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Allen-Bradley MPL-B320P-HK74AA Servo Motor

1. Product Introduction

The Allen-Bradley MPL-B320P-HK74AA is a low-inertia brushless AC servo motor designed for high-speed industrial motion control. It belongs to the MP-Series MPL servo motor family and is configured for 460 V-class operation, a 100 mm frame size, a 50.8 mm magnetic stack, 5000 RPM operation, incremental encoder feedback, a keyless shaft, and an integral 24 V DC holding brake.

This model is intended for applications where rapid acceleration, repeatable positioning, controlled deceleration, and compact mechanical integration are important. Its low-inertia rotor design allows the motor to respond quickly to command changes, making it suitable for machine axes that repeatedly accelerate, stop, reverse, index, and reposition.

The MPL-B320P-HK74AA uses a 2000-line incremental encoder for feedback. The encoder supplies the motion controller with position and speed information so that the servo system can maintain closed-loop control during operation. The keyless shaft configuration is particularly useful where the mechanical transmission is designed around a shaft clamp, hub, or other keyless coupling arrangement.

A major feature of this particular configuration is the integral 24 V DC brake. The brake is primarily intended as a holding device when the servo is disabled or when the machine requires the shaft to remain stationary under load. It should not normally be treated as the primary dynamic stopping mechanism for repeated high-energy braking operations.

The motor uses a right-angle SpeedTEC DIN connector that can be rotated through 180 degrees. This provides additional flexibility when routing motor cables inside compact machine structures and can help reduce interference between the motor connector, cable assembly, machine guarding, and adjacent components.

The model is associated with the MPL low-inertia brushless servo motor family. The model configuration identifies the voltage class, frame size, stack length, speed class, feedback type, shaft arrangement, connector arrangement, and brake option.

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2. Basic Product Parameters

Parameter	Specification
Model	MPL-B320P-HK74AA
Brand	Allen-Bradley
Product Family	MP-Series MPL
Product Type	Low-inertia brushless AC rotary servo motor
Motor Type	AC permanent-magnet servo motor
Voltage Class	460 V AC class
Armature Voltage	460 V
Frame Size	100 mm / Frame 3
Magnetic Stack Length	50.8 mm / 2.0 in
Rated Speed	5000 RPM
Maximum Speed	5000 RPM
Continuous Output Torque	Approximately 3.05 N·m
Peak Output Torque	Approximately 7.91 N·m
Continuous Rated Power	Approximately 1.5 kW
Feedback	2000-line incremental encoder
Shaft	Keyless shaft extension
Brake	Integral 24 V DC brake
Connector	SpeedTEC DIN, right-angle, 180° rotatable
Mounting	IEC metric flange mounting
Mounting Holes	Free mounting holes, Type FF
Shaft Seal	No shaft seal
Rotor Inertia	Approximately 0.000078 kg·m²
Approximate Motor Weight	Approximately 4.5 kg, depending on exact configuration and production revision
Frame Dimension	100 mm nominal frame size
Magnetic Stack Dimension	50.8 mm
Overall Envelope	Configuration-dependent; use the applicable mechanical drawing for exact installation dimensions
Intended Duty	Closed-loop servo motion control
Typical Drive Family	Compatible with MP-Series/Kinetix servo drive systems according to system configuration

The principal electrical and mechanical characteristics of the MPL-B320P family are 5000 RPM operation, approximately 3.05 N·m continuous torque, approximately 7.91 N·m peak torque, and 1.5 kW continuous power.

The 100 mm frame and 50.8 mm magnetic stack are especially important when replacing an existing motor because these dimensions establish the basic mechanical envelope and mounting class.

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3. Brand

Brand: Allen-Bradley

Allen-Bradley is the brand associated with this servo motor family.

For catalog and engineering purposes, the MPL-B320P-HK74AA is identified as an MP-Series MPL 480 V AC rotary servo motor.

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4. Product Series

Series: MP-Series MPL Low-Inertia Brushless Servo Motors

The MPL series is a family of compact, high-speed, brushless servo motors intended for industrial motion applications.

The low-inertia construction is one of the most important characteristics of the series. A lower rotor inertia allows the motor to change speed rapidly when the controller changes the commanded position or velocity.

The MPL family includes several frame sizes, stack lengths, speed ratings, feedback technologies, shaft configurations, and brake configurations. The MPL-B320P-HK74AA represents one particular combination of these options.

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5. Understanding the Model Number

The model number can be read as a configuration code:

MPL-B320P-HK74AA

Code	Meaning
MPL	MPL low-inertia brushless servo motor family
B	460 V-class motor configuration
3	Frame 3 / approximately 100 mm frame
20	20-series magnetic stack / 50.8 mm stack
P	5000 RPM speed class
H	2000-line incremental encoder feedback
K	Keyless shaft
7	SpeedTEC DIN right-angle connector, 180° rotatable
4	Integral 24 V DC brake
AA	Standard catalog configuration designation

The most important distinction between this model and the similar MPL-B320P-HK72AA is the brake configuration. The HK72AA version does not have the integral brake, while the HK74AA version includes the 24 V DC brake.

The feedback and shaft configuration remain important as well. The “H” configuration identifies incremental encoder feedback, while “K” identifies the keyless shaft arrangement.

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6. Detailed Technical Specifications

Technical Parameter	MPL-B320P-HK74AA Specification
Model	MPL-B320P-HK74AA
Servo Motor Class	Low-inertia AC servo
Rated Voltage Class	460 V AC
Armature Voltage	460 V
Rated Speed	5000 RPM
Maximum Speed	5000 RPM
Continuous Torque	3.05 N·m
Peak Torque	7.91 N·m
Rated Continuous Power	1.5 kW
Frame Size	100 mm
Frame Designation	Frame 3
Stack Length	50.8 mm
Stack Designation	20
Feedback	2000-line incremental encoder
Shaft Design	Keyless
Brake	24 V DC integral brake
Connector	SpeedTEC DIN
Connector Orientation	Right angle
Connector Rotation	180° rotatable
Mounting	IEC metric flange
Shaft Seal	None
Rotor Inertia	Approx. 7.8 × 10⁻⁵ kg·m²
Approx. Weight	Approx. 4.5 kg
Frame Dimension	100 mm nominal
Stack Dimension	50.8 mm
Overall Dimensions	Must be confirmed from the mechanical drawing for the exact revision
Feedback Type	Incremental
Application Class	Industrial servo motion
Construction	Brushless permanent-magnet motor

The 5000 RPM speed rating is one of the defining characteristics of the B320P motor family. The motor is therefore intended for applications where relatively high rotational speed is combined with accurate closed-loop positioning.

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7. Motor Power and Torque

The MPL-B320P motor class provides approximately 3.05 N·m of continuous output torque and approximately 7.91 N·m of peak torque, with approximately 1.5 kW continuous rated power.

The difference between continuous torque and peak torque is important in servo applications.

Continuous torque represents the torque that the motor can provide under the applicable continuous operating conditions. Peak torque represents the higher short-duration torque capability available for acceleration, deceleration, rapid positioning, or temporary load disturbances.

In a typical servo application, the motor does not operate continuously at peak torque. Instead, the controller uses higher torque for short periods and returns toward the continuous operating range once the machine reaches its commanded speed or position.

This characteristic makes the motor appropriate for machinery that has frequent acceleration and deceleration cycles rather than applications that require a constant high torque at low speed.

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8. 5000 RPM High-Speed Operation

The MPL-B320P-HK74AA is rated for 5000 RPM.

High-speed operation is useful in machinery where the mechanical process requires fast rotary movement, short cycle times, or high linear speed through a belt, screw, roller, or other transmission mechanism.

When a servo motor is connected to a gearbox, belt drive, ball screw, timing belt, or direct-drive mechanism, the actual machine-axis speed depends on the transmission ratio.

For example, a 5000 RPM motor connected to a reduction gearbox does not mean that the output shaft must rotate at 5000 RPM. The transmission can trade speed for torque according to the machine design.

This makes the motor flexible enough for many different machine architectures.

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9. 2000-Line Incremental Encoder

The H portion of the model number identifies the incremental encoder configuration.

The MPL-B320P-HK74AA uses a 2000-line incremental encoder.

The encoder provides feedback regarding motor shaft movement to the servo control system.

This feedback is essential because the controller needs to compare commanded motion with actual motor movement.

If the controller commands the motor to rotate to a particular position, the feedback system provides information that allows the servo system to detect actual movement and correct the motor current accordingly.

Incremental encoder feedback is widely used in industrial servo systems because it provides high-speed feedback suitable for closed-loop velocity and position control.

When replacing this motor, the feedback type should always be checked carefully. A motor with the same frame and torque rating but a different feedback technology is not automatically a direct electrical replacement.

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10. Keyless Shaft Configuration

The K in MPL-B320P-HK74AA identifies the keyless shaft configuration.

A keyless shaft is designed for mechanical coupling arrangements that do not rely on a traditional shaft key.

This can be useful in applications using clamping hubs, precision couplings, or other mechanical connection systems specifically designed for keyless servo shafts.

The absence of a shaft key also means that the replacement motor must be mechanically compatible with the existing coupling.

When replacing an older motor, the shaft diameter, shaft length, coupling type, available clearance, mounting pattern, and shaft interface should all be checked before installation.

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11. Integral 24 V DC Brake

The 4 in the model number indicates the integral brake option.

The MPL-B320P-HK74AA has a 24 V DC holding brake.

The brake is particularly useful for vertical axes and other applications where the load needs to remain stationary when motor torque is removed.

Typical examples include vertical lifting mechanisms, Z-axis machinery, positioning systems, and equipment where gravity could cause the axis to move when the servo is disabled.

The brake should be treated primarily as a holding device rather than as the normal means of repeatedly stopping a moving load.

For dynamic stopping, the servo drive normally controls motor torque and deceleration. The brake is then used to hold the axis after the motor has stopped or when the control sequence requires mechanical holding.

The 24 V DC brake also means that the machine’s control architecture must provide the appropriate brake supply and control sequence.

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12. SpeedTEC DIN Connector

The motor uses a SpeedTEC DIN right-angle connector with 180° rotation capability.

This connector arrangement provides considerable flexibility in machine design.

The right-angle configuration helps reduce the amount of space required behind or beside the motor.

The ability to rotate the connector through 180 degrees allows the cable exit direction to be selected according to the machine’s available cable routing space.

This is particularly useful in compact equipment where the motor is installed close to guarding, linear guides, gearboxes, machine frames, or other moving components.

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13. Dimensions

The most clearly defined dimensional information for this model is its 100 mm frame size and 50.8 mm magnetic stack length.

Dimension Parameter	Value
Model	MPL-B320P-HK74AA
Frame Size	100 mm
Frame Designation	3
Magnetic Stack Length	50.8 mm
Stack Designation	20
Nominal Frame Width Class	100 mm
Mounting Type	IEC metric flange
Shaft Configuration	Keyless
Connector	Right-angle DIN
Connector Rotation	180°
Overall Motor Length	Verify mechanical drawing
Overall Motor Diameter	Verify mechanical drawing
Shaft Projection	Verify mechanical drawing
Mounting Bolt Circle	Verify mechanical drawing
Mounting Hole Dimensions	Verify mechanical drawing
Approximate Weight	4.5 kg

The reason for specifying the overall envelope as “verify mechanical drawing” rather than giving an assumed measurement is that the connector, brake housing, shaft configuration, and exact production revision can affect the final mechanical envelope.

For engineering replacement work, the 100 mm frame and 50.8 mm stack should be treated as the primary catalog dimensions, while the exact shaft projection and overall motor length should be checked against the actual installation drawing.

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14. Weight

A useful reference value for the B320P motor class is approximately 4.5 kg.

Weight Parameter	Value
Model	MPL-B320P-HK74AA
Approximate Motor Weight	4.5 kg
Weight Unit	kg
Weight Classification	Approximate catalog/family reference
Exact Shipping Weight	May differ
Exact Installed Weight	Verify against the specific unit and revision

The actual delivered weight can differ because packaging, cable accessories, connector hardware, mounting accessories, and production revisions can change the shipping weight.

For machine design calculations, the motor’s actual mass should be confirmed from the physical unit or the mechanical documentation associated with the exact revision.

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15. Operating Characteristics

The low-inertia design is intended to provide fast dynamic response.

A low-inertia servo motor can accelerate and decelerate its rotor more quickly than a motor with substantially higher rotor inertia when the available torque and control conditions are comparable.

This is valuable in indexing machinery, packaging equipment, pick-and-place systems, cutting machines, assembly equipment, and other machines where the axis repeatedly changes velocity.

The motor’s approximately 7.8 × 10⁻⁵ kg·m² rotor inertia is relatively low for its power class. The exact machine response, however, depends not only on rotor inertia but also on reflected load inertia, gearbox ratio, coupling characteristics, servo tuning, friction, and load dynamics.

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16. Applications

Packaging Machinery

The MPL-B320P-HK74AA is suitable for packaging machinery requiring repeated indexing and high-speed motion.

Examples include film feeding, conveyor indexing, sealing mechanisms, product positioning, cutting, labeling, and synchronization between multiple machine axes.

The 5000 RPM rating provides sufficient speed for many high-cycle packaging mechanisms, while the incremental encoder supports closed-loop positioning.

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Material Handling

The motor can be used in automated material-handling equipment where accurate movement and repeatability are required.

Typical applications include conveyor positioning, transfer mechanisms, indexing tables, belt-driven axes, and automated sorting equipment.

The integral brake is particularly useful when an axis must remain stationary after the servo drive removes motor torque.

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CNC and Machine Tools

Servo motors are widely used in CNC and precision machinery for controlled rotary or linear movement.

The MPL-B320P-HK74AA can be used with suitable drive and mechanical transmission arrangements for axis positioning, tool movement, indexing, or auxiliary machine functions.

The exact suitability depends on required torque, speed, inertia ratio, feedback requirements, and drive compatibility.

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Robotics and Pick-and-Place Equipment

High-speed servo motors are frequently used for robotic positioning and pick-and-place mechanisms.

The relatively low rotor inertia of the MPL series allows fast changes in rotational speed.

In applications where the mechanical axis is vertically oriented, the integral brake can also be useful for holding the axis when the motor is disabled.

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Assembly Machinery

Automated assembly equipment often requires precise movement over repeated production cycles.

The MPL-B320P-HK74AA can be used in indexing mechanisms, rotary tables, actuator systems, screw-driving machinery, component positioning equipment, and automated assembly stations.

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Printing and Converting Equipment

Printing and converting machinery often requires coordinated speed and position control.

Servo motors can be used for web handling, roller synchronization, cutting, feeding, registration, and tension-related motion.

The encoder feedback and high-speed operating capability make the motor appropriate for applications requiring controlled rotary motion.

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Textile Machinery

Textile equipment can require rapid and repetitive motion with accurate synchronization between multiple axes.

The motor can be considered for feeding, winding, positioning, cutting, and other servo-controlled machine functions where the load requirements remain within the motor’s torque and speed capabilities.

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17. Main Product Advantages

17.1 High-Speed Operation

The 5000 RPM rating allows the motor to support high-speed machine cycles.

This is useful when machine productivity depends on rapid movement or when a relatively high motor speed is advantageous for the selected mechanical transmission.

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17.2 Low-Inertia Rotor

The low-inertia construction helps the motor respond quickly to changes in commanded speed.

This can be especially beneficial in machines that repeatedly accelerate, decelerate, reverse, and reposition.

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17.3 Integrated Holding Brake

The 24 V DC brake provides a mechanical holding function without requiring a separate external motor brake.

This is particularly useful for vertical axes and other applications where the load must remain stationary after servo torque is removed.

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17.4 Keyless Shaft

The keyless shaft configuration can simplify certain coupling arrangements.

It is especially suitable for machinery designed around clamping-type couplings or hubs.

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17.5 Flexible Connector Orientation

The right-angle SpeedTEC DIN connector can be rotated through 180 degrees.

This makes cable routing easier in compact machine installations.

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17.6 Closed-Loop Feedback

The 2000-line incremental encoder provides feedback for closed-loop servo operation.

The controller can continuously use feedback information to regulate position and velocity.

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17.7 Compact 100 mm Frame

The 100 mm frame size provides a practical balance between motor output and physical size.

It can fit applications where a larger motor would create mechanical interference or require additional machine space.

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17.8 1.5 kW Power Class

The approximately 1.5 kW continuous power rating places the motor in a useful range for many medium-duty servo axes.

The actual machine load should always be evaluated using continuous torque, peak torque, RMS torque, speed, inertia, duty cycle, and thermal conditions rather than power alone.

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18. Important Selection Considerations

When selecting the MPL-B320P-HK74AA for a machine, the following parameters should be evaluated:

Selection Parameter	MPL-B320P-HK74AA
Model	MPL-B320P-HK74AA
Voltage	460 V class
Speed	5000 RPM
Continuous Torque	3.05 N·m
Peak Torque	7.91 N·m
Power	1.5 kW
Frame	100 mm
Stack	50.8 mm
Feedback	2000-line incremental encoder
Shaft	Keyless
Brake	24 V DC
Rotor Inertia	Approx. 0.000078 kg·m²
Weight	Approx. 4.5 kg
Mounting	IEC metric
Connector	SpeedTEC DIN, right angle
Connector Adjustment	180°
Overall Dimensions	Confirm exact mechanical drawing
Application	Servo motion control

The most important point is that the motor should be selected based on the complete motion profile rather than simply matching the horsepower or RPM.

A servo axis should be evaluated according to acceleration time, deceleration time, load inertia, reflected inertia, duty cycle, continuous torque, peak torque, operating speed, and thermal requirements.

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19. Five Related Models in the Same Series

The following models are closely related to the MPL-B320P-HK74AA. They share the same general B320P motor platform while changing feedback, shaft, or brake configuration.

Related Model	Voltage	Frame	Stack	Speed	Feedback	Shaft	Brake	Approx. Power	Approx. Weight
MPL-B320P-HJ72AA	460 V	100 mm	50.8 mm	5000 RPM	2000-line incremental	Keyed	No	1.5 kW	Verify exact unit
MPL-B320P-HJ74AA	460 V	100 mm	50.8 mm	5000 RPM	2000-line incremental	Keyed	24 V DC	1.5 kW	Verify exact unit
MPL-B320P-HK72AA	460 V	100 mm	50.8 mm	5000 RPM	2000-line incremental	Keyless	No	1.5 kW	Verify exact unit
MPL-B320P-SK72AA	460 V	100 mm	50.8 mm	5000 RPM	Single-turn high-resolution	Keyless	No	1.5 kW	Verify exact unit
MPL-B320P-SK74AA	460 V	100 mm	50.8 mm	5000 RPM	Single-turn high-resolution	Keyless	24 V DC	1.5 kW	Verify exact unit

The B320P platform covers several feedback and mechanical configurations. The HJ and HK variants use incremental feedback, while the S-series variants use single-turn high-resolution feedback. The J designation indicates a keyed shaft and K indicates a keyless shaft. The 72 configuration is the no-brake version, while the 74 configuration includes the 24 V DC brake.

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20. Same-Series Model Comparison

Model	Feedback	Shaft	Brake	Speed	Frame	Stack	Continuous Torque	Power
MPL-B320P-HJ72AA	2000-line incremental	Keyed	No	5000 RPM	100 mm	50.8 mm	3.05 N·m	1.5 kW
MPL-B320P-HJ74AA	2000-line incremental	Keyed	24 V DC	5000 RPM	100 mm	50.8 mm	3.05 N·m	1.5 kW
MPL-B320P-HK72AA	2000-line incremental	Keyless	No	5000 RPM	100 mm	50.8 mm	3.05 N·m	1.5 kW
MPL-B320P-HK74AA	2000-line incremental	Keyless	24 V DC	5000 RPM	100 mm	50.8 mm	3.05 N·m	1.5 kW
MPL-B320P-SK72AA	Single-turn high-resolution	Keyless	No	5000 RPM	100 mm	50.8 mm	Approx. 3.05 N·m	1.5 kW
MPL-B320P-SK74AA	Single-turn high-resolution	Keyless	24 V DC	5000 RPM	100 mm	50.8 mm	Approx. 3.05 N·m	1.5 kW

The most direct mechanical alternative to the HK74AA is the HK72AA, because it retains the keyless shaft and incremental encoder arrangement but removes the integral brake.

The HJ74AA is another closely related configuration, retaining the brake and incremental encoder while changing the shaft from keyless to keyed.

The SK74AA is more different electrically because it changes the feedback technology to a single-turn high-resolution encoder while retaining the keyless shaft and brake configuration.

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21. Five Common Allen-Bradley Models

The following models are useful reference points within the same broader servo motor family. They represent different motor sizes or configurations and should not be treated as automatic drop-in replacements for the MPL-B320P-HK74AA.

Model	Series	Frame	Stack	Speed	Feedback / Configuration	Shaft	Brake	Approx. Continuous Torque	Approx. Power
MPL-B310P-HK72AA	MPL Low-Inertia	100 mm	25.4 mm	5000 RPM	2000-line incremental	Keyless	No	1.58 N·m	0.77 kW
MPL-B320P-MJ72AA	MPL Low-Inertia	100 mm	50.8 mm	5000 RPM	Multi-turn high-resolution	Keyed	No	3.05 N·m	1.5 kW
MPL-B320P-MK74AA	MPL Low-Inertia	100 mm	50.8 mm	5000 RPM	Multi-turn high-resolution	Keyless	24 V DC	3.05 N·m	1.5 kW
MPL-B330P-HK74AA	MPL Low-Inertia	100 mm	76.2 mm	5000 RPM	2000-line incremental	Keyless	24 V DC	4.18 N·m	1.8 kW
MPL-B420P-MK74AA	MPL Low-Inertia	115 mm class	50.8 mm	5000 RPM	Multi-turn high-resolution	Keyless	24 V DC	4.74 N·m	1.9 kW

The B320P, B330P, and B420P models illustrate how the same general servo family extends into different torque and mechanical classes. Published technical data places the B320P around 3.05 N·m continuous torque and 1.5 kW, the B330P around 4.18 N·m and 1.8 kW, and the B420P around 4.74 N·m and 1.9 kW.

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22. Practical Difference Between the Main B320P Configurations

Model	Keyless Shaft	Encoder	Brake	Main Difference
MPL-B320P-HK72AA	Yes	2000-line incremental	No	Basic keyless incremental configuration
MPL-B320P-HK74AA	Yes	2000-line incremental	24 V DC	Keyless incremental configuration with brake
MPL-B320P-HJ72AA	No	2000-line incremental	No	Keyed-shaft version without brake
MPL-B320P-HJ74AA	No	2000-line incremental	24 V DC	Keyed-shaft version with brake
MPL-B320P-SK72AA	Yes	Single-turn high-resolution	No	High-resolution feedback, no brake
MPL-B320P-SK74AA	Yes	Single-turn high-resolution	24 V DC	High-resolution feedback with brake

For an existing machine using a keyless shaft and brake, the HK74AA configuration is the closest match among these options.

If the existing machine does not require a holding brake, the HK72AA may represent the corresponding no-brake configuration.

If the mechanical transmission uses a keyed coupling, the HJ-series versions should be considered instead.

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23. Installation Considerations

The motor should be mounted on a suitable rigid machine structure capable of maintaining shaft alignment.

Misalignment between the servo shaft and the driven machine can increase bearing loading, coupling stress, vibration, and mechanical noise.

The coupling should be selected according to the motor shaft specifications and the driven load.

Because the shaft is keyless, the mechanical coupling must specifically support the keyless shaft arrangement.

Cable routing should also be planned carefully.

The 180° rotatable right-angle connector gives additional installation flexibility, but the cable should still be routed so that it is not exposed to excessive bending, pulling, crushing, abrasion, or repeated mechanical interference.

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24. Brake Installation Considerations

The 24 V DC brake should be controlled according to the servo system’s intended operating sequence.

For a vertical axis, the normal sequence generally requires the servo to establish sufficient motor torque before the holding brake is released.

When stopping, the servo system normally decelerates the load first and then applies the brake after the motor has reached an appropriate stopped condition.

The exact brake control sequence depends on the drive, machine safety architecture, load characteristics, and application requirements.

The brake should not be selected as a substitute for a properly engineered safety stopping system.

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25. Servo Tuning Considerations

Because this is a low-inertia servo motor, tuning should take the motor and load inertia relationship into account.

A servo system does not respond only according to the motor’s rated power.

The combined system includes:

• Motor rotor inertia.
• Coupling inertia.
• Gearbox inertia.
• Reflected load inertia.
• Mechanical compliance.
• Friction.
• Backlash.
• Load torque.
• Acceleration requirements.
• Deceleration requirements.

A machine with a very high reflected load inertia may behave very differently from a lightly loaded machine even when both use the same motor.

The control system should therefore be tuned for the actual machine rather than copied directly from another application.

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26. Maintenance

The MPL-B320P-HK74AA is a brushless servo motor and therefore does not use traditional mechanical brushes that require routine replacement.

Routine maintenance should instead focus on the mechanical and electrical installation.

Important inspection points include:

Inspection Item	Recommended Check
Model	MPL-B320P-HK74AA
Mounting	Check mounting bolts and machine structure
Shaft	Check coupling condition and alignment
Bearing	Check abnormal noise, vibration, or temperature
Encoder	Check feedback stability and connector condition
Brake	Check brake release and holding function
Connector	Inspect connector seating and cable condition
Cable	Check for bending, abrasion, and mechanical damage
Grounding	Check electrical grounding
Cooling	Ensure adequate heat dissipation
Vibration	Monitor abnormal vibration
Noise	Investigate unusual mechanical or electrical noise
Insulation	Test according to applicable maintenance procedures

Preventive maintenance is especially important in high-cycle machinery because a servo motor may perform thousands or millions of motion cycles over its service life.

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27. Replacement Considerations

When replacing an existing servo motor with an MPL-B320P-HK74AA, matching the model number alone is not enough.

The following items should be checked:

1. Motor voltage class.
2. Motor frame size.
3. Magnetic stack length.
4. Continuous torque.
5. Peak torque.
6. Rated speed.
7. Feedback technology.
8. Encoder resolution.
9. Shaft type.
10. Shaft dimensions.
11. Brake availability.
12. Brake voltage.
13. Connector type.
14. Connector orientation.
15. Mounting flange.
16. Mounting-hole arrangement.
17. Overall motor length.
18. Cable compatibility.
19. Servo-drive compatibility.
20. Machine control configuration.

The manufacturer has listed the MPL-B320P-HK74AA as discontinued, with MPL-B320P-SK74AA identified as an engineering replacement. Therefore, for a replacement project, the electrical and mechanical differences between the original motor and the replacement should be reviewed rather than assuming the replacement is a completely identical part.

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28. Engineering Replacement Notes

The listed engineering replacement is MPL-B320P-SK74AA.

This is significant because the replacement changes the feedback configuration from the original 2000-line incremental encoder arrangement to a single-turn high-resolution encoder configuration.

Therefore, an engineering replacement should be evaluated at the system level.

The motor mounting arrangement, shaft configuration, brake configuration, torque, speed, feedback interface, drive compatibility, and control software configuration should all be checked before the replacement is placed into service.

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29. Why the MPL-B320P-HK74AA Is Useful in Servo Systems

The MPL-B320P-HK74AA combines several features that are useful in demanding motion-control applications.

It has a high 5000 RPM speed rating, a relatively low-inertia rotor, 1.5 kW continuous power, approximately 3.05 N·m continuous torque, and approximately 7.91 N·m peak torque.

The 2000-line incremental encoder provides feedback for closed-loop operation.

The keyless shaft makes it suitable for compatible clamp-style mechanical couplings.

The integral 24 V DC brake provides a convenient holding function for applications where shaft position must be maintained after servo torque is removed.

The right-angle, rotatable DIN connector provides flexibility when designing the machine’s cable routing.

Together, these characteristics make the motor well suited to repetitive, high-speed, servo-controlled industrial machinery.

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30. Technical Summary

Category	Specification
Model	MPL-B320P-HK74AA
Brand	Allen-Bradley
Series	MP-Series MPL
Series Type	Low-Inertia Brushless Servo Motor
Voltage	460 V AC
Rated Speed	5000 RPM
Maximum Speed	5000 RPM
Continuous Torque	3.05 N·m
Peak Torque	7.91 N·m
Continuous Power	1.5 kW
Frame	100 mm
Stack	50.8 mm
Feedback	2000-line incremental encoder
Shaft	Keyless
Brake	Integral 24 V DC
Connector	SpeedTEC DIN
Connector Type	Right-angle
Connector Rotation	180°
Mounting	IEC metric flange
Rotor Inertia	Approx. 0.000078 kg·m²
Approx. Weight	Approx. 4.5 kg
Dimension Reference	100 mm frame × 50.8 mm stack
Overall Dimensions	Verify exact mechanical drawing
Application	Industrial closed-loop servo motion

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31. Final Product Description

The Allen-Bradley MPL-B320P-HK74AA is a 460 V-class, 5000 RPM, low-inertia brushless AC servo motor from the MP-Series MPL family.

Its 100 mm frame, 50.8 mm magnetic stack, approximately 1.5 kW continuous output, 3.05 N·m continuous torque, and 7.91 N·m peak torque make it suitable for a broad range of industrial motion-control applications.

The motor uses a 2000-line incremental encoder for closed-loop feedback and incorporates a keyless shaft arrangement. It also includes an integral 24 V DC brake, making it particularly useful in applications where the shaft or vertical axis must be held when the servo is disabled.

The SpeedTEC DIN right-angle connector with 180° rotation provides additional installation flexibility and helps simplify cable routing in compact machinery.

The 100 mm frame and 50.8 mm stack should be considered the primary catalog dimensions, while the exact overall length, shaft projection, mounting-hole geometry, and connector clearance should be verified from the applicable mechanical drawing before fabrication or replacement.

The MPL-B320P-HK74AA is particularly suitable for packaging machines, indexing systems, material-handling equipment, assembly machines, CNC-related motion, pick-and-place equipment, printing and converting machinery, and other industrial systems that require fast, repeatable closed-loop motion.

For replacement work, the most important parameters to match are the 460 V class, 5000 RPM speed, 3.05 N·m continuous torque, 7.91 N·m peak torque, 100 mm frame, 50.8 mm stack, 2000-line incremental feedback, keyless shaft, and 24 V DC brake.

In practical terms, the MPL-B320P-HK74AA can be regarded as a high-speed, compact, low-inertia servo motor configuration intended for precise and repeatable industrial motion where both encoder feedback and mechanical holding capability are required.