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ABB Template

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Rail Car Dumpers. Centrifuges (batch process) Higher HP's and duty cycles. Outline ... Drive specific (HP, Volts, Torque Rating, Duty Cycle) ... – PowerPoint PPT presentation

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Title: ABB Template


1
Presented by Joe Eschleman VP Sales
Marketing Powerohm Resistors Inc.
2
Outline
1. Principles of Dynamic Braking.
2. Regeneration and VF Drives.
3. Methods of braking.
4. Selecting / Sizing Braking Resistors
5. Selecting / Sizing Braking Modules
5. Tools (Powerohm VBR)
3
Outline
1. Principles of Dynamic Braking.
4
Principles of Dynamic Braking.
  • To examine Dynamic Braking we first need to
    understand regeneration.
  • Regeneration is the transfer of energy from the
    motors load back through the motor to the
    Variable Frequency Drive (VFD)
  • Regeneration occurs when the rotor speed exceeds
    synchronous speed of the motor at the applied
    frequency
  • This occurs during speed changes and with
    overhauling load applications. When speed and
    torque act in opposite directions.
  • If regen is not properly dealt with, it can cause
    nuisance Bus Overvoltage trips in Variable
    Frequency Drives
  • Regen is one of the most commonly overlooked
    application issue with Variable Frequency Drives.

5
Sources of Regen Energy
  • Kinetic Energy
  • Rotational motion (based on inertia and velocity)
  • Centrifuge
  • Linear motion (based on mass and velocity)
  • Conveyors
  • Potential Energy
  • Stationary energy (based on height and gravity)
  • Hoist
  • Overhauling Loads
  • Continuous power driven from external sources
  • Winding machines

6
How to deal with Regen.
  • Remember that regen occurs when speed control is
    required.
  • You can use a mechanical brake.
  • Disadvantage is a mechanical brake is a wearable
    part.
  • Electrical Brake (DC Injection Brake, Flux
    Braking)
  • Disadvantage is that the heat is dumped into the
    motor shortening the life expectance of the
    motor.
  • Add a dynamic braking resistor
  • Dynamic braking resistors dissipate the excess
    energy as heat.
  • Use a line regen drive.
  • Regen drives transfer the excess energy back on
    to the incoming AC line.

7
When does Regen occur?Quadrants of Drive
Operation
Torque ()
Speed ()
Speed (-)
Torque (-)
8
When does Regen occur?Quadrants of Drive
Operation
Torque ()
Speed ()
Speed (-)
Torque (-)
9
Quadrant Summary
  • Regeneration occurs when speed and torque act in
    opposite directions.
  • Rotor speed exceeds synchronous speed of applied
    frequency
  • Negative slip
  • Load drives the motor and it becomes a generator
  • Power (Torque x Speed)/5250
  • When torque and speed oppose, power is negative
  • Energy Power x time
  • When power is negative, energy is negative

Negative energy Regenerative energy
10
Outline
2. Regeneration and VF Drives.
11
Regeneration and VF Drives
  • Typical Diagram of an AC Drive?
  • AC line power is converted to DC in the diode
    bridge section of the electronics.
  • The DC bus section then smoothes and filters the
    waveform.
  • The inverter section inverts the DC voltage back
    to AC..
  • The IGBTs of the inverter section are turned on
    and off varying the AC voltage and frequency
    output, thus controlling the speed of the motor.

DC Bus
Diode Bridge
Inverter
12
Regeneration and VF Drives
  • What happens to an AC Drive during regeneration?
  • Motor acts as generator (rotor turns faster than
    synchronous speed of applied Hz)
  • AC from the motor is rectified by the IGBTs
    diodes.
  • Input diode or SCR bridge cannot conduct back to
    the line supply.
  • Energy charges the DC bus capacitors, causing the
    DC bus voltage to rise.
  • The drive trips on Bus Overvoltage

13
Outline
3. Methods of braking.
14
Braking Methods
  • Factors affecting the choice of braking method.
  • Amount of braking (force) needed
  • Amount of control needed
  • Consistent, responsive stop time
  • Consistent stop position
  • Continuous vs. intermittent operation duty
    cycle
  • Braking vs. overhauling
  • Relative cost To Purchase and To Maintain
  • E-Stop categories
  • If heatwhere is it dissipated?

15
Braking Methods - Mechanical
  • Mechanical Braking
  • Advantages
  • Simple, no electronics
  • Failsafe, provides braking when power is removed
    or drive trips.
  • Disadvantages
  • Costly, high maintenance
  • Energy lost as heat
  • Deceleration is not controlled (time, position)

16
Braking Methods - Electrical
  • DC Injection Braking
  • DC current is injected into the motor, forcing it
    to zero speed
  • Advantages
  • Built into most drives, no additional hardware or
    cost
  • Disadvantages
  • Stop is not controlled
  • Energy dissipated as heat in the motor

17
Braking Methods - Electrical
  • Flux Braking
  • Motor flux current is increased
  • Advantages
  • Built into most drives, no additional hardware or
    cost
  • The braking is controlled.
  • Disadvantages
  • Stop is not controlled (non-linear)
  • Most effective at half speed and below
  • Energy dissipated as heat in the motor
  • Not regenerative
  • Useful for deceleration only
  • Not for overhauling

18
Braking Methods - Electrical
  • Bus Regulation
  • As drive decelerates and bus voltage rises, the
    drive automatically extends the ramp to prevent
    excessive bus voltage and drive trip.
  • Advantages
  • No additional hardware required.
  • Disadvantages
  • Not a true braking technique it merely
    mitigates overvoltage trips.

19
Braking Methods - Electrical
  • Braking Chopper and Braking Resistor
  • Chopper control circuitry monitors the DC bus
    voltage
  • If regeneration causes the bus voltage to rise
    above a certain level, the chopper turns on and
    shunts the energy through a DB resistor

? Dynamic Brake or Chopper
20
Braking Methods - Electrical
  • Dynamic Braking
  • Advantages
  • Simple, low cost
  • Controlled braking
  • Removes energy from drive and dissipates heat in
    power resistor specifically designed for the task
  • Suitable for decelerating and overhauling loads
  • Disadvantages
  • Energy is lost to heat
  • Overheating can be a concern
  • Environment

21
Braking Methods - Electrical
Braking vs. Overhauling?
  • Braking
  • Braking is defined as an application in which you
    are decelerating the speed of drive.
  • This could be changing speeds or in the extreme
    case, an E-stop application.
  • Overhauling
  • Overhauling is defined as an application in which
    the motor is being driven by the load on the
    motor, (external forces).
  • A Hoist lowering or tensioning machines.

22
Braking Cycle Curve
Energy Dissipated During Fixed Torque Stop
23
Overhauling Curve
Energy Dissipated During Overhauling
1 pu
t0
24
Braking Methods - Regeneration
  • Line Regeneration
  • Energy is returned to the line supply via an
    external regen module or via an VFD with an
    active converter.
  • Advantages
  • Controlled braking
  • Energy is recycled to the line supply
  • Can provide improved power quality
  • No limitations in duty cycle, suitable for higher
    HPs
  • Disadvantages
  • Relatively costly
  • More complex electronics, more parts
  • Not possible when power source is a generator.

25
Braking Methods - Regeneration
26
Application Examples
  • DC Injection Braking, Flux Braking
  • Applications with intermittent fast stops where
    no precision or consistency is required
  • Conveyors
  • Bus Regulation
  • Applications where tripless operation is required
    but stop time is not critical
  • Conveyors, High Inertia Fans
  • Applications where intermittent overhauling duty
    may occur and speed accuracy is not critical
  • Pump Jacks

27
Application Examples
  • Dynamic Braking
  • Loads requiring quick response for deceleration
    or stopping
  • Conveyors
  • Chipping Heads
  • Centrifuges
  • Intermittent overhauling loads
  • Rotary Kilns
  • Punch Press
  • Pump Jacks
  • Medium HPs and duty cycles

28
Application Examples
  • Line Regeneration
  • Frequent overhauling loads
  • Unwinds
  • Hoists
  • Rail Car Dumpers
  • Centrifuges (batch process)
  • Higher HPs and duty cycles

29
Outline
4. Selecting / Sizing Braking Resistors
30
DB Resistor Sizing
  • Methods of sizing resistor
  • Refer to operation manual or pricing guide.
  • General method (Ohms and Watts) Supplied by
    AB Calculator
  • Drive specific (HP, Volts, Torque Rating, Duty
    Cycle)
  • OEM Specific (HP, Volts, IGBT Rating, Duty Cycle)
  • Application Driven Calculation
  • Powerohm VBR (Variable Braking Resistor
    /Analyzer)

31
DB Resistor Sizing
  • General method (Ohms and Watts)
  • Many customers use their own calculations or
    calculations established by specific drive OEMs
    to come up with an ohms and watts. In this case
    Powerohm designs a resistor using standard
    components to meet the requirement assuming the
    watts is a continuous rating.

32
DB Resistor Sizing
  • Drive specific (HP, Volts, Torque Rating, Duty
    cycle)
  • When given the above information Powerohm uses an
    equation to calculate the continuous watts and
    ohms of the resistor necessary for the given
    requirements.
  • Watts HP 746 Torque Duty Cycle Duty
    Cycle sizing factor
  • Ohms (dcV ) 2 .
  • HP 746 Torque
  • Resistance calculated above must be sized to
    meet the minimum resistance value supplied by
    drive OEM.

33
DB Resistor Sizing
  • OEM Specific (HP, Volts, IGBT Rating, Duty Cycle)
  • Working directly with the drive OEM, resistors
    are sized on the limitations of the brake module
    or 7th IGBT
  • Based on the limitations of the IGBT a maximum
    available braking torque can be calculated.
  • Watts HP 746 Torque Duty Cycle Duty
    Cycle sizing factor
  • Torque rating is minimum of torque required for
    the application vs max torque rating of IGBT
  • Minimum Ohms (dcV) ___ .
  • IGBT current limit

34
DB Resistor Sizing
  • 7th IGBT vs External brake chopper
  • The 7th IGBT may be a limiting factor for the
    braking torque available to a drive. In this
    case a separate brake chopper can be purchased to
    be connected to the drive instead of using the
    7th IGBT.
  • Watts HP 746 Torque Duty Cycle Duty
    Cycle sizing factor
  • Torque rating is minimum of torque required for
    the application vs max torque rating of the motor
  • Minimum Ohms (dcV) .
  • Brake chopper current limit
  • Resistance calculated above must be approved to
    meet minimum resistance value supplied by drive
    OEM.

35
DB Resistor Sizing
  • Duty cycle calculations
  • The duty cycle is determined based on the on time
    versus total of a braking cycle, with the total
    braking cycle not to exceed 2 minutes.
  • Depending upon the duty cycle different watts
    multipliers are used to determine the correct
    continuous rating of the resistor. Higher duty
    cycles require lower multipliers, this is to
    account for the high peak currents of the lower
    duty cycles.

36
AB Calculator (Jeff Theisen)
37
AB Calculator (Jeff Theisen)
38
AB Calculator (Jeff Theisen)Any Resistor
Selected from Drop Down Menu
39
AB Calculator (Jeff Theisen)Power Resistor
Selected from Drop Down Menu
40
AB Calculator (Jeff Theisen)Finite Resistor
Pick List
41
1336 Brake Chopper and Resistor Table
42
1336 Brake Chopper and Resistor Table
43
Raise SoftwareProduct Configurator
44
Raise SoftwareProposal Works
45
Outline
5. Selecting / Sizing Braking Modules
46
Overview
  • Ratings, Technical Data, Monitored Conditions and
    Protection
  • Frame Sizes, Weights and Dimensions
  • Part Numbers
  • Operation and Maintenance Manual
  • Brochure and Release Dates

47
Ratings
  • Continuous Amps
  • 50, 115, 300, 600, 900 and 1200 amp
  • (Units above 50 amp include fan)
  • Voltage Ratings
  • 240, 480, 600 volts (690 for 300 amps and
    above)
  • Ambient Temperature
  • -10 to 40 Deg C
  • Logic Power Supply
  • Derived from DC Bus _at_ 40 Watts Nominal
  • Derived from 115 VAC for 300 amps and above
  • Fan Supply
  • Single Phase 115 VAC

48
Input / Output Low Capacity 50 and 115 amp units
  • Enable
  • Internal/External Jumper Programmable
  • Enable is 115 VAC, also provides fan power if
    equipped.
  • Master Output
  • Slave Input
  • Fault Contacts
  • Jumper Programmable NO or NC (factory default is
    NC)

49
Monitored Conditions Low Capacity 50 and 115
amp units
  • Shorted IGBT Transistor
  • Open or Absent Resistor Load Bank
  • Logic Supply Undervoltage
  • Heatsink Over Temperature Shutdown

50
Input High Capacity 300 through 1200 amp units
  • Power
  • Derived from single phase AC voltage.
  • I/O
  • All high capacity modules have additional
    standard I/O features compared to lower capacity
    modules. Higher current ratings generally are or
    may be associated with more complex drive
    systems.
  • Enable
  • Close Contact to enable

51
Input Continued High Capacity 300 through
1200 amp units
  • Master / Slave Signal
  • Pulse train, Bi-directional signal, two terminal
  • IOC, (Instantaneous Over Current)
  • Reset Momentary contact closure
  • IOV, IUV (Instantaneous Over/Under Voltage)
  • Reset Momentary contact closure
  • Master/Slave Select
  • Default Slave, Contact Closure Master
    Selected
  • DC Bus Discharge
  • Close Contact to discharge

52
Output High Capacity 300 through 1200 amp units
  • Logic Section Ready Normally Closed
  • Power Section Ready Normally Closed
  • Master / Slave Status Closed when Master
  • IOC, IOV Normally Closed
  • IOV, IUV Normally Closed
  • Over temperature Normally Closed
  • Logic Voltage Valid Normally Closed
  • IGBT Shorted Normally Closed

53
Protection High Capacity 300 through 1200 amp
units
  • Logic Supply Undervoltage Shutdown / Lockout
  • IOC Shutdown
  • IOC, IOV Shutdown
  • Heatsink Over Temperature Shutdown

54
Options High Capacity 300 through 1200 amp units
  • Profibus I/O Module.
  • Standard hardware I/O remains active.
  • Fiber optic link for Master pulse transmission
    between modules.
    Recommended in
    high noise environments when multiple modules are
    used.

55
Powerohm Type BM Low Capacity Braking Module
56
Powerohm Type BM High Capacity Braking Module
57
IMPORTANT These instructions should be read
thoroughly before installation. All warnings and
precautions should be observed for both personal
safety and for proper equipment performance and
longevity. Failure to follow these instructions
could result in equipment failure and/or serious
injury to personnel.
58
Outline
5. Tools (Powerohm VBR)
59
Powerohm VBR
  • Powerohm Variable Braking Resistor
  • The Powerohm VBR is a portable test unit that
    provides selectable steps of resistance for
    analyzing your braking requirements for a wide
    range of drive horse powers. Simply connect the
    VBR to your drive or braking module and let the
    application decide what braking resistor it needs.

60
Powerohm VBR
  • Powerohm Variable Braking Resistor
  • This easy to use diagnostic tool provides the
    user with eleven (11) selectable settings of
    resistance.

61
Powerohm VBR
  • Powerohm Variable Braking Resistor
  • After selecting the resistance value suitable for
    your drive, connect the plus (red) and minus
    (black) leads to the output of the Brake Chopper
    section (imbedded within the Drive or stand alone
    external). Now run your application for a
    minimum of 30 minutes.

62
Powerohm VBR
  • Powerohm Variable Braking Resistor
  • After running your application for 30 minutes you
    will notice the digital readout has changed to
    higher value.
  • Pressing the up arrow key will provide you with
    the peak readout during your cycle.
  • Together with this peak number and the resistance
    value you selected you are now ready to determine
    the ideal resistor for your application.

63
Powerohm VBR
  • Powerohm Variable Braking Resistor

64
Powerohm Resistors, Inc.Engineered Diversity for
the Braking Resistor Industry
65
Summary
  • Questions?
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