Download - ACDC drives
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The DC Drive
In the beginning
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6 Basic Adjustments
Speed Reference Minimum Speed Maximum Speed Acceleration Deceleration Current Limit
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Typical DC Drive
Adjustments
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Adjustments - Speed Reference
Speed Reference Typically it is a potentiometer that an operator
turns to adjust the speed of the machine.
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AdjustmentsMin. Speed
Minimum Speed How fast the machine will operate with the Speed
Reference turned all the way DOWN.
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AdjustmentsMax. Speed
Maximum Speed How fast the machine will operate with the Speed
Reference turned all the way UP.
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Adjustments - Acceleration
Acceleration Rate How much time it will take to go from stop to full
speed.
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Adjustments - Deceleration
Deceleration Rate How much time it will take to go from full speed to
stop.
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Adjustments - Current Limit
Current Limit This limits the amount of current coming out of the
drive. Its based on the motors Full Load Amps.
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Basic DC Drive Operations
Speed Reference - How fast you want themachine to go.
Can be analog 0 - 10vdc or 4 - 20mA signalfrom a controller.
Can also be a adjustment via parameter,network data or keypad input
Signal is modified by Min. and Max. SpeedAdjustments Goes to the Ramp Circuits
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Basic DC Drives Operations
Ramp (Rate) circuits get the speed referenceand ramps the signal up over a period of
time.
The time periods are adjustable via a pot,parameter or network data.
Output goes to a summing junction.
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Basic DC Drive Operations
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Basic DC Drive Operations
Summing Junction Takes the signal from the Ramp circuits and adds
them together with some sort of feedback.
Feedbacks can be speed,voltage or current. The result out of the summing junction is an error
signal indicating the difference between the speed
reference and the feedback. Another way to look
at it is difference between how fast I want it to goverses how fast it is actually going
Output goes to the Major Loop (Speed or Voltage
Loop)
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Basic DC Drive Operations
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Basic DC Drive Operations
Major Loop Operational Amplifier (Loop 2) The speed error signal from the summing junction
is the input. This amplifies the error signal.
There is a feedback loop around the amplifier.This loop has a resister and capacitor (digital
drives would be integrator and proportional
response)
Tuning these values of the feedback loop willaffect the overall response (stability) of the drive.
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Basic DC Drive Operations
Stability
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Basic DC Drive Operations
Second Summing Junction The input to this junction is the amplified error
signal out of the Major Loop (Loop 2) operational
amplifier. The signal is now called CurrentReference.
Current Reference is Summed together with the
current feedback signal.
The output signal goes to the Current Minor Loop(Loop 1) Operational Amplifier.
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Basic DC Drive Operations
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Basic DC Drive Operations
Current Minor Loop (Loop 1) The current error signal from the summing
junction is the input. This amplifies the error
signal.
There is a feedback loop around the amplifierwhich is a resistor and capacitor. (Digital
drives is Integrator & Proportional response) Tuning these values will affect overallresponse (stability) of the drive.
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Basic DC Drive Operations
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Basic DC Drives Operations
Gate Pulse Driver Circuits These circuits provide the pulse to the gate inputs
on all the SCRs. Input from CML.
Everything in the drive up to this point is there totell these circuits when to fire.
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Gate Pulse Timing
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Basic DC Drive Operations
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Basic DC Drive Operations
Power Module This is where the SCRs live.
The Power Module has AC power connected to it
which is what gets switched (through the SCRs)to the motor armature circuit as DC.
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Basic DC Drive Operations
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SCR Construction
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Typical DC Drive - SCRs
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Power Module (SCRs)
Non-Regen
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Power Module (SCRs)
Regen
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Basic DC Drive Operations
Motor The interaction of 2 magnetic fields causes
rotation (armature & field).
Typically the Field coils have a constant voltageapplied and we vary the voltage in the armature to
get variable speed (up to Base speed)
To go above base speed we have constant
maximum voltage in the armature and then weweaken the field voltage.
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Speed Regulator
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Voltage Regulator
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Current Regulator
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Position Regulator
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Force Transducer
Tension Regulator Basic
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Contactor Reversing
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3 Basic Types of Braking
Coast to Rest Dynamic Braking Regenerative Braking
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Braking Methods
Coast to Rest The application coasts to a stop. Time to rest is
determined by Friction, Windage and Inertia of the
load. Dynamic Braking
Inertia contained in a load causes the load to
continue rotating generating a voltage and current
in the armature circuit opposite in direction ofmotoring and being dropped across a high
wattage resistor.
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Braking Methods
Regeneration Inertia contained in a load causes the load to
continue rotating generating a voltage and current
in the armature circuit opposite in direction ofmotoring current. Using a second set of SCRs
connected opposite than the first set, these are
fired so that current flow is allowed to flow in the
opposite direction back to the AC line supply.
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4 Quadrant Operations
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DC Dynamic Braking
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Braking Force
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Stopping Methods Compared
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The AC drive
Then there was AC
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AC Drive Power Section
Motor
AC Line
InverterInputrectifier
Filter
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PWM waveform is a series of repetitive Voltage pulses
1
3
+ DC Bus
- DC Bus
VLL @ Drive500 Volts / Div.
Phase Current10 Amps / Div.
M2.00 s Ch1 1.18V
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NEMA Enclosures For Drives
NEMA TYPE 1 - General Purpose Indoor, Nonvent &
Ventilated
Designed for use indoorsIntended for areas where no unusual service conditions exist (relatively
clean/dry)
Prevent accidental contact with the enclosed equipment
Panels are louvered and not sealed/gasketed
Provide good protection against falling dirt
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NEMA Enclosures For Drives
NEMA TYPE 1 - General Purpose Indoor, Nonvent &
Ventilated
5 HP SP500 w/Mains FilterFlexPak 3000 w/NEMA 1 Enclosure
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NEMA Enclosures For Drives
NEMA TYPE 4 - Water-tight/Dust-tight, Indoor/Outdoor
NonventilatedIntended for use indoors to protect against:
Splashing water
Falling or hose-directed water
Seepage of water
Severe external condensationMust have conduit hubs for water-tight connection at conduit entrance
Mounting method must be external to equipment cavityNo louvers, no ventilated openings
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NEMA Enclosures For Drives
NEMA TYPE 4 - Water-tight/Dust-tight, Indoor/Outdoor
Nonventilated
Gaskets on doors
NEMA Type 4X are also corrosion-resistant
NEMA 4/12 1 HP MinPak PlusSP500
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NEMA Enclosures For Drives
NEMA TYPE 12 - Dust-tight/Drip-tight, Indoor
Nonventilated
Suitable for indoor industrial applicationsDesigned to protect against:
Fibers wFlyings wLint
Dust wDirt wLight splashings
Seepage wDrippings
External condensation of noncorrosive liquids
All holes/conduit openings must have oil-tight gaskets and use oil-tight or dust-tight mounting mechanisms
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NEMA Enclosures For Drives
NEMA TYPE 12 - Dust-tight/Drip-tight, Indoor
Nonventilated
Doors must have oil-resistant gasketsMounting method must be external to equipment cavity
Enclosures must have captive closing hardware and provision for locking
Reliance often times combines Type 4 with Type 12 to make a versatile NEMA
4/12 (water/dust) enclosure
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NEMA Enclosures For Drives
NEMA TYPE 12 - Dust-tight/Drip-tight, Indoor
Nonventilated
Type 4/4X/12 Type 12Type 4X/12
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Open Loop AC
Cl d L AC
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Closed Loop AC
Vector
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Open Loop SensorLess
3 C t f V t
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TorqueCurrent
MagnetizingCurrent
Motor
Current
3 Components of Vector
Control
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TorqueCurrent
Magnetizing Current
Motor
Current
90 Degrees
Torque is optimized by maintaining Magnetizing & Torque Current @ 90 degrees
Optimizing Torque output
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Identified during Auto-tuning
Typically ranges from 30%- 50% of Motor FLA
Fixed from 0% to 95% of Motor Base RPM
Proportionally decreased in Field Weakening Range
95% MotorBase RPM
Motor Base RPM
Fixed @ 30% - 50% FLA
Magnetizing Current is decreasedin the Field Weakened area
Magnetizing Current
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Represents the actual load at the motor shaft
Current demand above Magnetizing is Torque
95% Motor Base RPMMotor Base RPM
Torque Current varies from Magnetizing to Max FLA
Magnetizing Current is fixed Mag. Current is decreased
Torque Current
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The vector sum of Magnetizing and Torque Current
Regulated by internal current feedback
95% Motor Base RPM Motor Base RPM
Torque Current varies from Magnetizing to Max FLAMotor Currentis the sum ofMagnetizing
and Torque
Magnetizing Current is fixed Mag. Current decreases
Motor Current
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General Purpose Mode V/Hz
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Vector Mode Torque Curve
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Constant Torque Load
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Variable Torque Loads
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AC Snubber Braking
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AC Regeneration
Transportation Application
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Transportation Application
Matrix
Metals Application
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Metals Application
Matrix
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Paper Application
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Paper Application
Matrix
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Consumer Application
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Consumer Application
Matrix
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Gas/Oil/Mining Application
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Gas/Oil/Mining Application
Matrix
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THE END
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Notes
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Notes
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Notes
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Notes
N t
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Notes