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1. Product Overview

The Allen-Bradley 21AD027A3AYNAEC0NNNN-ND-B0-C1-P1 is a PowerFlex 70 configured adjustable-frequency AC drive designed for industrial motor speed control, controlled acceleration and deceleration, process automation, and general-purpose variable-speed machinery.

It belongs to the PowerFlex 70 Configured Drive family and is based on the 480 VAC, three-phase PowerFlex 70 platform.

The important difference between this model and the smaller 21AD014 is the higher current and power class. The corresponding 480 VAC PowerFlex 70 27 A rating is a Frame D drive with a 20 HP normal-duty rating and a 15 HP heavy-duty rating. The published technical data lists 27 A continuous output current, with higher short-term current capability for overload conditions.

The long catalog number is significant because this is a configured product. The complete ordering number identifies not only the basic 27 A PowerFlex 70 drive but also the selected duty, bypass, control-power, protection, feedback, I/O, and related configuration options.

For industrial machinery requiring more motor capacity than the 14 A PowerFlex 70 class, the 21AD027 provides a substantial step upward while remaining within the PowerFlex 70 product family.

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2. Brand and Product Series

Item	Description
Brand	Allen-Bradley
Product Family	PowerFlex
Product Series	PowerFlex 70
Product Type	Configured Adjustable Frequency AC Drive
Model / Catalog Number	21AD027A3AYNAEC0NNNN-ND-B0-C1-P1
Voltage Class	480 VAC
Input Phase	Three-phase
Output Current	27 A
Normal-Duty Motor Rating	20 HP / approximately 15 kW
Heavy-Duty Motor Rating	15 HP / approximately 11 kW
Frame Size	D
Enclosure Class	IP20 / NEMA/UL Type 1 style
Control Type	Variable-frequency AC motor control
Feedback Configuration	No encoder feedback in the specified configuration
Brake Function	Brake IGBT configuration
Internal Brake Resistor	Not included
Bypass	No bypass
Control Power	Drive-only control power
Input Protection	No integrated input protection under P1
I/O	Enhanced 24 V DC I/O
Typical Application	Industrial variable-speed motor control

The PowerFlex 70 rating table identifies the 480 VAC 20AD027 drive as Frame D, with a 20 HP normal-duty rating, 15 HP heavy-duty rating, and 27 A continuous output rating.

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3. Main Technical Parameters

Parameter	Specification
Model / Catalog Number	21AD027A3AYNAEC0NNNN-ND-B0-C1-P1
Brand	Allen-Bradley
Series	PowerFlex 70
Product Type	Configured AC Drive
Input Voltage	480 VAC class
Input Phase	3 Phase
Output Current	27 A
Normal-Duty Rating	20 HP
Normal-Duty Power	Approximately 15 kW
Heavy-Duty Rating	15 HP
Heavy-Duty Power	Approximately 11 kW
Continuous Output Current	27 A
1-Minute Output Current	Approximately 33 A
3-Second Output Current	Approximately 44 A
Frame Size	D
Enclosure	IP20 / NEMA/UL Type 1
Frequency Class	50/60 Hz
Motor Type	Three-phase AC motor
Feedback	No encoder feedback
Brake IGBT	Included
Internal Brake Resistor	Not included
Bypass	No bypass
Control Power	Drive-only control power
Input Protection	P1 – no integrated input protection
I/O	Enhanced 24 V DC I/O
Communication	No additional communication module indicated in the specified configuration
Mounting	Panel / cabinet mounting
Cooling	Integral forced-air cooling
Frame	D
Approximate Height	350 mm
Approximate Width	220 mm
Approximate Depth	169 mm
Approximate Dimensions	350 × 220 × 169 mm
Approximate Weight	9.25 kg
Typical Motor Class	20 HP normal duty
Main Function	Variable-speed AC motor control

The 480 VAC 27 A PowerFlex 70 rating provides 20 HP normal-duty and 15 HP heavy-duty operation. The technical data also lists 27 A continuous output, approximately 33 A for one-minute overload and approximately 44 A for three-second overload.

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4. Dimensions and Weight

The 21AD027 moves into Frame D, which is an important mechanical difference compared with the smaller 11 A and 14 A Frame C models.

The approximate Frame D dimensions are 350 × 220 × 169 mm, with an approximate drive weight of 9.25 kg.

Mechanical Parameter	Specification
Model / Catalog Number	21AD027A3AYNAEC0NNNN-ND-B0-C1-P1
Frame	D
Height	Approximately 350 mm
Width	Approximately 220 mm
Depth	Approximately 169 mm
Height	Approximately 13.78 in
Width	Approximately 8.66 in
Depth	Approximately 6.65 in
Approximate Drive Weight	9.25 kg
Approximate Weight	20.4 lb
Mounting Type	Panel / cabinet
Standard Enclosure	IP20 / NEMA/UL Type 1

The Frame D mechanical envelope is substantially larger than the Frame C package used by the lower-current PowerFlex 70 models. The published technical data gives approximately 350 mm × 219.9 mm × 169 mm for the Frame D class, with an approximate 9.25 kg drive weight.

For actual cabinet fabrication, additional space must be allowed for power wiring, control wiring, cable bending radius, ventilation, service access, and surrounding components.

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5. Product Introduction

The Allen-Bradley 21AD027 is designed to regulate the speed and operating behavior of three-phase AC motors in industrial equipment.

A motor connected directly to a fixed-frequency AC supply normally operates at a relatively fixed speed. A variable-frequency drive changes the electrical frequency and voltage supplied to the motor, allowing the machine to operate at different speeds.

This is useful when the mechanical process does not require constant motor speed.

For example, a conveyor may operate at several production speeds. A pump may need to respond to changing process demand. A fan may need to provide different airflow levels. A mixer may require a controlled startup and adjustable operating speed.

The 21AD027 provides the drive capacity needed for applications around the 20 HP normal-duty class, making it considerably more capable than the 10 HP-class 21AD014.

The model is particularly relevant when a machine requires more current but the application still fits within the conventional PowerFlex 70 variable-speed architecture.

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6. 480 VAC Three-Phase Design

The 21AD027 is part of the 480 VAC three-phase PowerFlex 70 drive class.

Electrical Item	Specification
Model / Catalog Number	21AD027A3AYNAEC0NNNN-ND-B0-C1-P1
Input Voltage Class	480 VAC
Input Configuration	Three-phase
Frequency	50/60 Hz class
Output Current	27 A
Normal-Duty Power	20 HP / approximately 15 kW
Heavy-Duty Power	15 HP / approximately 11 kW
Frame	D
Application	Industrial AC motor control

The actual motor voltage and full-load current should always be checked before selecting the drive for a particular motor.

The 20 HP rating is a useful reference point, but motor current remains one of the most important parameters in actual drive selection.

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7. 27 A Output Rating

The 27 A output-current rating is the defining electrical characteristic of the 21AD027.

The corresponding PowerFlex 70 480 VAC model provides:

• 27 A continuous output
• Approximately 33 A for one-minute overload
• Approximately 44 A for three-second overload

The published rating table associates the model with 20 HP normal duty and 15 HP heavy duty.

This places the drive in a useful medium-power industrial category.

It is large enough for many production machines while remaining substantially smaller than the high-power PowerFlex 70 frames.

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8. Normal-Duty and Heavy-Duty Ratings

The drive provides two important motor-power classifications.

Duty Rating	Motor Rating
Normal Duty	20 HP / approximately 15 kW
Heavy Duty	15 HP / approximately 11 kW

Normal-duty operation is appropriate for applications where the motor does not require the higher overload capability associated with heavy-duty operation.

Heavy-duty applications can include machines with demanding acceleration, higher starting torque, repeated overloads, or severe load cycles.

The distinction is important when selecting a drive.

A 15 HP motor with a high-inertia mechanical load may require more drive capacity than a 15 HP motor operating a relatively easy fan load.

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9. Output Overload Capability

One of the useful characteristics of the 27 A drive class is its short-term overload capability.

Output Condition	Approximate Current
Continuous	27 A
1 Minute	33 A
3 Seconds	44 A

These figures demonstrate why the drive can handle temporary increases in motor demand without immediately being treated as a larger continuous-current drive.

However, short-term overload capacity should not be interpreted as permission to operate the drive continuously above its rated current.

The motor, mechanical load, ambient temperature, and operating cycle all influence the appropriate drive selection.

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10. Brake IGBT Configuration

The specified catalog configuration includes a brake IGBT.

This provides a means of connecting an external dynamic-braking resistor when the application requires controlled dissipation of regenerated energy.

When an AC motor decelerates, it can temporarily operate as a generator.

The energy returned from the motor can increase the drive’s DC-bus voltage.

If rapid deceleration is required, a braking resistor can dissipate this energy.

This is useful for machines such as:

• High-inertia conveyors
• Roll systems
• Material-handling equipment
• Certain winding machines
• High-speed rotating equipment
• Machines requiring frequent stopping
• Machinery with short deceleration times

The brake IGBT itself does not mean that a complete external braking system is automatically included.

The resistor must be selected according to the actual mechanical energy and braking duty cycle.

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11. No Internal Brake Resistor

The catalog configuration does not include an internal brake resistor.

This allows the braking system to be designed according to the actual application.

A machine that stops occasionally may require relatively little braking energy.

A machine that repeatedly accelerates and decelerates may require substantially more braking capacity.

The braking resistor therefore needs to be evaluated according to:

• Motor power
• Load inertia
• Maximum speed
• Deceleration time
• Number of braking cycles
• Duty cycle
• Allowable resistor temperature

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12. No Bypass Configuration

The B0 option represents a no-bypass configuration.

The drive is therefore intended to remain the primary motor-control device.

This is suitable for many modern production machines where variable-speed control is an essential part of the process.

Applications that require an emergency or maintenance bypass arrangement may need additional equipment or a different configured-drive option.

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13. C1 Drive-Only Control Power

The C1 configuration indicates drive-only control power.

This means the configured package is designed around the drive itself rather than a more elaborate bypass/control-power architecture.

This can simplify control-panel construction.

The control-power requirements should nevertheless be considered separately from the main 480 VAC power circuit.

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14. P1 Input Protection

The P1 configuration indicates that integrated input protection is not included as part of the configured drive package.

The upstream electrical installation therefore needs suitable protective equipment.

Depending on the installation, this may involve:

• Fuses
• Circuit breaker
• Disconnect
• Motor protection
• Panel-level branch-circuit protection

The exact protective equipment must be selected according to the installation design and applicable electrical requirements.

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15. Enhanced 24 V DC I/O

The configuration uses enhanced 24 V DC I/O.

This provides a practical interface between the drive and an industrial control system.

Typical signals can include:

• Run
• Stop
• Forward
• Reverse
• External enable
• Speed reference
• Fault
• Drive ready
• Status
• Process-control signals

This allows the drive to operate as part of a larger PLC-based machine-control system.

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16. No Encoder Feedback

The specified configuration does not include encoder feedback.

For many industrial applications, this is sufficient.

A conveyor, fan, pump, or blower often does not require a physical encoder.

The drive can control motor speed using its standard motor-control capabilities.

More demanding applications may require feedback.

Examples include:

• Precise low-speed operation
• Tight speed regulation
• Precision winding
• Position control
• High-performance motion

In those cases, a different feedback configuration or drive family may be more appropriate.

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17. IP20 / NEMA/UL Type 1 Construction

The standard PowerFlex 70 panel-mount construction is associated with IP20 / NEMA/UL Type 1 protection.

This means the drive is intended for installation inside a suitable industrial enclosure or controlled environment.

It is not a sealed outdoor drive.

If the installation involves:

• Water spray
• Oil mist
• Heavy dust
• Corrosive chemicals
• Conductive contamination
• High humidity
• Outdoor exposure

then the enclosure and environmental protection need to be designed accordingly.

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18. Main Product Applications

Conveyor Systems

The 21AD027 is well suited to many industrial conveyor systems.

A 20 HP-class motor can drive a considerably larger conveyor system than the smaller 5–10 HP drive classes.

Variable-frequency control allows the conveyor to start gradually, reach operating speed smoothly, and operate at different production speeds.

Controlled acceleration can reduce stress on:

• Belts
• Chains
• Gearboxes
• Couplings
• Bearings
• Mechanical frames

The 27 A drive also provides useful overload capability for applications where the conveyor load changes during production.

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Pumps

The 21AD027 can be used for medium-sized industrial pumps.

Variable-speed control allows motor speed to be adjusted according to process demand.

Applications may include:

• Process pumps
• Cooling-water pumps
• Circulation pumps
• Industrial water systems
• Fluid-transfer equipment
• Process-control pumping systems

The pump’s required speed range and motor current should be checked before final selection.

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Fans

Large industrial fans can require motors in the 10–20 HP range.

The 21AD027 provides a suitable drive class for many such applications.

The fan speed can be adjusted according to ventilation requirements.

This can be useful in:

• Factory ventilation
• Process exhaust
• Dust collection
• Industrial cooling
• Air-handling systems

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Blowers

Industrial blowers can impose more demanding starting and operating conditions than simple fans.

The drive can provide controlled acceleration and variable operating speed.

The actual blower load curve should be evaluated when determining whether normal-duty or heavy-duty operation is appropriate.

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Mixers

The 20 HP normal-duty rating makes this drive useful for many medium-sized mixers.

Mixer torque can change as the material inside the vessel changes.

The starting condition can also be considerably more demanding than the steady-state condition.

For this reason, the 15 HP heavy-duty rating may be more relevant than the 20 HP normal-duty rating for some applications.

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Material Handling

Material-handling equipment is another strong application area.

The drive can control:

• Conveyors
• Feeders
• Rollers
• Transfer systems
• Sorting mechanisms
• Production-line material movement

The ability to control acceleration and speed can be particularly useful where products must be moved without sudden mechanical movement.

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Packaging Equipment

Packaging lines frequently use multiple motors.

The 21AD027 can operate as one of the main motor drives in larger machines.

It can control conveyors, rollers, feeders, and other mechanisms where 20 HP-class motor power is required.

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Process Machinery

The drive is also appropriate for many industrial processing systems.

Examples include:

• Rollers
• Feeders
• Processing lines
• Material-transfer equipment
• Production machinery
• Industrial mixers
• Auxiliary process drives

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19. Main Product Advantages

1. 20 HP Normal-Duty Capability

The 20 HP normal-duty rating provides a substantial increase over smaller PowerFlex 70 models.

This allows the drive to control larger industrial machines.

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2. 15 HP Heavy-Duty Capability

The 15 HP heavy-duty rating provides useful capacity for applications requiring more demanding overload performance.

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3. 27 A Continuous Output

The 27 A current rating provides a useful selection point for medium-power industrial motors.

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4. Short-Term Overload Capability

The approximately 33 A one-minute and 44 A three-second current levels provide additional temporary overload capacity.

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5. 480 VAC Three-Phase Compatibility

The drive is designed for industrial 480 VAC three-phase applications.

This makes it suitable for many factory electrical systems.

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6. Frame D Industrial Construction

The Frame D design provides additional power capacity while maintaining a relatively compact industrial package compared with much larger drive frames.

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7. Dynamic Braking Capability

The brake IGBT allows an external braking resistor to be incorporated when rapid or controlled deceleration is needed.

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8. Enhanced 24 V DC I/O

The enhanced I/O provides a practical interface with PLCs and other machine-control systems.

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9. Configured Product Architecture

The long catalog number allows the drive to be ordered with a defined combination of options.

This can simplify procurement and standardization.

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10. Suitable for Industrial Retrofit Work

For facilities already using PowerFlex 70 drives, the 21AD027 can fit naturally into an existing PowerFlex-oriented maintenance environment.

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20. Recommended Same-Series or Closely Related Models

The following five models are useful when comparing the 21AD027 with other PowerFlex 70 products.

Model / Catalog Number	Series	Input	Current	Normal Duty	Heavy Duty	Frame
21AD014A3AYNAEC0NNNN-ND-B0-C1-P1	PowerFlex 70 Configured	480 VAC, 3-phase	14 A	10 HP	7.5 HP	C
21AD022A3AYNAEC0NNNN-ND-B0-C1-P1	PowerFlex 70 Configured / Related	480 VAC, 3-phase	22 A	15 HP	10 HP	D
21AD027A3AYNAEC0NNNN-ND-B0-C1-P1	PowerFlex 70 Configured	480 VAC, 3-phase	27 A	20 HP	15 HP	D
21AD034A3AYNAEC0NNNN-ND-B0-C1-P1	PowerFlex 70 Configured / Related	480 VAC, 3-phase	34 A	25 HP	20 HP	D
21AD040A3AYNAEC0NNNN-ND-B0-C1-P1	PowerFlex 70 Configured / Related	480 VAC, 3-phase	40 A	30 HP	25 HP	D
21AD052A3AYNAEC0NNNN-ND-B0-C1-P1	PowerFlex 70 Configured / Related	480 VAC, 3-phase	52 A	40 HP	30 HP	E

For the standard PowerFlex 70 rating family, the 480 VAC models progress from 14 A / 10 HP through 22 A / 15 HP, 27 A / 20 HP, 34 A / 25 HP, 40 A / 30 HP and 52 A / 40 HP.

The exact long-form 21A catalog suffix should always be verified against the desired configuration before ordering.

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21. Same-Series Electrical Comparison

Model	Output Current	Normal Duty	Heavy Duty	Approx. Power, ND	Approx. Power, HD
21AD014A3AYNAEC0NNNN-ND-B0-C1-P1	14 A	10 HP	7.5 HP	7.5 kW	5.5 kW
21AD022A3AYNAEC0NNNN-ND-B0-C1-P1	22 A	15 HP	10 HP	11 kW	7.5 kW
21AD027A3AYNAEC0NNNN-ND-B0-C1-P1	27 A	20 HP	15 HP	15 kW	11 kW
21AD034A3AYNAEC0NNNN-ND-B0-C1-P1	34 A	25 HP	20 HP	18.5 kW	15 kW
21AD040A3AYNAEC0NNNN-ND-B0-C1-P1	40 A	30 HP	25 HP	22 kW	18.5 kW
21AD052A3AYNAEC0NNNN-ND-B0-C1-P1	52 A	40 HP	30 HP	30 kW	22 kW

The standard 480 VAC PowerFlex 70 technical data confirms the 20 HP / 15 HP rating for the 27 A model and the corresponding progression to the larger 34 A, 40 A and 52 A models.

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22. Same-Series Mechanical Comparison

Model	Frame	Approx. Height	Approx. Width	Approx. Depth	Approx. Weight
21AD014A3AYNAEC0NNNN-ND-B0-C1-P1	C	300 mm	180 mm	138 mm	6.89 kg
21AD022A3AYNAEC0NNNN-ND-B0-C1-P1	D	350 mm	220 mm	169 mm	9.25 kg
21AD027A3AYNAEC0NNNN-ND-B0-C1-P1	D	350 mm	220 mm	169 mm	9.25 kg
21AD034A3AYNAEC0NNNN-ND-B0-C1-P1	D	350 mm	220 mm	169 mm	9.25 kg
21AD040A3AYNAEC0NNNN-ND-B0-C1-P1	D	350 mm	220 mm	169 mm	9.25 kg
21AD052A3AYNAEC0NNNN-ND-B0-C1-P1	E	Larger Frame E package	Larger	Larger	Higher

The important point is that the 27 A, 34 A and 40 A models share the Frame D mechanical class, while the 14 A model is Frame C and the 52 A model moves into Frame E.

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23. Five Same-Brand Popular Related Models

The following models represent other commonly encountered PowerFlex products and are useful for comparison.

They should be considered related products rather than direct replacements.

Model / Catalog Number	Series	Input	Current / Power	Approx. Dimensions	Approx. Weight
25B-D010N114	PowerFlex 525	380–480 VAC, 3-phase	10.5 A / 5 HP class	Approx. 228 × 140 × 239 mm	2.193 kg
20AD027	PowerFlex 70	480 VAC, 3-phase	27 A / 20 HP ND	Approx. 350 × 220 × 169 mm	9.25 kg
20AD034	PowerFlex 70	480 VAC, 3-phase	34 A / 25 HP ND	Approx. 350 × 220 × 169 mm	9.25 kg
20F1ANE033JA0NNNNN	PowerFlex 753	480 VAC class	Configuration dependent	Configuration dependent	Configuration dependent
20G11FD052AA0NNNNN	PowerFlex 755	480 VAC class	Higher-power industrial class	Configuration dependent	Configuration dependent

The PowerFlex 525 is a substantially smaller drive platform, while the PowerFlex 753 and 755 families are intended for more advanced industrial drive applications.

The PowerFlex 70 models in the table are the closest family-level comparison for the 21AD027.

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24. PowerFlex 70 Versus PowerFlex 525

The PowerFlex 525 is a useful comparison because it occupies a compact industrial AC-drive category.

Feature	PowerFlex 70 27 A	PowerFlex 525
Model	21AD027A3AYNAEC0NNNN-ND-B0-C1-P1	25B-D010N114
Product Family	PowerFlex 70	PowerFlex 525
Input Voltage	480 VAC class	380–480 VAC
Input Phase	3-phase	3-phase
Output Current	27 A	10.5 A
Normal-Duty Power	20 HP	5 HP
Frame	D	B
Approx. Weight	9.25 kg	2.193 kg
Approx. Dimensions	350 × 220 × 169 mm	228.09 × 139.95 × 239.01 mm
Typical Position	Medium-power industrial drive	Compact machine drive
Communications	Configuration dependent	Embedded networking available
Safety	Configuration dependent	Advanced integrated safety functions

The PowerFlex 525 is much smaller and lighter than the 27 A PowerFlex 70 and belongs to a different product architecture.

For a new compact machine, a PowerFlex 525 may be considered where its power rating and functionality are sufficient.

For an existing PowerFlex 70 machine, the 21AD027 remains the closer platform match.

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25. PowerFlex 70 Versus PowerFlex 753

The PowerFlex 753 belongs to a more advanced industrial-drive platform.

Feature	PowerFlex 70	PowerFlex 753
Product Family	PowerFlex 70	PowerFlex 753
Main Role	General industrial variable-speed control	Advanced industrial AC drive
Application	Conventional machinery	More demanding machinery and process systems
Feedback	Configuration dependent	Broader feedback capability
Communications	Optional / configuration dependent	Extensive options
Control Complexity	General industrial	More advanced
Typical Use	Conveyors, pumps, fans, mixers	Complex machinery and process control
Replacement Relationship	Existing platform	Modernization option rather than drop-in replacement

The PowerFlex 753 should therefore be evaluated according to application requirements rather than simply comparing horsepower.

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26. PowerFlex 70 Versus PowerFlex 755

The PowerFlex 755 is another related high-level industrial AC-drive family.

Feature	PowerFlex 70	PowerFlex 755
Product Generation	Established industrial drive platform	Advanced industrial drive platform
Typical Application	General-purpose machinery	Higher-performance industrial systems
Feedback	Configuration dependent	Broad feedback options
Networking	Configuration dependent	Extensive communication options
Motion Capability	More limited	More advanced
System Integration	Conventional industrial control	Advanced automation
Typical Selection Reason	Existing PowerFlex 70 architecture	New or upgraded demanding systems

For a straightforward 20 HP variable-speed conveyor or pump, the PowerFlex 70 architecture can be entirely appropriate.

For complex motion, extensive networking, or demanding feedback requirements, a newer platform may be worth evaluating.

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27. Conveyor Application Example

Consider a conveyor driven by a 20 HP, 480 VAC three-phase motor.

The machine may require controlled acceleration, several operating speeds, and a controlled stopping sequence.

The 21AD027 provides the required current class for this type of application when the actual motor full-load current falls within the drive’s rating.

The acceleration ramp can be configured to prevent the conveyor from starting too aggressively.

This can help reduce mechanical shock to the belt, gearbox, chain, and coupling.

The speed reference can also be changed according to production requirements.

If the conveyor carries heavy material, the drive’s heavy-duty rating should be evaluated rather than selecting the drive solely from the motor horsepower.

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28. Pump Application Example

A 20 HP pump motor can operate at different speeds depending on the process.

The 21AD027 can vary the motor speed according to the required operating point.

This can be useful for:

• Industrial circulation
• Cooling systems
• Process water
• Fluid transfer
• Pressure-control systems

The pump manufacturer should be consulted regarding minimum speed, maximum speed, and motor cooling requirements.

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29. Fan and Blower Application Example

A large industrial fan may require a 15–20 HP motor.

The 21AD027 provides sufficient current capacity for many applications in this range.

The motor can run at reduced speed when full airflow is not required.

The drive can also provide a controlled startup, reducing the sudden mechanical impact that can occur when a large fan is connected directly to the line.

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30. Mixer Application Example

For a 20 HP mixer, the motor’s starting and running torque should be considered carefully.

The mechanical load can change significantly as the mixing material changes.

A machine that appears to be a 20 HP application may require a larger drive if the actual current demand or overload duty exceeds the normal-duty rating.

For this reason, the motor nameplate current and actual process cycle are more important than horsepower alone.

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31. Material-Handling Application

The 21AD027 is well suited to larger material-handling systems.

Examples include:

• Heavy conveyors
• Feed systems
• Rollers
• Transfer lines
• Sorting systems
• Production-line material movement

The ability to program acceleration and deceleration is especially useful where heavy mechanical equipment must be started and stopped repeatedly.

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32. High-Inertia Machinery

The 27 A drive class is suitable for some higher-inertia machines, provided the braking and overload requirements are properly evaluated.

A high-inertia load stores substantial mechanical energy.

When the motor decelerates, that energy can return to the drive.

The brake IGBT provides a useful means of connecting a suitable external dynamic-braking resistor.

For machines requiring very rapid stops, the braking resistor should be sized carefully based on actual mechanical calculations.

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33. Cabinet Installation

The approximate Frame D envelope is:

350 mm high × 220 mm wide × 169 mm deep

with an approximate drive weight of:

9.25 kg.

This is larger than the Frame C 14 A drive.

The cabinet should therefore be designed with adequate room around the drive.

Important installation considerations include:

• Power-cable entry
• Motor-cable exit
• Control wiring
• Grounding
• Ventilation
• Service access
• Braking components
• Upstream protection
• PLC and terminal blocks
• Communication equipment

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34. Thermal Management

Thermal design becomes increasingly important as drive power increases.

The 21AD027 is a 20 HP-class drive and therefore generates more heat than the smaller PowerFlex 70 models.

If several drives are installed in one cabinet, the total heat load needs to be considered.

Cabinet ventilation must prevent hot air from accumulating around the drive.

The ambient temperature, enclosure size, fan arrangement, and other heat-producing equipment all influence the final thermal design.

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35. Motor Selection

The motor should be checked against the drive’s electrical rating.

Motor Parameter	What to Check
Motor Voltage	Must match the drive/application
Full-Load Current	Must be compatible with drive current
Horsepower	Compare with ND/HD rating
Frequency	Confirm required operating frequency
Speed	Check required speed range
Service Factor	Consider in application evaluation
Duty Cycle	Check acceleration and overload requirements
Insulation	Suitable for inverter operation
Cooling	Adequate at reduced speed
Feedback	Determine whether encoder is required

A 20 HP motor is not automatically compatible simply because the drive is labeled 20 HP.

The motor nameplate current remains critical.

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36. Maintenance Considerations

Routine inspection should include the drive itself and the surrounding electrical system.

Recommended inspection areas include:

• Cooling passages
• Cabinet ventilation
• Electrical terminals
• Grounding connections
• Motor cables
• Control wiring
• Signs of overheating
• Dust accumulation
• Moisture contamination
• Unusual noise
• Fault history

A drive that repeatedly trips should not simply be reset without investigating the underlying cause.

Potential causes can include:

• Excessive motor current
• Mechanical overload
• Motor-cable problems
• Insufficient acceleration time
• Excessive deceleration demand
• DC-bus overvoltage
• Overtemperature
• Incoming power problems

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37. Retrofit Considerations

The complete catalog number should be recorded before replacing an existing drive.

The following should be compared:

Retrofit Check	Requirement
Original Model	Compare complete catalog number
Input Voltage	480 VAC class
Motor Current	Compatible with 27 A class
Motor Power	20 HP ND / 15 HP HD class
Frame	D
Feedback	Confirm existing feedback arrangement
Brake	Confirm braking requirements
Bypass	Verify existing system does not require bypass
Control Power	Confirm C1 arrangement
Input Protection	Confirm upstream protection
I/O	Compare existing control wiring
Cabinet	Check Frame D dimensions
Weight	Approximately 9.25 kg
Communications	Verify PLC/network architecture

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38. Why Frame D Matters

Frame D is a significant point in the PowerFlex 70 product range.

The smaller 11 A and 14 A models use Frame C.

The 22 A, 27 A, 34 A and 40 A models move into Frame D.

This means that moving from the 14 A class to the 27 A class does not simply increase electrical capacity.

It also changes the mechanical package.

Feature	Frame C	Frame D
Approx. Height	300 mm	350 mm
Approx. Width	180 mm	220 mm
Approx. Depth	138 mm	169 mm
Approx. Weight	6.89 kg	9.25 kg

This is important when planning a replacement or new cabinet.

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39. 21AD027 Compared With 21AD014

The difference between these two models is straightforward.

Characteristic	21AD014	21AD027
Model / Catalog Number	21AD014A3AYNAEC0NNNN-ND-B0-C1-P1	21AD027A3AYNAEC0NNNN-ND-B0-C1-P1
Output Current	14 A	27 A
Normal Duty	10 HP	20 HP
Heavy Duty	7.5 HP	15 HP
Frame	C	D
Approx. Height	300 mm	350 mm
Approx. Width	180 mm	220 mm
Approx. Depth	138 mm	169 mm
Approx. Weight	6.89 kg	9.25 kg

The 21AD027 therefore provides almost twice the continuous output-current capacity of the 21AD014, while also moving to the larger Frame D enclosure.

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40. 21AD027 Compared With 21AD034

The 27 A and 34 A models are physically close because both belong to Frame D.

Characteristic	21AD027	21AD034
Model / Catalog Number	21AD027A3AYNAEC0NNNN-ND-B0-C1-P1	21AD034A3AYNAEC0NNNN-ND-B0-C1-P1
Current	27 A	34 A
Normal Duty	20 HP	25 HP
Heavy Duty	15 HP	20 HP
Frame	D	D
Approx. Weight	9.25 kg	9.25 kg
Approx. Height	350 mm	350 mm
Approx. Width	220 mm	220 mm
Approx. Depth	169 mm	169 mm

The 34 A model provides additional electrical capacity without moving to the next mechanical frame.

This can be useful when the motor is close to or above the 27 A current class.

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41. Product Selection Checklist

Before selecting the 21AD027, verify:

Selection Item	Requirement
Input Voltage	480 VAC class
Input Phase	Three-phase
Output Current	Up to 27 A continuous class
Normal-Duty Motor	Up to approximately 20 HP
Heavy-Duty Motor	Up to approximately 15 HP
Frame	D
Enclosure	Suitable IP20/NEMA Type 1 installation
Braking	Evaluate external resistor requirement
Feedback	No encoder in specified configuration
Bypass	None
Control Power	Drive-only
Input Protection	Must be supplied appropriately
I/O	Enhanced 24 V DC
Cabinet Space	Minimum Frame D envelope
Weight	Approximately 9.25 kg
Motor Cable	Correctly sized and installed
Thermal Design	Adequate ventilation
Communications	Verify machine-control requirements

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42. Advantages for Machine Builders

The configured-drive architecture is particularly useful for machine builders.

The long catalog number identifies a specific collection of options.

This can help standardize machine designs.

For example, a machine builder may use the same configuration across several machine models while changing only the current rating.

This simplifies purchasing, documentation, and maintenance.

The PowerFlex 70 platform also provides a familiar architecture for facilities already using the same family.

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43. Advantages for Maintenance Departments

For industrial maintenance teams, standardization can be valuable.

If several machines use PowerFlex 70 drives, technicians can become familiar with:

• Drive parameters
• Fault handling
• Control wiring
• Motor setup
• Acceleration/deceleration settings
• Braking
• Troubleshooting procedures

This can make maintenance work more consistent.

The complete catalog number should still be recorded because two drives from the same family can have substantially different options.

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44. Advantages for Retrofit Projects

The 21AD027 can be useful in retrofit projects involving motors in the 15–20 HP range.

The Frame D size provides substantially more current capacity than the 14 A Frame C drive.

At the same time, it avoids moving immediately into the larger Frame E class.

This makes it a useful middle-range PowerFlex 70 model.

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45. Practical Conveyor Example

Imagine a production conveyor driven by a 20 HP motor.

The conveyor must start several times per hour and must reach a normal production speed smoothly.

The 21AD027 can regulate motor frequency during startup.

Instead of applying the full motor speed immediately, the drive can increase frequency according to a programmed acceleration ramp.

During production, the speed reference can be changed.

During stopping, the drive can decelerate the motor according to the selected deceleration profile.

If the conveyor has significant stored energy, the brake IGBT and external braking resistor can be evaluated.

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46. Practical Pump Example

A 15 HP pump motor may operate at several different process conditions.

The drive can vary motor speed according to the process command.

At low process demand, the motor can run below full speed.

At higher demand, the motor can increase speed.

This makes the drive suitable for many industrial process systems where fixed-speed operation is not ideal.

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47. Practical Fan Example

A 20 HP industrial ventilation fan may require different airflow levels throughout a production cycle.

The drive can regulate the motor speed to provide the required airflow.

Controlled acceleration also reduces the mechanical shock associated with starting a large fan.

The motor’s cooling characteristics should be considered when operating continuously at reduced speed.

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48. Practical Mixer Example

For a 15 HP heavy-duty mixer application, the heavy-duty rating of the drive may be more relevant than the 20 HP normal-duty rating.

The machine may experience high torque during startup.

The drive should therefore be selected based on actual current and torque requirements.

The process load should be measured or calculated whenever possible.

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49. Same-Brand Popular Model Comparison

Model / Catalog Number	Series	Typical Role	Current / Power	Approx. Dimensions	Approx. Weight
21AD027A3AYNAEC0NNNN-ND-B0-C1-P1	PowerFlex 70 Configured	Medium-power industrial drive	27 A / 20 HP ND	350 × 220 × 169 mm	9.25 kg
25B-D010N114	PowerFlex 525	Compact machine drive	10.5 A / 5 HP class	228.09 × 139.95 × 239.01 mm	2.193 kg
20AD034	PowerFlex 70	Larger general-purpose drive	34 A / 25 HP ND	350 × 220 × 169 mm	9.25 kg
20F1ANE033JA0NNNNN	PowerFlex 753	Advanced industrial drive	Configuration dependent	Configuration dependent	Configuration dependent
20G11FD052AA0NNNNN	PowerFlex 755	Advanced/high-power industrial drive	Configuration dependent	Configuration dependent	Configuration dependent

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50. Complete Product Parameter Summary

Parameter	Final Specification
Brand	Allen-Bradley
Product Family	PowerFlex
Series	PowerFlex 70
Product Type	Configured Adjustable Frequency AC Drive
Model / Catalog Number	21AD027A3AYNAEC0NNNN-ND-B0-C1-P1
Input Voltage	480 VAC
Input Phase	3 Phase
Output Current	27 A
1-Minute Current	Approximately 33 A
3-Second Current	Approximately 44 A
Normal-Duty Rating	20 HP
Normal-Duty Power	Approximately 15 kW
Heavy-Duty Rating	15 HP
Heavy-Duty Power	Approximately 11 kW
Frame	D
Enclosure	IP20 / NEMA/UL Type 1
Brake IGBT	Yes
Internal Brake Resistor	No
Feedback	No encoder feedback
I/O	Enhanced 24 V DC
Bypass	No
Control Power	Drive-only
Input Protection	P1 – no integrated input protection
Approx. Height	350 mm
Approx. Width	220 mm
Approx. Depth	169 mm
Approx. Dimensions	350 × 220 × 169 mm
Approx. Weight	9.25 kg
Approx. Weight in Pounds	20.4 lb
Mounting	Panel / cabinet
Cooling	Integral forced-air cooling
Typical Motor	15–20 HP class
Typical Applications	Conveyors, pumps, fans, blowers, mixers, packaging and process machinery

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51. Same-Series Recommendation Table

Model / Catalog Number	Current	Normal Duty	Heavy Duty	Frame	Approx. Dimensions	Approx. Weight
21AD014A3AYNAEC0NNNN-ND-B0-C1-P1	14 A	10 HP	7.5 HP	C	300 × 180 × 138 mm	6.89 kg
21AD022A3AYNAEC0NNNN-ND-B0-C1-P1	22 A	15 HP	10 HP	D	350 × 220 × 169 mm	9.25 kg
21AD027A3AYNAEC0NNNN-ND-B0-C1-P1	27 A	20 HP	15 HP	D	350 × 220 × 169 mm	9.25 kg
21AD034A3AYNAEC0NNNN-ND-B0-C1-P1	34 A	25 HP	20 HP	D	350 × 220 × 169 mm	9.25 kg
21AD040A3AYNAEC0NNNN-ND-B0-C1-P1	40 A	30 HP	25 HP	D	350 × 220 × 169 mm	9.25 kg
21AD052A3AYNAEC0NNNN-ND-B0-C1-P1	52 A	40 HP	30 HP	E	Larger Frame E	Higher

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52. Five Same-Brand Related Models

Model / Catalog Number	Product Series	Input	Current / Power	Dimensions	Weight
25B-D010N114	PowerFlex 525	380–480 VAC, 3-phase	10.5 A / 5 HP class	228.09 × 139.95 × 239.01 mm	2.193 kg
20AD027	PowerFlex 70	480 VAC, 3-phase	27 A / 20 HP ND	350 × 220 × 169 mm	9.25 kg
20AD034	PowerFlex 70	480 VAC, 3-phase	34 A / 25 HP ND	350 × 220 × 169 mm	9.25 kg
20F1ANE033JA0NNNNN	PowerFlex 753	480 VAC class	Configuration dependent	Configuration dependent	Configuration dependent
20G11FD052AA0NNNNN	PowerFlex 755	480 VAC class	Configuration dependent	Configuration dependent	Configuration dependent

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53. Product Selection by Application

Application	21AD027 Suitability	Main Consideration
Conveyor	Excellent for appropriate 15–20 HP applications	Check starting torque and inertia
Pump	Suitable	Check pump speed range
Fan	Suitable	Check motor cooling at reduced speed
Blower	Suitable	Check starting load
Mixer	Suitable with proper sizing	Check heavy-duty torque
Packaging	Suitable	Check acceleration/deceleration cycle
Material Handling	Suitable	Check braking requirements
Process Machinery	Suitable	Check continuous load
High-Inertia Machine	Suitable with braking analysis	External braking resistor may be needed
Precision Positioning	Application dependent	Consider feedback/motion platform
Outdoor Installation	Requires enclosure	Bare IP20 drive is not weatherproof
Washdown Area	Requires additional protection	Use suitable enclosure

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54. Final Product Description

The Allen-Bradley 21AD027A3AYNAEC0NNNN-ND-B0-C1-P1 is a PowerFlex 70 configured 480 VAC three-phase adjustable-frequency AC drive with a 27 A continuous output-current rating.

Its normal-duty rating is approximately 20 HP / 15 kW, while the heavy-duty rating is approximately 15 HP / 11 kW. The corresponding PowerFlex 70 27 A model is a Frame D drive.

The approximate physical dimensions are 350 × 220 × 169 mm, and the approximate drive weight is 9.25 kg.

The drive configuration includes a brake IGBT, enhanced 24 V DC I/O, no encoder feedback, no bypass, drive-only control power, and no integrated input protection under the P1 configuration.

Its 27 A continuous output makes it suitable for a wide range of medium-power industrial machinery.

Typical applications include heavy conveyors, pumps, fans, blowers, mixers, packaging machinery, material-handling equipment, rollers, feeders, and process machinery.

The Frame D construction is an important characteristic because it provides considerably more current capacity than the smaller Frame C 14 A PowerFlex 70 models while maintaining a manageable industrial cabinet footprint.

The drive’s braking capability is also useful for machines that have substantial rotating inertia or require controlled deceleration.

For installation and replacement work, the complete catalog number should be checked rather than matching only the 27 A rating. The suffixes define important configuration details.

The motor nameplate should also be checked carefully.

The most important electrical selection points are motor voltage, full-load current, horsepower, duty cycle, overload requirements, acceleration, deceleration, braking requirements, ambient temperature, and cabinet cooling.

For a conventional 20 HP normal-duty, 480 VAC, three-phase industrial motor, the 21AD027 represents a substantial PowerFlex 70 drive configuration with a useful combination of current capacity, industrial I/O, dynamic-braking capability, and cabinet-mount construction.