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20P21AD412RA0NNN PowerFlex DC Drive

Detailed Product Specifications, Product Introduction, Applications, Advantages, Series Information and Related Model Recommendations

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1. Product Basic Information

The 20P21AD412RA0NNN is a high-power industrial DC drive designed for large DC motor control applications. It belongs to the PowerFlex DC product series and is configured for a 480 VAC, three-phase input, 412 A output, and 250 HP motor power class.

This model is a non-regenerative, two-quadrant DC drive, making it particularly suitable for industrial machinery where controlled acceleration, deceleration, speed regulation and torque control are required, but continuous regenerative braking is not the primary operating requirement.

The drive uses a 6-pulse power-conversion configuration and incorporates a regulated field supply. It is designed for cabinet installation and uses an IP20, NEMA/UL Type Open enclosure arrangement with conformal coating.

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2. Brand and Product Series

The product belongs to the PowerFlex DC family, which is specifically intended for industrial DC motor applications.

Compared with a conventional AC variable-frequency drive, a DC drive is designed around the characteristics of a DC motor, including armature current control, field control and DC motor feedback.

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3. Detailed Technical Specifications

Note: The weight is approximately 32.6 kg based on the commonly specified 71.9 lb unit weight. Mechanical dimensions can vary depending on the exact dimensional reference being used, so cabinet fabrication should be based on the applicable mechanical drawing rather than relying only on a catalog approximation.

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4. Product Introduction

The 20P21AD412RA0NNN is a high-current DC motor drive intended for demanding industrial applications.

With a rated output current of 412 A and a motor rating of approximately 250 HP / 187 kW, it is designed for significantly larger motor systems than compact and medium-capacity DC drives.

The drive regulates the electrical power supplied to the DC motor armature while also providing controlled field operation. This allows the motor to be operated with controlled speed, acceleration, deceleration and torque.

The product is particularly relevant to industrial equipment that was originally designed around DC motors.

Many large production machines have historically used DC motors because of their excellent low-speed torque characteristics, straightforward speed regulation and suitability for high-power mechanical systems.

In such installations, the motor and mechanical transmission can remain mechanically sound for many years even when the original electronic control equipment becomes obsolete.

A high-power DC drive such as the 20P21AD412RA0NNN can therefore serve as an important component in a modernization or retrofit project.

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5. 412 A High-Current Design

One of the most important characteristics of the 20P21AD412RA0NNN is its 412 A DC output rating.

This places the product in the high-power section of the PowerFlex DC range.

The high current capacity allows the drive to operate large DC motors used in demanding production machinery.

The actual motor current should always be checked against the motor nameplate and application duty.

A motor rated at 250 HP is not automatically suitable simply because the drive is rated at 250 HP. Armature voltage, armature current, field voltage, field current, speed range and duty cycle must all be considered.

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6. 250 HP / 187 kW Power Class

The drive is rated for approximately 250 HP, corresponding to approximately 187 kW.

This power level is suitable for substantial industrial machinery.

Typical equipment in this range can include:

• Large conveyors
• Heavy-duty material handling systems
• Paper-processing machines
• Large winding machines
• Unwinding machines
• Metal-processing equipment
• Large printing machinery
• Industrial rolling equipment
• Heavy machine tools
• Large process machinery
• High-power production lines

The 250 HP rating provides a significant amount of motor-control capacity while remaining within the Frame B section of the product range.

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7. 480 VAC Three-Phase Input

The 20P21AD412RA0NNN is configured for a 480 VAC three-phase input.

The three-phase industrial power supply is converted through a six-pulse power stage into controlled DC output power for the motor.

For an installation of this size, the electrical distribution system should be evaluated carefully.

Important considerations include:

At 412 A, this is not a small control device. Proper power-distribution engineering is important for safe and reliable operation.

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8. Six-Pulse Conversion

The drive uses a six-pulse input converter.

Six-pulse conversion is a conventional and widely used architecture for industrial DC drives.

The three-phase AC supply is converted into controlled DC power for the motor armature.

This configuration is particularly appropriate for large industrial installations where the DC motor is already part of the machine.

The six-pulse arrangement should also be considered when evaluating input power quality and harmonic performance.

For large installations, the complete electrical system may require additional consideration of transformer impedance, line reactors, harmonic effects, protection and power quality.

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9. Two-Quadrant Operation

The 20P21AD412RA0NNN is a two-quadrant, non-regenerative drive.

This means it is intended for applications where the motor operates in the required forward torque/speed regions without requiring continuous regenerative energy transfer back into the AC supply.

This configuration is suitable for many conventional industrial applications.

Examples include:

• Conveyors
• Processing machinery
• Paper machines
• General winding applications
• Material-handling systems
• Large production equipment
• Industrial machine tools

However, applications involving substantial regenerative braking should be evaluated carefully.

If the motor must frequently decelerate a high-inertia load, reverse rapidly, or absorb energy from an overhauling load, a regenerative configuration may be more appropriate.

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10. Regulated Field Supply

The product incorporates a single-phase regulated field supply.

Field control is an important part of DC motor operation.

The field establishes the magnetic flux required for motor operation, while armature control manages motor current and therefore contributes strongly to torque production.

A regulated field system can provide controlled operation over different speed ranges.

It is particularly relevant to applications where the motor needs to operate above base speed using field weakening.

The actual motor field voltage and field current must be checked before selecting the drive for a particular motor.

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11. Feedback Capability

The PowerFlex DC platform supports feedback arrangements such as DC tachometer and encoder feedback.

Feedback can significantly improve speed regulation.

In a feedback-controlled system, the drive receives information about actual motor speed and compares it with the desired speed.

This allows the control system to compensate for load changes and other operating variations.

Feedback can be particularly useful for:

• Winding machinery
• Paper machinery
• Printing equipment
• Converting machinery
• Speed synchronization
• Precision material handling
• Large process lines
• Multi-motor systems

For retrofit applications, it is important to identify the exact feedback device already installed on the machine.

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12. IP20 Enclosure

The 20P21AD412RA0NNN uses an IP20, NEMA/UL Type Open enclosure arrangement.

This means the drive is intended to be installed inside an appropriate electrical cabinet or enclosure.

It is not intended to function as an outdoor weatherproof drive.

The cabinet should protect the drive from:

• Water
• Excessive humidity
• Conductive dust
• Corrosive contamination
• Mechanical damage
• Foreign objects
• Excessive ambient temperature

Adequate airflow must also be maintained.

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13. Conformal Coating

The model includes a conformal coating configuration.

Conformal coating provides additional protection for electronic components against certain environmental stresses.

This can be valuable in industrial environments where the electrical enclosure may be exposed to:

• Dust
• Humidity
• Industrial contaminants
• Chemical vapors
• Condensation risks

Conformal coating does not eliminate the need for an appropriate enclosure.

Good cabinet design and environmental control remain essential.

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14. Air-Cooled Construction

The drive is air cooled.

A 250 HP DC drive can generate considerable heat during continuous operation.

The cabinet therefore needs sufficient ventilation and thermal capacity.

The following factors should be considered during cabinet design:

• Ambient temperature
• Internal cabinet temperature
• Drive losses
• Cooling-air flow
• Fan capacity
• Ventilation path
• Filter condition
• Dust accumulation
• Clearance around the drive
• Heat generated by other equipment

A cabinet should never be selected based solely on whether the drive physically fits inside it.

Thermal performance is equally important.

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15. Product Applications

15.1 Large Conveyor Systems

The 20P21AD412RA0NNN can be used for large DC-motor-driven conveyor systems.

A large conveyor can have considerable inertia, especially when carrying heavy material.

Controlled acceleration helps prevent sudden mechanical loading.

This can reduce stress on:

• Conveyor belts
• Gearboxes
• Couplings
• Bearings
• Drive shafts
• Mechanical brakes

For conveyors with significant downhill loads, regenerative requirements must be evaluated separately.

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15.2 Paper Machinery

Large paper-processing equipment is one of the applications where DC motor control can be particularly useful.

Typical applications include:

• Roll drives
• Winder drives
• Unwinder drives
• Coating equipment
• Web handling
• Paper processing lines
• Converting systems

Stable speed and torque are important because variations in motor operation can affect product quality and material tension.

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15.3 Winding Equipment

Winding machinery can require precise control of motor speed and torque.

As the diameter of the material roll changes, the motor operating requirements can change considerably.

The drive can be incorporated into a broader control system that manages:

• Motor speed
• Torque
• Acceleration
• Deceleration
• Tension
• Diameter compensation
• Feedback

For high-performance winding applications, the complete control system should be designed around the motor, mechanical system and feedback device rather than selecting the drive solely by horsepower.

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15.4 Unwinding Systems

Unwinding machines can place special requirements on braking and tension control.

A non-regenerative drive may be suitable for some configurations, but the mechanical and electrical braking system must be examined carefully.

Where the load can drive the motor during deceleration, regenerative operation may be required.

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15.5 Metal-Processing Machinery

The high current capacity makes the product suitable for large industrial metal-processing equipment.

Potential applications include:

• Material handling
• Roller systems
• Processing lines
• Large winding systems
• Heavy-duty production equipment
• High-power mechanical drives

The high torque capability of DC motors can be useful in heavy industrial machinery.

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15.6 Printing Machinery

Large printing and converting machines can require coordinated motor speed.

A DC drive can provide stable speed control and can be integrated with feedback and external machine-control systems.

This can help maintain consistent material movement through the machine.

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15.7 Large Machine Tools

Large machine tools may use high-power DC motors for spindle or auxiliary motion applications.

The drive can provide controlled:

• Starting
• Acceleration
• Running speed
• Deceleration
• Torque
• Stopping

The exact motor characteristics should be reviewed before selecting the drive.

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16. Main Product Advantages

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17. Advantages for Industrial Retrofit

The strongest practical advantage of the 20P21AD412RA0NNN is its suitability for large DC motor modernization projects.

An older production machine may contain a large DC motor that remains mechanically sound.

Replacing the entire motor system can involve extensive mechanical engineering.

A drive replacement may allow the existing motor and mechanical transmission to remain in service after compatibility has been verified.

This can potentially reduce:

• Mechanical modification
• Installation work
• Engineering effort
• Machine downtime
• Spare-parts changes
• Operator retraining

For large production machinery, minimizing downtime can be particularly important.

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18. Five Same-Series or Closely Related Models

The following models are useful for comparison because they belong to the same PowerFlex DC family and cover nearby power/current ratings.

The 20P21AD330RA0NNN is the closest lower-power option to the target model in this group, while the 20P21AD495RA0NNN moves into the next larger power range.

The 20P21AD412RA0NNN itself is rated at 412 A / 250 HP / approximately 187 kW, placing it directly between the 330 A and 495 A configurations.

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19. Five Regenerative Models for Related Applications

If an application requires regenerative braking or four-quadrant operation, the corresponding regenerative product family is worth considering.

These are not direct drop-in replacements for the target model.

The principal reason for considering them is the different operating requirement.

A regenerative DC drive is more appropriate when the machine must frequently absorb and return braking energy.

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20. Comparison of Nearby PowerFlex DC Models

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21. Five Popular Models From the Same Brand

The following models represent commonly used products from the same industrial automation portfolio.

They are not direct replacements for the 20P21AD412RA0NNN. They are included as alternative products for different machine-control requirements.

These products serve different purposes.

The PowerFlex 525 and PowerFlex 755 families are primarily associated with AC motor control, while CompactLogix and ControlLogix products are programmable-control platforms.

For an existing 250 HP DC motor, a PowerFlex DC drive remains the more directly relevant product category.

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22. Application Comparison

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23. Motor Compatibility Considerations

Before installing the 20P21AD412RA0NNN, the motor nameplate should be reviewed carefully.

The following parameters are particularly important.

The drive rating should be selected based on the actual motor operating conditions rather than horsepower alone.

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24. Cabinet Installation Requirements

Because the drive is an IP20 open-type product, it should be installed inside a suitable electrical cabinet.

The cabinet should provide sufficient space for:

• Drive mounting
• Power wiring
• Control wiring
• Field wiring
• Feedback wiring
• Ventilation
• Maintenance access
• Cable bending radius
• Heat dissipation
• Protective devices

The cabinet should not be designed with the drive pressed directly against other heat-producing components.

Adequate clearance is necessary to maintain proper airflow.

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25. Dimensions and Mechanical Installation

The model is identified as a Frame B PowerFlex DC drive.

For general planning purposes, the drive has a substantial industrial cabinet footprint and approximately 451 mm depth in commonly referenced dimensional data.

A practical engineering specification can therefore be presented as follows:

For actual panel fabrication, the mechanical drawing should be treated as the controlling document.

The values above are intended for product-selection and preliminary engineering rather than final cabinet manufacturing.

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26. Weight

The approximate unit weight of the 20P21AD412RA0NNN is:

32.6 kg

This corresponds to approximately 71.9 lb.

The actual shipping weight will be higher because packaging materials, documentation and protective packaging are not included in the bare-unit weight.

For cabinet structural calculations, the installed weight of the drive should be considered together with:

• Input protection
• Disconnects
• Contactors
• Reactors
• Terminal blocks
• Control equipment
• PLC equipment
• Cooling equipment
• Wiring

The cabinet mounting structure should therefore not be designed around the drive weight alone.

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27. Why Choose the 20P21AD412RA0NNN?

The 20P21AD412RA0NNN is particularly attractive when the application has the following characteristics:

• Existing DC motor
• Approximately 250 HP motor
• Approximately 187 kW motor
• 480 VAC industrial power supply
• High armature current requirement
• Two-quadrant operation
• No continuous regeneration requirement
• Need for controlled speed
• Need for controlled acceleration
• Need for controlled deceleration
• Need for regulated motor field
• Industrial cabinet installation
• Existing encoder or tachometer feedback

When these conditions are present, the model provides a strong technical match for the application.

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28. Advantages Compared With a Lower-Power DC Drive

A lower-current model may be suitable for smaller motors, but using a lower-rated drive for a 250 HP motor can create limitations.

The 412 A model provides additional current capacity appropriate for larger motor systems.

Compared with a 250 A or 330 A model, the 412 A version is better suited to motors requiring higher armature current.

The important point is that the selected drive must still match the actual motor nameplate and application duty.

Oversizing and undersizing both have consequences.

An undersized drive may not meet the required continuous or overload current.

An oversized drive can increase equipment cost and may require different cabinet, protection and wiring arrangements.

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29. Recommended Related Models by Power

This progression is useful when selecting a drive based on motor current and power.

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30. Non-Regenerative and Regenerative Selection

The 20P21AD412RA0NNN is the appropriate type when the machine does not require regenerative operation.

If the load drives the motor during braking, the application should be evaluated carefully before using a non-regenerative drive.

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31. Product Advantages in Detail

High Current Capacity

The 412 A output rating gives the drive substantial capacity for large DC motors.

This makes the product appropriate for heavy industrial applications where a smaller drive would not provide sufficient current.

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Large Motor Compatibility

The 250 HP / 187 kW class allows the drive to be used with large motors commonly found in heavy industrial machinery.

This makes it more suitable for production-scale equipment than low-power DC drives.

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Precise Speed Control Potential

With suitable feedback and correct tuning, the drive can provide stable motor-speed regulation.

This is useful for processes where motor-speed variation can affect production quality.

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Controlled Acceleration

Controlled acceleration can reduce mechanical stress during startup.

This is particularly valuable for machines with:

• Large rotating masses
• Long conveyors
• Heavy rolls
• Large gearboxes
• High-inertia mechanical systems

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Controlled Deceleration

The drive can provide controlled deceleration within the limitations of its non-regenerative operating configuration.

Where regeneration is not required, this can simplify the drive system.

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Regulated Field Control

The field supply allows the motor field to be controlled rather than simply relying on an uncontrolled field circuit.

This is important for wide-speed-range DC motor applications.

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Retrofit Friendly

The product can be considered for modernization of existing DC motor equipment.

This can be useful when the mechanical portion of the machine remains in good condition.

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Industrial Construction

The IP20 open-type configuration is suitable for integration into industrial electrical cabinets.

The conformal-coated version provides an additional level of protection for the electronics in suitable industrial environments.

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32. Typical Industries

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33. Recommended Five Same-Series Models

For users purchasing or comparing products within the same PowerFlex DC range, the following five models are particularly relevant.

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34. Recommended Five Same-Brand Popular Models

These products are popular within different areas of industrial automation, but they should not be regarded as direct replacements for the 20P21AD412RA0NNN.

The target product is a high-power DC motor drive, while the other products cover AC motor control and programmable automation.

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35. Overall Technical Evaluation

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36. Final Product Summary

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37. Conclusion

The 20P21AD412RA0NNN is a high-capacity industrial DC drive designed for large motor applications where high current, stable speed regulation and controlled motor operation are required.

With a 412 A output rating, 250 HP motor rating, and approximately 187 kW power class, it is positioned for heavy-duty machinery rather than small or general-purpose motor applications.

Its 480 VAC three-phase input, six-pulse power-conversion structure, regulated field supply, feedback capability, IP20 cabinet-oriented construction and conformal-coated configuration make it suitable for demanding industrial environments when properly installed.

The product is particularly attractive for modernization projects involving existing DC motors.

For machinery that already has a mechanically sound 250 HP DC motor, replacing an aging drive can potentially extend the useful life of the machine while avoiding a complete mechanical redesign.

The product is especially well suited to large conveyors, paper machinery, winding and unwinding systems, printing and converting machinery, metal-processing equipment, material-handling systems and other high-power industrial machines.

The most important selection point is the 412 A current rating. The motor’s actual armature current, armature voltage, field voltage, field current, speed range, feedback device and duty cycle should all be checked before final selection.

Another important consideration is that the 20P21AD412RA0NNN is a two-quadrant, non-regenerative configuration. If the application has frequent regenerative braking, high-inertia deceleration, overhauling loads or frequent forward/reverse operation, a regenerative version should be evaluated instead.

For preliminary product identification, the key specifications are PowerFlex DC, 480 VAC, three-phase, 412 A, 250 HP, approximately 187 kW, six-pulse input, two-quadrant non-regenerative operation, regulated field supply, IP20 enclosure, Frame B, air cooling, conformal coating, approximately 451 mm depth and approximately 32.6 kg unit weight.

For final equipment installation, the actual motor nameplate and mechanical installation requirements should take priority over general catalog selection data.