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Allen-Bradley 20P21AE270RA0NNN PowerFlex DC Drive

1. Product Overview

The Allen-Bradley 20P21AE270RA0NNN is a high-power PowerFlex DC Drive designed for industrial DC motor control applications requiring substantial armature current capacity, stable speed regulation, controlled acceleration and deceleration, and reliable operation in demanding production environments.

This model is rated at 270 A DC and 200 HP, making it suitable for large industrial DC motors used in material handling, conveyors, winding equipment, paper processing, printing machinery, machine tools, process equipment, and other heavy-duty applications.

The 20P21AE270RA0NNN belongs to the PowerFlex DC series and uses a three-phase AC input with a six-pulse input configuration. It is a non-regenerative, two-quadrant DC drive, intended for applications where the motor primarily operates in the forward motoring and forward braking regions rather than requiring four-quadrant regenerative operation.

The drive is designed for an industrial installation environment and uses an IP20 / NEMA/UL Type Open enclosure arrangement. The particular catalog configuration includes conformal coating, a blank front plate instead of a Human Interface Module, and no standard communication module.

For a 200 HP DC motor, the 20P21AE270RA0NNN provides a considerably higher current capability than the smaller 50 HP, 75 HP, or 100 HP models in the same family. This makes it especially useful where the motor has high starting torque requirements, substantial mechanical inertia, or continuous-duty industrial loading.

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2. Brand Information

Parameter	Description
Brand	Allen-Bradley
Product Family	PowerFlex
Product Series	PowerFlex DC
Product Type	Digital DC Drive
Model	20P21AE270RA0NNN
Drive Rating	200 HP
DC Output Current	270 A
Input Voltage Class	500–600 VAC class
Typical Input Voltage	575 VAC
Input Phase	Three-phase
Input Type	6-pulse
Motor Operation	Two-quadrant
Regeneration	Non-regenerative
Enclosure Type	IP20 / NEMA/UL Type Open
Field Supply	Single-phase regulated
Human Interface Module	No HIM / blank plate
Communication Module	None
Conformal Coating	Yes
Frame Size	Frame B

The model is part of the PowerFlex DC family, a family intended specifically for industrial DC motor control rather than conventional low-voltage AC motor speed control.

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3. Main Technical Parameters

The following table summarizes the most important parameters of the 20P21AE270RA0NNN.

Parameter	Specification
Model	20P21AE270RA0NNN
Product Series	PowerFlex DC
Brand	Allen-Bradley
Drive Type	Digital DC Drive
Rated Motor Power	200 HP
Rated Motor Power	Approximately 149 kW
Rated DC Current	270 A
AC Input	Three-phase
AC Input Voltage Class	500–600 VAC
Typical Nominal Input	575 VAC
Input Frequency	50/60 Hz industrial supply class
Input Configuration	6-pulse
Motor Type	Industrial DC motor
Motor Operation	Two-quadrant
Regenerative Operation	No
Field Supply	Single-phase regulated
Enclosure	IP20
Enclosure Style	NEMA/UL Type Open
Frame	Frame B
Communication Option	None-Standard
HIM	No HIM / Blank Plate
Coating	Conformal coated electronics
Installation	Panel / cabinet mounting
Application Type	Heavy-duty industrial DC motor control
Approx. Height	311 mm
Approx. Width	388 mm
Approx. Depth	350 mm
Approx. Drive Weight	29.5 kg
Approx. Packaged Weight	31.5 kg

The dimensions and weight above correspond to the applicable Frame B configuration and should be treated as mechanical planning information. Actual cabinet fabrication should always be checked against the specific mechanical drawing and installation requirements of the supplied unit.

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4. Electrical Rating

The most important feature of the 20P21AE270RA0NNN is its 270 A DC output capability.

A 270 A rating places this drive in the high-power section of the PowerFlex DC range. In the 575 VAC three-phase non-regenerative configuration, this corresponds to a 200 HP / approximately 149 kW motor rating.

This rating is particularly important for applications where the motor must deliver considerable torque for extended periods.

For DC motors, armature current has a direct relationship with motor torque. As a result, a drive with a 270 A current rating can provide the current required by large DC motors without forcing the drive to operate continuously at or beyond its rated capacity.

The associated AC line current for this rating is approximately 220.6 A, and a commonly associated input line reactor configuration is 1321-3RB250-B for this drive class.

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5. 200 HP Motor Capacity

The 20P21AE270RA0NNN is designed around a 200 HP normal-duty rating.

A 200 HP DC motor is commonly found in industrial machinery where relatively high mechanical power is required continuously or repeatedly.

Typical examples include:

• Large conveyors
• Steel processing machinery
• Paper machines
• Printing machinery
• Large winding systems
• Material handling equipment
• Hoists and lifting equipment
• Large machine tools
• Textile processing systems
• Process lines
• Industrial fans
• Pumps
• Roll drives
• Web handling systems

The 200 HP rating should not be interpreted simply as a universal motor-size recommendation. Actual drive selection depends on motor nameplate current, field voltage, armature voltage, duty cycle, ambient temperature, overload requirements, speed range, feedback requirements, and application-specific operating conditions.

For retrofit projects, the motor nameplate current is particularly important. A motor rated at approximately 200 HP does not automatically mean that every 200 HP DC motor has exactly the same electrical requirements.

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6. Three-Phase AC Input

The 20P21AE270RA0NNN uses a three-phase AC input.

The drive is intended for the 500–600 VAC class, commonly associated with a 575 VAC industrial power system.

This makes the model appropriate for industrial facilities where medium-voltage-class low-voltage distribution systems are used to supply large production equipment.

The three-phase input is converted by the drive into controlled DC power for the motor armature.

The power conversion structure allows the controller to regulate the DC motor’s armature voltage and current, which in turn controls motor speed and torque.

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7. Six-Pulse Input

The model uses a 6-pulse input configuration.

A six-pulse converter is a well-established industrial power conversion arrangement and has historically been widely used for high-power DC motor drives.

The basic conversion process can be understood as:

Three-phase AC power → controlled power conversion → DC armature power → DC motor

The six-pulse structure is particularly familiar to maintenance engineers working with older DC drive systems.

For retrofit work, this can be an important advantage because technicians who are already familiar with conventional DC drive architecture can usually understand the basic power path without having to learn an entirely different conversion concept.

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8. Two-Quadrant Motor Operation

The 20P21AE270RA0NNN is a two-quadrant drive.

Two-quadrant operation is appropriate for many applications where the motor operates primarily in one direction and requires controlled braking without the full four-quadrant regenerative capability.

In practical terms, the drive can provide controlled motor operation in the intended direction and controlled deceleration.

Applications such as conveyors, pumps, fans, and many continuous-process machines may not require four-quadrant operation.

For applications where the motor must frequently reverse direction under load or where energy must be returned to the electrical supply during braking, a regenerative PowerFlex DC model may be more appropriate.

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9. Non-Regenerative Configuration

The 20P21AE270RA0NNN is a non-regenerative model.

This distinction is important when selecting a DC drive.

A non-regenerative drive is normally used when the application does not require the drive to continuously return braking energy to the incoming AC supply.

Typical applications include machinery where:

• The motor normally rotates in one direction.
• Braking requirements are moderate.
• The load does not continuously drive the motor.
• Regeneration is not required.
• Controlled stopping is sufficient.
• Mechanical braking can handle additional stopping requirements.

If the application involves frequent reversing, lowering heavy loads, or sustained overhauling conditions, the regenerative version of the same rating may be considered.

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10. Field Supply

The 20P21AE270RA0NNN uses a single-phase regulated field supply.

The field circuit is an important part of a separately excited DC motor system.

Unlike a simple AC induction motor, a DC motor’s field and armature circuits can be separately controlled.

This gives the drive greater flexibility when controlling motor speed and operating range.

The regulated field supply can be useful for applications that require:

• Stable motor field control
• Field weakening
• Extended speed range
• Controlled field current
• Improved operating consistency
• Field economy functions

Correct field voltage and field current must always be matched to the motor nameplate and motor manufacturer’s requirements.

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11. IP20 / NEMA/UL Type Open Construction

The drive is specified with an IP20 / NEMA/UL Type Open enclosure arrangement.

This means the drive is generally intended to be installed inside an appropriate electrical enclosure or cabinet rather than being installed directly in an exposed outdoor environment.

Cabinet design should take into account:

• Cooling airflow
• Heat dissipation
• Clearance around the drive
• Cable routing
• Grounding
• Protection against dust
• Protection against moisture
• Access for maintenance
• Separation between power and control wiring

For a 270 A drive, thermal management becomes particularly important because the electrical losses can generate significant heat inside a cabinet.

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12. Conformal Coating

The 20P21AE270RA0NNN configuration includes conformal coating.

Conformal coating provides an additional protective layer over electronic circuitry.

This feature can be valuable in industrial environments where equipment may encounter:

• Dust
• Humidity
• Condensation risk
• Industrial contaminants
• Mild corrosive atmospheric conditions
• Process-related airborne particles

Conformal coating does not make the drive waterproof or suitable for direct exposure to liquids.

The enclosure and installation environment must still provide appropriate environmental protection.

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13. No HIM / Blank Plate

This particular catalog configuration is supplied with No HIM, meaning that it uses a blank plate rather than a standard local Human Interface Module.

This configuration is often suitable for installations where the drive is controlled through external control circuitry, a PLC system, analog signals, or other supervisory equipment.

The absence of a local HIM can also be useful when the drive is installed inside a dedicated control cabinet and local keypad operation is not part of the normal operating procedure.

For maintenance work, however, technicians should make sure that an appropriate commissioning and diagnostic method is available through the control architecture.

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14. No Standard Communication Module

The catalog configuration also specifies No Standard Communication Module.

This means the drive is not configured with an additional standard communications option as part of this catalog number.

This does not necessarily mean that the drive cannot be integrated into an industrial control system.

Depending on the overall system design and available options, control can be implemented through hardwired signals, analog interfaces, feedback devices, or appropriate communication hardware.

For a retrofit, the existing machine’s control architecture should be examined before replacing the original DC drive.

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15. Dimensions and Weight

The physical size of the drive is important when replacing an older DC drive.

For the applicable Frame B configuration, the approximate overall dimensions are:

Mechanical Parameter	Approximate Value
Model	20P21AE270RA0NNN
Frame	Frame B
Height	311 mm
Width	388 mm
Depth	350 mm
Approx. Drive Weight	29.5 kg
Approx. Packaged Weight	31.5 kg
Mounting Style	Panel / cabinet
Enclosure	IP20 / Open Type

The 29.5 kg drive weight is a useful figure for cabinet structural planning and handling calculations.

The approximately 31.5 kg packaged weight includes packaging and therefore should not be used as the installed equipment weight.

The dimensions should be treated as approximate mechanical dimensions. Cabinet builders should allow additional space for cable bending radius, ventilation, terminal access, maintenance access, and safe working clearance.

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16. Product Introduction

The 20P21AE270RA0NNN is a high-current digital DC motor controller designed for industrial equipment that still uses conventional DC motors.

DC motors remain in service in many industrial machines because they can provide strong starting torque, wide speed-control capability, and excellent controllability.

Although AC variable-frequency drives have become extremely common, many existing industrial machines were originally engineered around DC motors.

Replacing the entire motor, gearbox, mechanical transmission, and control system can be considerably more complicated than replacing the drive itself.

This is one reason high-power DC drives such as the 20P21AE270RA0NNN remain relevant for industrial modernization and maintenance projects.

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17. Typical DC Motor Control Architecture

A typical system using the 20P21AE270RA0NNN can be viewed as several functional sections:

Three-phase AC supply

↓

Input protection and switching

↓

Line reactor / power conditioning

↓

PowerFlex DC drive

↓

Controlled DC armature output

↓

DC motor

At the same time, the motor field is supplied and regulated through the field supply section.

Control signals can come from:

• Start/stop circuits
• PLC outputs
• Analog speed references
• External speed potentiometers
• Process controllers
• Feedback devices
• Machine sequencing systems

This architecture allows the drive to become part of a much larger automated production system.

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18. Conveyor Applications

Large conveyors are one of the natural applications for high-power DC drives.

A conveyor carrying heavy material can require considerable torque during acceleration.

The 20P21AE270RA0NNN can be used where the existing conveyor motor is a suitably rated DC motor and the required armature current is within the drive’s rating.

Potential applications include:

• Mining conveyors
• Bulk material conveyors
• Steel plant conveyors
• Paper mill conveyors
• Heavy manufacturing conveyors
• Long process conveyors
• Material transfer systems

Controlled acceleration is particularly useful because abruptly applying full motor voltage can cause mechanical shock.

A properly configured DC drive can increase motor output in a controlled manner, helping reduce stress on belts, couplings, gearboxes, shafts, and other mechanical components.

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19. Winding and Unwinding Equipment

Winding machinery is another important application area.

A winding machine must maintain consistent material tension while the roll diameter changes.

The motor speed and torque must therefore be controlled carefully.

DC motors have historically been widely used in:

• Roll-to-roll processing
• Web handling
• Film processing
• Paper winding
• Cable winding
• Textile winding
• Metal strip processing

The drive can regulate motor speed while the machine control system manages the process reference.

For an existing machine designed around a DC motor, maintaining the original motor while modernizing the drive can be a practical approach.

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20. Paper and Pulp Machinery

The paper industry has historically made extensive use of DC motors.

Large paper-processing machines may contain multiple drive sections that must operate at coordinated speeds.

Examples include:

• Paper machine sections
• Roll drives
• Calender sections
• Rewinders
• Unwinders
• Slitter rewinders
• Coating equipment
• Sheet handling systems

The 20P21AE270RA0NNN can be appropriate for large motor sections where a 270 A DC drive rating is suitable.

The ability to maintain controlled speed is important because paper tension and synchronization can directly influence finished product quality.

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21. Printing Machinery

Large printing systems can require coordinated motor control.

Older industrial printing presses often use DC motors because of their speed-control characteristics.

Applications may include:

• Printing presses
• Web presses
• Rollers
• Feed systems
• Rewind systems
• Material handling sections
• Coating systems

The drive can provide a controlled motor speed reference and help the machine maintain consistent operating conditions.

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22. Textile Machinery

Textile processing equipment often requires smooth speed control.

Potential applications include:

• Spinning machinery
• Winding machines
• Textile rollers
• Drawing machines
• Finishing machinery
• Fiber-processing equipment

A DC drive can be particularly useful in retrofit situations where the mechanical system and DC motor remain in good condition.

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23. Pump Applications

The 20P21AE270RA0NNN can also be used with large DC-motor-driven pumps where the motor and drive ratings are appropriate.

Examples include:

• Industrial process pumps
• Cooling-water systems
• Circulation systems
• Large water handling systems
• Process fluid pumps

For pump applications, speed control can help adjust flow according to the process requirement.

However, the motor’s actual current, speed range, field requirements, and pump characteristics must be checked before selecting the drive.

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24. Fan Applications

Large industrial fans can require significant motor power.

A DC drive can regulate fan speed according to the process requirement.

Potential applications include:

• Industrial ventilation
• Furnace fans
• Process exhaust systems
• Cooling fans
• Air handling systems
• Large industrial blowers

Reducing motor speed when full airflow is not required can also reduce mechanical and electrical loading.

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25. Material Handling

Heavy-duty material-handling equipment is another potential application.

Examples include:

• Hoists
• Rollers
• Transfer systems
• Large material feeders
• Heavy conveyors
• Industrial handling machines

For applications where the load can drive the motor during lowering or deceleration, the regeneration requirements must be examined carefully.

A non-regenerative two-quadrant drive should not automatically be selected for a load that requires continuous regenerative braking.

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26. Machine Tool Applications

Large machine tools may use DC motors for spindle or auxiliary functions.

The 20P21AE270RA0NNN may be suitable where the motor’s electrical characteristics match the drive.

Potential examples include:

• Large lathes
• Heavy-duty mills
• Rolling equipment
• Large grinding machines
• Specialized production machinery

The drive’s speed regulation and current control can be useful where the machine requires stable motor operation.

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27. Main Product Advantages

High 270 A Current Rating

The biggest advantage of the 20P21AE270RA0NNN is its substantial 270 A DC output capability.

This allows the drive to control large industrial DC motors in the approximately 200 HP class.

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200 HP Industrial Capability

A 200 HP rating places the unit in a high-power industrial category.

It can therefore be used for machinery that requires considerably more motor power than smaller PowerFlex DC models.

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Digital DC Control

Digital control provides considerably more flexibility than older analog DC drive systems.

Digital configuration allows parameters to be adjusted for:

• Speed control
• Current control
• Acceleration
• Deceleration
• Field control
• Feedback
• Protection
• Operating limits

This makes the drive useful for modernization of older industrial machinery.

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Two-Quadrant Operation

Two-quadrant operation provides controlled motor operation without the complexity of a full regenerative drive.

For applications that do not require four-quadrant operation, this can provide an appropriate balance between functionality and system complexity.

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Regulated Field Control

The regulated field supply gives the motor control system more flexibility than a basic uncontrolled field arrangement.

This can be useful for field weakening and extended-speed applications where the motor is designed for such operation.

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Conformal-Coated Electronics

The conformal-coated configuration provides an additional level of protection for the electronic circuitry.

This can be beneficial in industrial environments where humidity and airborne contamination are concerns.

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Familiar DC Drive Architecture

The PowerFlex DC architecture is familiar to many industrial maintenance departments.

For plants with existing DC motors, this can reduce the need to redesign the entire mechanical system.

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28. Advantages for Retrofit Projects

One of the strongest practical reasons for selecting a DC drive in an existing machine is that the drive can modernize the control system without necessarily replacing the complete motor system.

A retrofit project may involve:

• Existing DC motor
• Existing gearbox
• Existing mechanical transmission
• Existing encoder
• Existing tachometer
• Existing control cabinet
• Existing machine PLC

Replacing only the drive can potentially reduce mechanical modifications.

The actual feasibility depends on the age and condition of the motor, feedback system, insulation, bearings, brushes, commutator, field circuit, and existing electrical equipment.

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29. Speed Control

Speed regulation is one of the most important functions of a DC drive.

The 20P21AE270RA0NNN can be integrated into a system where motor speed is controlled according to a process reference.

The reference can be generated by:

• PLC logic
• Analog signals
• External controllers
• Machine operator controls
• Process feedback

In applications such as paper, textile, winding, and printing machinery, stable speed control is particularly important.

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30. Acceleration Control

Large 200 HP motors should generally not be accelerated abruptly.

A controlled acceleration profile can help reduce mechanical shock.

Benefits can include reduced stress on:

• Couplings
• Gearboxes
• Shafts
• Bearings
• Conveyor belts
• Chains
• Rollers
• Machine frames

The acceleration profile should be configured according to the actual machine and load.

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31. Deceleration Control

Controlled deceleration is equally important.

Stopping a large rotating load too quickly can create significant mechanical stress.

The drive can therefore be configured to provide controlled deceleration within the limitations of the application and motor.

For loads that contain significant stored kinetic energy, braking and regeneration requirements must be evaluated during system design.

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32. Input Line Reactor Consideration

For the 20P21AE270RA0NNN, the associated line reactor selection commonly identified for the 575 VAC class is:

Parameter	Value
Drive Model	20P21AE270RA0NNN
DC Current	270 A
AC Line Current	Approximately 220.6 A
Motor Rating	200 HP
Approx. Motor Power	149 kW
Associated Line Reactor	1321-3RB250-B
Reactor Rating	Approximately 149 kW / 200 HP class

A line reactor can help reduce certain input-side disturbances and can provide impedance between the supply and the drive.

Actual installation requirements depend on the electrical system, local standards, transformer impedance, fault level, harmonic considerations, and the overall power-distribution design.

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33. Cooling and Cabinet Design

At 270 A, thermal management should be taken seriously.

The drive generates heat during normal operation, and this heat must be removed from the enclosure.

A suitable cabinet design should consider:

• Ambient temperature
• Internal cabinet temperature
• Ventilation
• Fan capacity
• Airflow direction
• Heat dissipation
• Filter condition
• Clearance around the drive
• Nearby heat-producing equipment

Installing a large DC drive inside an undersized enclosure can create excessive internal temperature and shorten component life.

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34. Maintenance Considerations

Although digital drives reduce many maintenance requirements, high-power DC motor systems still require regular inspection.

Maintenance should normally include:

• Checking cabinet cleanliness
• Inspecting cooling fans
• Inspecting terminals
• Checking cable connections
• Checking grounding
• Inspecting motor brushes
• Inspecting commutator condition
• Checking motor bearings
• Checking field wiring
• Checking feedback devices
• Reviewing drive alarms
• Inspecting signs of overheating

The drive should not be treated as an isolated component. The motor and mechanical load are equally important parts of the system.

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35. DC Motor Brush and Commutator Maintenance

Unlike most modern AC induction motors, conventional DC motors commonly use brushes and commutators.

This means the motor itself requires maintenance that is not normally required by a standard squirrel-cage induction motor.

Maintenance personnel should monitor:

• Brush wear
• Brush pressure
• Brush seating
• Commutator surface
• Sparking
• Carbon dust
• Armature condition
• Bearing condition

If excessive sparking occurs, the problem should not automatically be attributed to the drive.

Motor mechanical condition, commutation, brush setting, field strength, feedback, and load conditions should all be investigated.

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36. Feedback and Closed-Loop Applications

Many high-performance DC motor systems use feedback.

Depending on the machine design, feedback may come from:

• DC tachometer
• Encoder
• Other compatible speed feedback devices

Feedback can improve speed regulation because the controller can compare the desired speed with actual motor speed.

This is particularly useful in:

• Winding machines
• Printing machinery
• Paper machinery
• Textile machines
• High-precision production systems
• Coordinated multi-drive systems

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37. Product Selection Considerations

Before replacing an existing DC drive with the 20P21AE270RA0NNN, several motor parameters should be checked.

The following information should ideally be taken directly from the motor nameplate and machine documentation:

Selection Parameter	What to Check
Motor Power	Approximately 200 HP class
Armature Voltage	Must match drive application
Armature Current	Must be compatible with 270 A drive rating
Field Voltage	Must match regulated field supply requirements
Field Current	Must be within field converter capability
Base Speed	Required for application
Maximum Speed	Required operating range
Feedback	Tachometer / encoder requirements
Duty Cycle	Continuous / intermittent / overload
Load Type	Constant torque / variable torque / other
Direction	One direction / reversing
Braking	Non-regenerative / regenerative requirements
Ambient Temperature	Installation environment
Enclosure	Required cabinet protection
Control Method	Analog / digital / external controller
Communication	Required network architecture
Mechanical Interface	Existing mounting and wiring

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38. Five Related Models from the Same PowerFlex DC Series

The following models are closely related to the 20P21AE270RA0NNN and are useful when selecting a different motor capacity within the same 575 VAC-class PowerFlex DC family.

Model	Rated Power	DC Current	Input Class	Operation	Frame
20P21AE067RA0NNN	50 HP / 37 kW	67.5 A	575 VAC class	Two-quadrant	B
20P21AE101RA0NNN	75 HP / 56 kW	101.3 A	575 VAC class	Two-quadrant	B
20P21AE135RA0NNN	100 HP / 75 kW	135 A	575 VAC class	Two-quadrant	B
20P21AE405RA0NNN	300 HP / 224 kW	405 A	575 VAC class	Two-quadrant	B
20P21AE540RA0NNN	400 HP / 298 kW	540 A	575 VAC class	Two-quadrant	C

These models are useful for comparing the 20P21AE270RA0NNN against lower- and higher-capacity drives.

The 135 A model, for example, is suitable for approximately 100 HP, while the 405 A model moves into approximately 300 HP territory.

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39. Same-Series Model Comparison

Model	HP	kW	DC Current	Frame	Typical Use
20P21AE067RA0NNN	50 HP	37 kW	67.5 A	B	Medium industrial DC motors
20P21AE101RA0NNN	75 HP	56 kW	101.3 A	B	Medium-power machinery
20P21AE135RA0NNN	100 HP	75 kW	135 A	B	Large machinery
20P21AE270RA0NNN	200 HP	149 kW	270 A	B	Heavy-duty machinery
20P21AE405RA0NNN	300 HP	224 kW	405 A	B	High-power industrial systems

The 20P21AE270RA0NNN sits directly between the 100 HP and 300 HP models in this group.

This makes it a logical selection when a machine’s DC motor is in the 200 HP class and its armature current requirements are around 270 A.

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40. Five Related Regenerative Models

For applications where regeneration is required, the corresponding regenerative PowerFlex DC family includes models with similar current and horsepower ratings.

Model	Rated Power	DC Current	Input Class	Operation	Frame
20P41AE067RA0NNN	50 HP / 37 kW	67.5 A	575 VAC class	Four-quadrant / regenerative	B
20P41AE101RA0NNN	75 HP / 56 kW	101.3 A	575 VAC class	Four-quadrant / regenerative	B
20P41AE135RA0NNN	100 HP / 75 kW	135 A	575 VAC class	Four-quadrant / regenerative	B
20P41AE270RA0NNN	200 HP / 149 kW	270 A	575 VAC class	Four-quadrant / regenerative	B
20P41AE405RA0NNN	300 HP / 224 kW	405 A	575 VAC class	Four-quadrant / regenerative	B

The most directly related alternative to the 20P21AE270RA0NNN is therefore the 20P41AE270RA0NNN when the application requires regenerative operation.

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41. 20P21AE270RA0NNN vs. 20P41AE270RA0NNN

These two models are particularly useful to compare because they have the same general power class.

Parameter	20P21AE270RA0NNN	20P41AE270RA0NNN
Motor Rating	200 HP	200 HP
DC Current	270 A	270 A
Input Class	575 VAC	575 VAC
Input	Three-phase	Three-phase
Converter	6-pulse	6-pulse
Operation	Two-quadrant	Regenerative / four-quadrant
Typical Application	One-direction motoring and controlled braking	Reversing and regenerative applications
Frame	B	B
Basic Application Difference	Non-regenerative	Regenerative

For a simple one-direction process machine, the non-regenerative version may be suitable.

For a machine that repeatedly reverses, lowers an overhauling load, or needs energy returned to the AC supply, a regenerative architecture should be evaluated instead.

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42. Five Popular Allen-Bradley Models for Broader Drive Applications

The following five models are popular examples from other PowerFlex families and are useful for comparison when considering whether a DC drive should be retained or whether an AC drive modernization is more appropriate.

Model	Series	Drive Type	Typical Voltage Class	General Application
25B-D017N114	PowerFlex 525	AC Variable Frequency Drive	380–480 VAC class	Compact machinery
20F11NC022JA0NNNNN	PowerFlex 753	AC Drive	380–480 VAC class	Industrial machinery
20F11NC034JA0NNNNN	PowerFlex 753	AC Drive	380–480 VAC class	Medium/high-power industrial applications
20G1ANB140JA0NNNNN	PowerFlex 755	AC Drive	380–480 VAC class	High-power industrial machinery
20G1ANC350JA0NNNNN	PowerFlex 755	AC Drive	380–480 VAC class	Heavy-duty industrial applications

These models are not direct electrical replacements for the 20P21AE270RA0NNN.

They belong to AC drive families and are therefore more relevant when a plant is considering a complete modernization from a DC motor system to an AC motor and variable-frequency drive system.

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43. Broader Product Family Comparison

Model	Series	Technology	Typical Application
20P21AE270RA0NNN	PowerFlex DC	DC motor drive	200 HP DC motor
25B-D017N114	PowerFlex 525	AC VFD	Compact machine automation
20F11NC022JA0NNNNN	PowerFlex 753	AC VFD	Industrial machine control
20F11NC034JA0NNNNN	PowerFlex 753	AC VFD	Larger industrial machines
20G1ANB140JA0NNNNN	PowerFlex 755	AC VFD	High-power industrial machinery
20G1ANC350JA0NNNNN	PowerFlex 755	AC VFD	Heavy-duty high-power applications

The PowerFlex DC model remains specifically intended for DC motor applications, whereas the PowerFlex 525, 753, and 755 families are primarily associated with AC motor control.

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44. Why a DC Drive Can Still Be Valuable

A common misconception is that every older DC motor should automatically be replaced with an AC motor.

In reality, the decision is more complicated.

An existing DC motor may still have:

• Good bearings
• Good insulation
• Good commutator condition
• Good brush condition
• Adequate mechanical life
• Suitable power capacity
• Suitable speed range
• Suitable mechanical coupling

If the motor is in good condition and the machine itself works well, replacing only the drive can sometimes be a more straightforward modernization strategy than replacing the entire motor system.

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45. Retrofit Value

The 20P21AE270RA0NNN is particularly relevant to retrofit situations involving existing 200 HP DC motors.

A typical modernization project may involve replacing:

Old DC drive

with:

Modern digital DC drive

while retaining:

• Existing DC motor
• Existing gearbox
• Existing machine mechanics
• Existing cooling system
• Existing feedback device
• Existing process equipment

This approach can reduce mechanical modifications.

However, the complete system should be evaluated before installation.

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46. Heavy-Duty Application Suitability

The 270 A rating makes this model suitable for applications where large amounts of electrical current are required.

Typical heavy-duty characteristics include:

• High starting torque
• High mechanical inertia
• Frequent load changes
• Continuous operation
• Large motor size
• Significant process load
• Stable speed requirements

The drive should nevertheless be sized based on actual motor current and duty cycle rather than horsepower alone.

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47. Cabinet Installation

Because the unit is an IP20 open-type drive, it should normally be installed within an appropriate cabinet.

The cabinet should provide:

• Mechanical protection
• Appropriate ventilation
• Electrical isolation
• Suitable grounding
• Proper cable entry
• Adequate working clearance
• Appropriate environmental protection

For a 270 A system, cable size and termination requirements also become important.

The power cables should be selected according to applicable electrical standards and actual installation conditions.

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48. Grounding and Wiring

Proper grounding is essential for both safety and reliable drive operation.

The installation should include appropriate:

• Protective earth connections
• Motor grounding
• Cabinet grounding
• Shielding where required
• Control signal separation
• Power/control cable routing

Power wiring and sensitive feedback wiring should be routed carefully to minimize electrical interference.

Encoder and tachometer feedback can be particularly sensitive to poor wiring practices.

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49. Motor Compatibility

The 20P21AE270RA0NNN should be selected only after checking the motor’s electrical specifications.

Important motor information includes:

Armature voltage

The drive must be compatible with the motor’s required armature voltage.

Armature current

The motor’s rated armature current must be compatible with the 270 A drive rating.

Field voltage

The motor field must be compatible with the available regulated field supply.

Field current

The field converter must be appropriate for the motor’s field current requirement.

Base speed

The required operating speed must be within the motor and drive operating range.

Maximum speed

The motor must not be operated above its permitted mechanical speed.

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50. Application Advantages at a Glance

Advantage	Practical Benefit
270 A output	Suitable for large DC motors
200 HP rating	Heavy industrial power capability
Digital control	Flexible configuration
Two-quadrant operation	Suitable for many one-direction applications
Regulated field	Improved field control
Six-pulse input	Conventional industrial DC architecture
Conformal coating	Additional electronic protection
IP20 open design	Suitable for cabinet installation
No HIM configuration	Useful for externally controlled systems
High-current capability	Suitable for heavy-duty machinery
PowerFlex DC architecture	Familiar to DC drive maintenance teams

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51. Detailed Parameter Table

Parameter	20P21AE270RA0NNN
Model	20P21AE270RA0NNN
Brand	Allen-Bradley
Series	PowerFlex DC
Product Type	Digital DC Drive
Rated Power	200 HP
Rated Power in kW	Approximately 149 kW
DC Output Current	270 A
AC Input	Three-phase
AC Voltage Class	500–600 VAC
Nominal System Voltage	575 VAC
Input Type	6-pulse
Motor Operation	Two-quadrant
Regeneration	Non-regenerative
Field Supply	Single-phase regulated
Enclosure	IP20
Enclosure Type	NEMA/UL Type Open
Frame	B
HIM	No HIM / Blank Plate
Communication	None-Standard
Conformal Coating	Yes
Approx. Height	311 mm
Approx. Width	388 mm
Approx. Depth	350 mm
Approx. Drive Weight	29.5 kg
Approx. Packaged Weight	31.5 kg
Approx. AC Line Current	220.6 A
Associated Line Reactor	1321-3RB250-B
Main Application	Industrial DC motor control
Typical Motor Class	200 HP DC motor

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52. Five Same-Series Models – Detailed Comparison

Model	HP	kW	DC Current	Frame	Operation	Typical Position in Range
20P21AE067RA0NNN	50	37	67.5 A	B	Two-quadrant	Lower power
20P21AE101RA0NNN	75	56	101.3 A	B	Two-quadrant	Lower-medium power
20P21AE135RA0NNN	100	75	135 A	B	Two-quadrant	Medium power
20P21AE405RA0NNN	300	224	405 A	B	Two-quadrant	Higher power
20P21AE540RA0NNN	400	298	540 A	C	Two-quadrant	High power

The 20P21AE270RA0NNN fills an important position between the 100 HP and 300 HP versions.

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53. Five Same-Brand Models – Detailed Comparison

Model	Series	Technology	Voltage Class	General Application
25B-D017N114	PowerFlex 525	AC VFD	380–480 VAC class	Compact machinery
20F11NC022JA0NNNNN	PowerFlex 753	AC VFD	380–480 VAC class	Industrial motor control
20F11NC034JA0NNNNN	PowerFlex 753	AC VFD	380–480 VAC class	Medium/high-power machinery
20G1ANB140JA0NNNNN	PowerFlex 755	AC VFD	380–480 VAC class	High-power machinery
20G1ANC350JA0NNNNN	PowerFlex 755	AC VFD	380–480 VAC class	Heavy-duty industrial applications

These models are included as broader same-brand alternatives rather than direct substitutes.

A direct replacement decision requires a comparison of motor type, voltage, current, speed range, feedback, braking requirements, communications, and mechanical characteristics.

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54. Suitable Industries

The 20P21AE270RA0NNN can be relevant to many industrial sectors.

Industry	Potential Applications
Paper	Roll drives, winders, unwinders
Printing	Presses, rollers, web handling
Steel	Roll drives, material handling
Textile	Spinning, winding, processing
Mining	Conveyors and material handling
Manufacturing	Production machinery
Water Processing	Large pump systems
Chemical Processing	Process machinery
Plastics	Extrusion and material handling
Metal Processing	Roll and tension systems
General Industrial	Large DC motor systems

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55. Product Selection Checklist

Before purchasing or installing the 20P21AE270RA0NNN, the following items should be checked.

Check Item	Requirement
Motor Type	DC motor
Motor Power	Approximately 200 HP class
Motor Current	Compatible with 270 A drive
Motor Armature Voltage	Must be verified
Motor Field Voltage	Must be verified
Motor Field Current	Must be verified
Input Supply	Compatible three-phase AC system
Input Voltage	Compatible with 500–600 VAC class
Operation	Suitable for two-quadrant operation
Regeneration	Not required
Feedback	Verify tachometer/encoder requirements
Cabinet	Suitable IP20 drive enclosure
Cooling	Adequate airflow
Line Reactor	Verify system requirements
Control	Verify external control signals
Wiring	Verify power and control wiring
Environment	Suitable for conformal-coated drive
Mechanical Space	Minimum drive dimensions plus service clearance

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56. Overall Product Advantages

The Allen-Bradley 20P21AE270RA0NNN is a high-current PowerFlex DC drive designed for large industrial DC motor applications.

Its main strengths are its 270 A DC current capacity, 200 HP motor rating, regulated field supply, digital control architecture, two-quadrant operation, and industrial cabinet-oriented construction.

It is particularly relevant where a production machine already uses a large DC motor and requires a modern digital drive controller.

The 20P21AE270RA0NNN is not simply a small machine drive scaled upward. It is intended for substantially larger industrial equipment where motor current, thermal management, cabinet design, braking behavior, and system protection all become important engineering considerations.

Its 200 HP capability makes it suitable for a wide range of large industrial machines, especially conveyors, winders, paper machinery, printing systems, textile machinery, material-handling equipment, pumps, fans, and process machinery.

The two-quadrant architecture makes it appropriate for applications that do not require full regenerative operation. When regeneration or frequent load reversal is required, the corresponding regenerative PowerFlex DC configuration should instead be considered.

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57. Final Product Summary

Item	Final Specification
Product	PowerFlex DC Drive
Model	20P21AE270RA0NNN
Brand	Allen-Bradley
Series	PowerFlex DC
Motor Rating	200 HP
Power Rating	Approximately 149 kW
DC Current	270 A
Input	Three-phase AC
Input Voltage Class	500–600 VAC
Typical Input	575 VAC
Input Type	6-pulse
Motor Operation	Two-quadrant
Regenerative	No
Field Supply	Single-phase regulated
Enclosure	IP20 / NEMA/UL Type Open
Frame	B
Coating	Conformal coated
HIM	Blank plate / No HIM
Communication Module	None
Height	Approximately 311 mm
Width	Approximately 388 mm
Depth	Approximately 350 mm
Drive Weight	Approximately 29.5 kg
Packaged Weight	Approximately 31.5 kg
Typical Applications	Conveyors, paper, printing, winding, textile, pumps, fans, material handling and industrial process equipment

The 20P21AE270RA0NNN is therefore best understood as a 200 HP, 270 A, 575 VAC-class PowerFlex DC drive for large industrial DC motor systems. Its combination of high current capacity, regulated field control, digital regulation, two-quadrant operation, and cabinet-oriented construction makes it a practical model for large DC motor control and modernization projects where the existing motor and mechanical system are to remain in service.