering. Specify the TransferSwitch, VSD Fuse Enclosure and 3 Ph Terminal BlockCatalog Numbers

2. Specify VSD and UtilitySaver Mounting Kit CatalogNumbers as required

VSD Component Dimensions and Weights:Nominal Hp VSD Enclosure Transfer Switch Enclosure VSD Fuse Enclosure

H" W" D" Weightlbs H" W" D" Weight

lbs H" W" D"230 Vac:

7.5 32 14 11 77 10 8 6 4 16 14 810 32 14 11 77 10 8 6 4 16 14 815 37 16 11 84 10 8 6 6 16 14 820 37 16 11 108 10 8 6 6 16 14 825 37 16 11 110 10 8 6 9 16 14 830 37 16 11 121 14 12 8 20 20 16 940 37 20 17 229 24 20 8 60 20 16 950 37 20 17 229 24 20 8 60 20 16 960 37 20 17 229 24 20 8 60 20 16 9

230 Vac:7.5 21 11 8 31 10 8 6 4 16 14 810 21 11 8 31 10 8 6 4 16 14 815 32 14 11 106 10 8 6 4 16 14 820 32 14 11 106 10 8 6 4 16 14 825 32 14 11 106 10 8 6 6 16 14 830 32 14 11 112 10 8 6 6 20 16 940 37 16 11 134 10 8 6 6 20 16 950 37 16 11 147 10 8 6 9 20 16 960 37 16 11 154 14 12 8 20 20 16 975 37 20 17 273 24 20 8 60 20 16 9100 37 20 17 273 24 20 8 60 20 16 9125 37 20 17 273 24 20 8 60 20 16 9

Ordering InformationThe VSD Kit includes VSD, Fuses and fuse holder(s). However, these parts must be listed separately when ordering:1. Specify the VSD Catalog Number that provides the

required Voltage, Hp and Maximum Continuous Amps2. Specify the fuses and fuse holder(s) quantity and catalog

numbers (note: below 65 amps (1) three pole fuse holderis required above 65 amps (3) single pole fuse holdersare required)

Consult Factory for different voltages, Hp and amp rating requirements.Consult Factory when applying the VSD Bypass kit to the BurnerMate Control Systems.