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Allen-Bradley MPL-B320P-MK74AA Servo Motor – Detailed Specifications, Applications, Advantages and Related Models

1. Product Introduction

The Allen-Bradley MPL-B320P-MK74AA is a low-inertia brushless AC rotary servo motor designed for high-speed, precision motion-control applications. It belongs to the MP-Series MPL family and uses a 100 mm frame, 50.8 mm magnet stack, 5000 RPM speed rating, multi-turn high-resolution absolute feedback, a keyless shaft, and an integral 24 V DC holding brake.

This motor is intended for machinery where accurate position control, fast acceleration and deceleration, repeatable motion, and reliable servo feedback are important. The low-inertia design allows the motor to respond rapidly to changes in the commanded motion profile.

The MK74AA configuration is especially useful when the machine requires a keyless shaft together with a built-in holding brake. This makes it different from the closely related MK72AA version, which has a similar motor configuration but does not include the integral brake.

The motor is rated at approximately 1.5 kW continuous power, 5000 RPM, 3.05 N·m continuous torque, and 7.91 N·m peak torque. Its feedback system is a high-resolution multi-turn absolute encoder using Sin/Cos feedback and Hiperface protocol.

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2. Basic Product Parameters

Parameter	Specification
Model	MPL-B320P-MK74AA
Brand	Allen-Bradley
Product Type	AC Rotary Servo Motor
Series	MP-Series MPL Low-Inertia Servo Motor
Motor Type	Brushless Permanent-Magnet AC Servo Motor
Voltage Class	460 V AC class
Product Rating	480 V AC
Rated Power	1.5 kW
Rated Speed	5000 RPM
Maximum Speed	5000 RPM
Continuous Torque	3.05 N·m
Peak Torque	7.91 N·m
Frame Size	100 mm
Magnet Stack Length	50.8 mm
Feedback	Multi-turn High-Resolution Absolute Encoder
Feedback Resolution	1024 Sin/Cos cycles/rev
Feedback Protocol	Hiperface
Shaft	Keyless Shaft Extension
Shaft Seal	No Shaft Seal
Brake	Integral 24 V DC Holding Brake
Connector	SpeedTEC DIN
Connector Style	Right-angle
Connector Rotation	180° rotatable
Mounting	IEC Metric Flange
Mounting Holes	Free Mounting Holes, Type FF
Rotor Inertia	Approx. 0.000078 kg·m²
Maximum Operating Temperature	Approx. 40 °C
Approx. Dimensions	42.799 × 21.692 × 26.01 cm
Approx. Weight	4.5 kg

The core B320P motor data identifies this frame as a 5000 RPM, 1.5 kW servo motor with approximately 3.05 N·m continuous torque and 7.91 N·m peak torque. The B320P family has approximately 0.000078 kg·m² rotor inertia, while the motor configuration uses a 100 mm frame and 50.8 mm magnet stack.

The MK74AA version adds an integral 24 V DC brake to the keyless-shaft, multi-turn absolute encoder configuration. The published physical weight for the B320P family is approximately 4.5 kg, with the exact shipping or packaged weight potentially differing from the motor-only weight.

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3. Brand

Brand: Allen-Bradley

Allen-Bradley is the brand designation used for this industrial automation and motion-control product.

The MPL-B320P-MK74AA carries the Allen-Bradley model designation and belongs to the MP-Series MPL low-inertia servo motor family.

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4. Product Series

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

The MPL series is designed for industrial servo applications where high dynamic response, accurate feedback, compact construction, and controlled rotary motion are required.

The low-inertia construction is particularly valuable for machines that repeatedly accelerate, decelerate, stop, reverse, and reposition.

The B320P configuration is one of the 5000 RPM motor configurations in the MPL family. Its basic performance level is approximately 1.5 kW, 3.05 N·m continuous torque, and 7.91 N·m peak torque.

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5. Model Number Explanation

The complete model number contains several configuration identifiers.

Model Code	Description
MPL	Low-inertia brushless servo motor family
B	460 V-class motor family
3	100 mm frame class
20	50.8 mm magnet stack
P	5000 RPM speed class
M	Multi-turn high-resolution absolute encoder
K	Keyless shaft extension
7	SpeedTEC DIN right-angle connector, 180° rotatable
4	24 V DC integral holding brake
AA	Standard catalog configuration

The final “74AA” portion is particularly important because it identifies the brake-equipped configuration.

The K indicates a keyless shaft, while the 4 identifies the integral 24 V DC brake.

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6. Detailed Technical Specifications

Technical Parameter	Specification
Model	MPL-B320P-MK74AA
Servo Type	Rotary AC Servo Motor
Motor Construction	Low-Inertia Brushless
Voltage Class	460 V AC
Product Voltage Rating	480 V AC
Continuous Power	1.5 kW
Rated Speed	5000 RPM
Maximum Speed	5000 RPM
Continuous Torque	3.05 N·m
Peak Torque	7.91 N·m
Frame Size	100 mm
Magnet Stack	50.8 mm
Feedback	Absolute Multi-Turn
Encoder	High-Resolution Sin/Cos
Feedback Resolution	1024 cycles/rev
Feedback Protocol	Hiperface
Shaft Type	Keyless
Shaft Seal	None
Brake	24 V DC Holding Brake
Connector	SpeedTEC DIN
Connector Orientation	Right-angle
Connector Rotation	180°
Mounting	IEC Metric Flange
Rotor Inertia	Approx. 0.000078 kg·m²
Approx. Dimensions	42.799 × 21.692 × 26.01 cm
Approx. Weight	4.5 kg

The published product description specifically identifies the MK74AA as a 460 V-class, 100 mm-frame, 50.8 mm-stack, 5000 RPM motor with multi-turn high-resolution absolute feedback, keyless shaft, SpeedTEC DIN connector, and 24 V DC brake.

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7. Motor Power

The MPL-B320P-MK74AA has a continuous rated output of approximately 1.5 kW.

A 1.5 kW servo motor is well suited to many medium-duty precision motion applications where the machine requires more dynamic performance than a conventional fixed-speed motor.

The motor does not simply operate at one fixed speed. It is designed to work with a servo drive that continuously controls torque, velocity, and position.

This allows the motor to accelerate quickly, decelerate in a controlled manner, stop at defined positions, and synchronize its movement with other machine axes.

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8. Rated Speed and High-Speed Operation

The motor has a rated speed of 5000 RPM and a maximum speed of 5000 RPM.

This high-speed characteristic is useful in applications where short machine cycles are important.

A 5000 RPM servo motor can also allow machine designers to use suitable mechanical transmission ratios to achieve the required linear or rotary output speed.

Typical applications include indexing mechanisms, high-speed packaging machinery, rotary positioning systems, material handling equipment, and other automated production machinery.

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9. Continuous Torque

The continuous torque rating is approximately 3.05 N·m.

Continuous torque represents the motor’s ability to produce sustained torque under appropriate operating conditions.

Torque Parameter	Value
Model	MPL-B320P-MK74AA
Continuous Torque	3.05 N·m
Peak Torque	7.91 N·m
Rated Power	1.5 kW
Rated Speed	5000 RPM
Rotor Inertia	0.000078 kg·m²
Weight	Approx. 4.5 kg
Dimensions	Approx. 42.799 × 21.692 × 26.01 cm

The continuous torque value is especially important when calculating the required motor size for a machine.

The machine designer should consider the complete motion profile rather than selecting the motor from continuous torque alone.

Acceleration torque, friction, load inertia, transmission efficiency, duty cycle, and peak torque requirements all need to be considered.

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10. Peak Torque

The peak torque capability is approximately 7.91 N·m.

Peak torque is useful during short periods of rapid acceleration, deceleration, positioning, or disturbance recovery.

A servo motor can therefore provide significantly more short-duration torque than its continuous operating torque.

The actual allowable peak torque duration depends on the complete servo system, operating conditions, drive configuration, motor temperature, and motion profile.

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11. Low-Inertia Construction

The rotor inertia is approximately 0.000078 kg·m² for the B320P configuration.

Low rotor inertia is one of the main reasons this motor is suitable for fast motion.

When the motor has low rotating inertia, the servo system can change speed quickly.

This is particularly useful in machines that perform repeated indexing.

For example, a packaging machine may accelerate a mechanism, move it to a specific position, stop, reverse, and repeat the process hundreds or thousands of times during a production cycle.

A low-inertia servo motor can respond effectively to these repeated motion commands.

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12. Multi-Turn Absolute Encoder

The MPL-B320P-MK74AA uses a multi-turn high-resolution absolute encoder.

The encoder uses Sin/Cos feedback with approximately 1024 cycles per revolution and Hiperface protocol.

The multi-turn capability provides position information over multiple shaft revolutions.

This is useful in machine axes where absolute position information is important.

The encoder also allows the servo drive to monitor motor position continuously and use the feedback for closed-loop control.

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13. Advantages of Absolute Feedback

Absolute feedback provides several practical advantages for motion-control systems.

The controller receives detailed position information from the motor feedback system.

This supports accurate positioning and repeatable machine movement.

For equipment that must return to known positions after a power cycle or machine restart, an absolute feedback system can be particularly useful depending on the complete controller and drive configuration.

The multi-turn capability is also valuable when the motor shaft rotates through multiple revolutions during normal machine operation.

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14. Keyless Shaft

The K in the model number indicates the keyless shaft configuration.

Unlike a conventional keyed motor shaft, the shaft does not use a mechanical key.

The motor can therefore be paired with an appropriate clamping hub, precision coupling, shrink-fit arrangement, or other suitable keyless mechanical transmission component.

Mechanical Parameter	Specification
Model	MPL-B320P-MK74AA
Shaft Type	Keyless
Shaft Key	None
Shaft Seal	None
Frame	100 mm
Stack	50.8 mm
Brake	24 V DC
Mounting	IEC Metric Flange
Connector	SpeedTEC DIN
Weight	Approx. 4.5 kg
Dimensions	Approx. 42.799 × 21.692 × 26.01 cm

The coupling must be correctly selected for the motor’s speed, torque, radial load, axial load, acceleration, and application duty.

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15. Integral 24 V DC Brake

One of the most important features of the MK74AA configuration is its 24 V DC holding brake.

The brake is integrated into the motor assembly and is intended primarily for holding applications rather than for routine dynamic stopping.

This distinction is important.

The servo drive normally controls the motor electrically for normal acceleration and deceleration.

The mechanical brake is generally used to hold the axis when the motor is not energized or when the machine requires an additional holding function.

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16. Applications Where the Brake Is Useful

The integral brake can be particularly useful on vertical axes.

For example, a vertical machine axis may carry a load that could move downward under gravity when motor torque is removed.

A holding brake can provide mechanical holding capability when the servo system is disabled.

Typical applications include:

• Vertical positioning axes
• Lift mechanisms
• Automated handling systems
• Vertical transfer systems
• Machine-tool vertical axes
• Robotic lifting mechanisms
• Material positioning systems
• Equipment requiring stationary holding during shutdown

The brake should not be treated as the only safety measure for personnel protection. The complete machine safety design must determine the appropriate protective measures.

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17. SpeedTEC DIN Connector

The motor uses a SpeedTEC DIN right-angle connector.

The connector can be rotated through approximately 180 degrees, providing flexibility during installation.

This is useful when the motor is installed in a compact machine where cable space is limited.

The right-angle connector can help keep cables closer to the machine structure and away from moving components.

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18. Mechanical Dimensions

The motor belongs to the 100 mm frame class and uses a 50.8 mm magnet stack.

For overall product planning, the approximate physical envelope is:

• Length: 42.799 cm
• Width: 21.692 cm
• Height: 26.01 cm

Dimension Parameter	Specification
Model	MPL-B320P-MK74AA
Frame Size	100 mm
Magnet Stack	50.8 mm
Overall Length	Approx. 42.799 cm
Overall Width	Approx. 21.692 cm
Overall Height	Approx. 26.01 cm
Mounting Type	IEC Metric Flange
Shaft Type	Keyless
Connector	Right-angle SpeedTEC DIN
Brake	24 V DC
Weight	Approx. 4.5 kg

These overall dimensions should be treated as product-envelope information.

For final machine design, the applicable mechanical drawing should be used to confirm mounting-hole locations, shaft dimensions, connector clearance, and installation tolerances.

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19. Weight

The B320P motor family is approximately 4.5 kg in the published selection data.

The brake-equipped MK74AA configuration is heavier than the comparable no-brake configuration because the motor includes the integral holding brake.

Weight Information	Value
Model	MPL-B320P-MK74AA
Approx. Motor Weight	4.5 kg
Frame Size	100 mm
Stack Length	50.8 mm
Power	1.5 kW
Speed	5000 RPM
Continuous Torque	3.05 N·m
Dimensions	Approx. 42.799 × 21.692 × 26.01 cm

When designing a moving machine axis, the motor weight should be included in the total moving mass calculation.

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20. Electrical Parameters

Electrical Parameter	Specification
Model	MPL-B320P-MK74AA
Motor Type	Brushless AC Servo
Voltage Class	460 V AC
Product Rating	480 V AC
Rated Power	1.5 kW
Rated Speed	5000 RPM
Maximum Speed	5000 RPM
Continuous Torque	3.05 N·m
Peak Torque	7.91 N·m
Feedback	Absolute Multi-Turn
Encoder	Sin/Cos High Resolution
Encoder Resolution	1024 cycles/rev
Feedback Protocol	Hiperface
Brake Voltage	24 V DC
Brake	Integral Holding Brake
Rotor Inertia	Approx. 0.000078 kg·m²
Weight	Approx. 4.5 kg
Dimensions	Approx. 42.799 × 21.692 × 26.01 cm

The motor should be operated with a compatible servo drive and motion-control system.

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21. Typical Applications

Packaging Machinery

Packaging equipment is one of the natural applications for high-speed servo motors.

The motor can be used for indexing, feeding, cutting, positioning, sealing mechanisms, and synchronized rotary movement.

The 5000 RPM speed capability supports rapid machine cycles, while the absolute encoder provides detailed feedback for precise motion.

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Pick-and-Place Equipment

Pick-and-place machinery often requires rapid acceleration and deceleration.

The low rotor inertia helps the motor respond quickly to motion commands.

The absolute encoder supports precise position feedback, while the brake can be useful when an axis must remain stationary during certain operating conditions.

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Assembly Machinery

Automated assembly equipment frequently contains multiple synchronized servo axes.

The MPL-B320P-MK74AA can be used for rotary positioning, indexing, transfer mechanisms, actuator systems, and other controlled machine movements.

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Material Handling

Material-handling systems often require controlled positioning rather than simple continuous rotation.

The motor can be used in transfer systems, lifting mechanisms, indexing equipment, sorting machinery, and automated handling equipment.

The integral brake can be particularly useful for applications involving vertical movement.

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Conveyor Positioning

Servo-controlled conveyors can require precise acceleration, deceleration, indexing, and synchronization.

The MPL-B320P-MK74AA can provide controlled motion for these applications where the required torque and speed fall within the motor’s operating range.

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Printing Equipment

Printing machinery can require accurate synchronization between rollers and other moving components.

The high-speed servo motor can be used for selected roller drives, positioning mechanisms, feeding systems, and synchronized rotary axes.

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Labeling Machinery

Labeling machines frequently require rapid, repeatable positioning.

The motor’s 5000 RPM speed capability and low-inertia construction can support high-cycle motion.

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Machine Tools

The motor can be used for selected auxiliary machine-tool axes, indexing systems, tool positioning mechanisms, and other servo-controlled functions.

The actual selection should be based on required torque, speed, inertia, acceleration, duty cycle, and mechanical configuration.

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22. Main Product Advantages

22.1 High-Speed Performance

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

This can be useful when the machine needs rapid rotary motion or high-frequency positioning.

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22.2 Low Rotor Inertia

The low-inertia construction allows fast changes in motor speed.

This can improve the dynamic response of repetitive positioning applications.

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22.3 Multi-Turn Absolute Feedback

The multi-turn absolute encoder provides detailed position information.

This is useful for machines that require accurate position tracking across multiple motor revolutions.

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22.4 Integrated Holding Brake

The 24 V DC brake is a major advantage when the application requires mechanical holding.

This can simplify the design of vertical or gravity-loaded axes.

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22.5 Keyless Shaft

The keyless shaft allows compatibility with appropriate clamping and precision coupling systems.

This can be advantageous for compact machine transmissions.

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22.6 Compact Frame

The 100 mm frame provides a compact physical package for a 1.5 kW, 5000 RPM servo motor.

This can help machine designers make efficient use of installation space.

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22.7 Flexible Connector Orientation

The 180-degree rotatable right-angle connector provides flexibility during installation.

This can make cable routing easier in compact machinery.

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23. Applications Where the MK74AA Is Particularly Useful

The combination of keyless shaft, absolute feedback, and integral brake makes this model useful for machines where both precise motion and holding capability are required.

Examples include:

• Vertical positioning machines
• Lift mechanisms
• Automated transfer systems
• Robotic axes
• Packaging machinery
• Indexing machines
• Assembly machinery
• Material handling equipment
• High-speed positioning systems
• Automated production machinery

The brake-equipped configuration can be particularly useful when the machine axis needs to remain stationary after servo power is removed.

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24. Installation Considerations

The motor should be installed on a rigid and properly aligned machine structure.

The mounting surface should be capable of handling the motor’s dynamic reaction forces.

The driven shaft and motor shaft should be accurately aligned.

Improper alignment can create excessive radial or axial loads and can reduce mechanical component life.

The keyless coupling should be selected for the motor’s rated speed and torque.

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25. Brake Control Considerations

The integral brake should be controlled according to the complete servo system’s requirements.

The brake is generally used as a holding device rather than as the primary method of stopping a high-speed rotating load.

A typical motion sequence may involve:

1. Servo drive establishes motor control.
2. Motor develops sufficient holding torque.
3. Brake is released.
4. Axis begins controlled movement.
5. Axis decelerates under servo control.
6. Motor reaches the required position.
7. Servo torque is established for holding.
8. Brake can then be applied when appropriate.

The exact sequence should follow the requirements of the drive, controller, machine, and safety system.

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26. Servo Tuning

Good mechanical installation is only one part of achieving satisfactory servo performance.

The drive must also be correctly configured and tuned.

Important factors include:

• Load inertia
• Motor inertia
• Gear ratio
• Coupling stiffness
• Mechanical backlash
• Friction
• Acceleration rate
• Deceleration rate
• Position-loop gain
• Velocity-loop gain
• Resonance
• Following error

The low-inertia motor can respond quickly, but the machine mechanics must also be capable of handling the resulting dynamic response.

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27. Maintenance

Routine inspection should include the motor housing, connector, cable, mounting hardware, coupling, and brake operation.

Abnormal noise or vibration should be investigated promptly.

The motor should also be checked for excessive temperature.

The keyless shaft coupling should be inspected according to the coupling manufacturer’s requirements.

The brake should be checked as part of the machine’s maintenance procedure where the application depends on the holding function.

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28. Replacement Considerations

When replacing an existing motor, the complete model number should be matched.

Matching only “MPL-B320P” is not sufficient because different configurations can have different shaft styles, feedback systems, brakes, and connectors.

For the MK74AA, the following characteristics are especially important:

• 460 V-class motor
• 100 mm frame
• 50.8 mm stack
• 5000 RPM
• 1.5 kW
• Multi-turn absolute encoder
• Keyless shaft
• 24 V DC brake
• SpeedTEC DIN connector

A replacement motor should match the servo drive’s supported motor configuration.

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29. Five Closely Related Models

The following models are closely related to the MPL-B320P-MK74AA and can be considered when evaluating alternative configurations.

Model	Voltage	Frame	Stack	Speed	Power	Continuous Torque	Feedback	Shaft	Brake	Approx. Weight	Dimensions
MPL-B320P-MK74AA	460 V class	100 mm	50.8 mm	5000 RPM	1.5 kW	3.05 N·m	Multi-turn absolute	Keyless	24 V DC	4.5 kg	42.799 × 21.692 × 26.01 cm
MPL-B320P-MK72AA	460 V class	100 mm	50.8 mm	5000 RPM	1.5 kW	3.05 N·m	Multi-turn absolute	Keyless	No	Approx. 3.7 kg	Same B320P envelope class
MPL-B320P-MJ74AA	460 V class	100 mm	50.8 mm	5000 RPM	1.5 kW	3.05 N·m	Multi-turn absolute	Keyed	24 V DC	Verify exact unit	Same B320P envelope class
MPL-B320P-HK74AA	460 V class	100 mm	50.8 mm	5000 RPM	1.5 kW	3.05 N·m	Incremental	Keyless	24 V DC	Verify exact unit	Same B320P envelope class
MPL-B320P-HJ74AA	460 V class	100 mm	50.8 mm	5000 RPM	1.5 kW	3.05 N·m	Incremental	Keyed	24 V DC	Verify exact unit	Same B320P envelope class

The MPL-B320P-MK72AA is the closest no-brake alternative.

The MPL-B320P-MJ74AA is the closest keyed-shaft alternative.

The MPL-B320P-HK74AA and MPL-B320P-HJ74AA are useful alternatives when the control system uses incremental rather than multi-turn absolute feedback.

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30. Same-Series Comparison

Feature	MPL-B320P-MK74AA	MPL-B320P-MK72AA	MPL-B320P-MJ74AA	MPL-B320P-HK74AA	MPL-B320P-HJ74AA
Frame	100 mm	100 mm	100 mm	100 mm	100 mm
Stack	50.8 mm	50.8 mm	50.8 mm	50.8 mm	50.8 mm
Speed	5000 RPM	5000 RPM	5000 RPM	5000 RPM	5000 RPM
Power	1.5 kW	1.5 kW	1.5 kW	1.5 kW	1.5 kW
Continuous Torque	3.05 N·m	3.05 N·m	3.05 N·m	3.05 N·m	3.05 N·m
Peak Torque	7.91 N·m	7.91 N·m	7.91 N·m	7.91 N·m	7.91 N·m
Feedback	Multi-turn absolute	Multi-turn absolute	Multi-turn absolute	Incremental	Incremental
Shaft	Keyless	Keyless	Keyed	Keyless	Keyed
Brake	24 V DC	None	24 V DC	24 V DC	24 V DC
Rotor Inertia	0.000078 kg·m²	0.000078 kg·m²	0.000078 kg·m²	Approx. 0.000078 kg·m²	Approx. 0.000078 kg·m²
Weight	4.5 kg	Approx. 3.7 kg	Verify exact unit	Verify exact unit	Verify exact unit
Dimensions	42.799 × 21.692 × 26.01 cm	Same family envelope	Same family envelope	Same family envelope	Same family envelope

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31. Five Other Popular Allen-Bradley Servo Motor Models

The following models provide useful comparison points within the broader MPL servo motor family.

Model	Voltage Class	Motor Class	Speed	Power	Continuous Torque	Feedback	Shaft	Brake	Approx. Weight	Dimensions
MPL-B310P-MJ74AA	460 V	B310P	5000 RPM	0.77 kW	1.58 N·m	Multi-turn absolute	Keyed	24 V DC	Approx. 2.7 kg	B310P frame envelope
MPL-B320P-HK74AA	460 V	B320P	5000 RPM	1.5 kW	3.05 N·m	Incremental	Keyless	24 V DC	Approx. 4.5 kg class	B320P envelope
MPL-B330P-MK74AA	460 V	B330P	5000 RPM	1.8 kW	4.18 N·m	Multi-turn absolute	Keyless	24 V DC	Approx. 4.6 kg	B330P envelope
MPL-B420P-MJ74AA	460 V	B420P	5000 RPM	1.9 kW	4.74 N·m	Multi-turn absolute	Keyed	24 V DC	Approx. 4.3 kg	B420P envelope
MPL-B430P-MJ72AA	460 V	B430P	5000 RPM	2.2 kW	6.55 N·m	Multi-turn absolute	Keyed	No	Approx. 5.5 kg	B430P envelope

The B310P through B430P configurations cover progressively higher torque and power levels while maintaining the 5000 RPM speed class. Published B-series data lists approximately 0.77 kW for B310P, 1.5 kW for B320P, 1.8 kW for B330P, 1.9 kW for B420P, and 2.2 kW for B430P.

The exact weight and dimensional envelope should always be checked against the specific motor configuration before using one of these models as a direct mechanical replacement.

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32. B-Series Performance Comparison

Model	Rated Speed	Continuous Torque	Peak Torque	Power	Rotor Inertia	Approx. Weight
MPL-B310P	5000 RPM	1.58 N·m	3.61 N·m	0.77 kW	0.000044 kg·m²	2.7 kg
MPL-B320P	5000 RPM	3.05 N·m	7.91 N·m	1.5 kW	0.000078 kg·m²	3.7–4.5 kg configuration dependent
MPL-B330P	5000 RPM	4.18 N·m	11.1 N·m	1.8 kW	0.00012 kg·m²	4.6 kg
MPL-B420P	5000 RPM	4.74 N·m	13.5 N·m	1.9 kW	0.00026 kg·m²	4.3 kg
MPL-B430P	5000 RPM	6.55 N·m	19.8 N·m	2.2 kW	0.00038 kg·m²	5.5 kg

These figures are useful for understanding where the B320P sits within the broader motor family.

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33. MPL-B320P-MK74AA vs. MPL-B320P-MK72AA

These two models are very closely related.

The primary difference is the integral brake.

Parameter	MPL-B320P-MK74AA	MPL-B320P-MK72AA
Power	1.5 kW	1.5 kW
Speed	5000 RPM	5000 RPM
Continuous Torque	3.05 N·m	3.05 N·m
Peak Torque	7.91 N·m	7.91 N·m
Feedback	Multi-turn absolute	Multi-turn absolute
Shaft	Keyless	Keyless
Brake	24 V DC	None
Frame	100 mm	100 mm
Stack	50.8 mm	50.8 mm
Rotor Inertia	0.000078 kg·m²	0.000078 kg·m²
Weight	Approx. 4.5 kg	Approx. 3.7 kg
Dimensions	42.799 × 21.692 × 26.01 cm	Same B320P family envelope

For a vertical or gravity-loaded axis, the brake-equipped MK74AA configuration provides a different mechanical holding capability than the no-brake MK72AA.

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34. MPL-B320P-MK74AA vs. MPL-B320P-MJ74AA

The major difference between these models is the shaft configuration.

Parameter	MPL-B320P-MK74AA	MPL-B320P-MJ74AA
Power	1.5 kW	1.5 kW
Speed	5000 RPM	5000 RPM
Continuous Torque	3.05 N·m	3.05 N·m
Feedback	Multi-turn absolute	Multi-turn absolute
Shaft	Keyless	Keyed
Brake	24 V DC	24 V DC
Frame	100 mm	100 mm
Stack	50.8 mm	50.8 mm
Weight	Approx. 4.5 kg	Verify exact unit
Dimensions	42.799 × 21.692 × 26.01 cm	Same B320P family envelope

If the machine uses a clamping-type coupling, the MK74AA may be the appropriate mechanical configuration.

If the machine transmission requires a conventional keyed connection, the MJ74AA configuration may be more appropriate.

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35. MPL-B320P-MK74AA vs. MPL-B320P-HK74AA

These two configurations both use a keyless shaft and a 24 V DC brake.

Their main difference is the feedback system.

Parameter	MPL-B320P-MK74AA	MPL-B320P-HK74AA
Power	1.5 kW	1.5 kW
Speed	5000 RPM	5000 RPM
Continuous Torque	3.05 N·m	3.05 N·m
Shaft	Keyless	Keyless
Brake	24 V DC	24 V DC
Feedback	Multi-turn absolute	Incremental
Frame	100 mm	100 mm
Stack	50.8 mm	50.8 mm
Rotor Inertia	0.000078 kg·m²	Approx. 0.000078 kg·m²
Weight	Approx. 4.5 kg	Verify exact unit
Dimensions	42.799 × 21.692 × 26.01 cm	Same B320P family envelope

The feedback type must match the servo drive and controller configuration.

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36. Practical Selection Guide

Application Requirement	Suggested Configuration
Keyless shaft + absolute multi-turn feedback + brake	MPL-B320P-MK74AA
Keyless shaft + absolute multi-turn feedback + no brake	MPL-B320P-MK72AA
Keyed shaft + absolute multi-turn feedback + brake	MPL-B320P-MJ74AA
Keyless shaft + incremental feedback + brake	MPL-B320P-HK74AA
Keyed shaft + incremental feedback + brake	MPL-B320P-HJ74AA
Lower power requirement	MPL-B310P family
Higher torque requirement	MPL-B330P / B420P / B430P family

This table is intended as a configuration guide rather than a substitute for complete motor sizing.

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37. Machine Design Advantages

The MPL-B320P-MK74AA offers several useful characteristics for machine builders.

The first is its combination of high speed and low inertia.

The second is the high-resolution multi-turn feedback.

The third is the integral holding brake.

The fourth is the keyless shaft arrangement.

The fifth is the compact 100 mm frame.

Together, these features make the motor suitable for machines where space, response time, positioning accuracy, and holding capability are all important.

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38. Why the Integral Brake Matters

The integral brake is not simply an additional accessory.

It can influence the entire machine architecture.

A vertical axis may require a holding mechanism because the load can move when motor torque is removed.

With an integral motor brake, the machine can incorporate the holding function directly into the servo motor assembly.

This can reduce the need for a separate mechanical brake arrangement, depending on the application and safety requirements.

The brake should still be correctly controlled and incorporated into the machine’s safety design.

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39. Why the Keyless Shaft Matters

The keyless shaft can be advantageous when the machine uses precision clamping connections.

It eliminates the need to align a mechanical key with a keyway during coupling installation.

For suitable coupling systems, this can provide a compact and precise connection between the servo motor and driven mechanism.

However, the coupling must be correctly installed and torqued.

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40. Maintenance and Service Considerations

The motor should be kept clean and protected from excessive contamination.

The feedback connector should remain properly secured.

Motor cables should be inspected for damage.

The mechanical coupling should be checked periodically.

The brake should be tested according to the machine’s maintenance procedure when the holding function is important.

Unusual motor temperature, noise, vibration, or position error should be investigated rather than ignored.

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41. Final Technical Specification Table

Category	Specification
Model	MPL-B320P-MK74AA
Brand	Allen-Bradley
Series	MP-Series MPL
Product Type	Low-Inertia Brushless AC Rotary Servo Motor
Voltage Class	460 V AC
Product Rating	480 V AC
Rated Power	1.5 kW
Rated Speed	5000 RPM
Maximum Speed	5000 RPM
Continuous Torque	3.05 N·m
Peak Torque	7.91 N·m
Frame Size	100 mm
Magnet Stack Length	50.8 mm
Feedback	Multi-Turn Absolute
Encoder	High-Resolution Sin/Cos
Encoder Resolution	1024 cycles/rev
Protocol	Hiperface
Shaft	Keyless
Shaft Seal	None
Brake	24 V DC Integral Holding Brake
Connector	SpeedTEC DIN
Connector Type	Right-Angle
Connector Rotation	180°
Mounting	IEC Metric Flange
Rotor Inertia	Approx. 0.000078 kg·m²
Approx. Dimensions	42.799 × 21.692 × 26.01 cm
Approx. Weight	4.5 kg
Typical Use	Precision Industrial Motion Control

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42. Final Product Overview

The Allen-Bradley MPL-B320P-MK74AA is a 1.5 kW, 5000 RPM low-inertia AC servo motor designed for demanding industrial motion-control applications.

Its 100 mm frame and 50.8 mm magnet stack provide a compact motor package while maintaining useful torque and high-speed performance.

The motor provides approximately 3.05 N·m continuous torque and 7.91 N·m peak torque.

The low rotor inertia of approximately 0.000078 kg·m² supports fast acceleration and deceleration.

The multi-turn high-resolution absolute encoder provides detailed position feedback and is suitable for precision closed-loop motion control.

The keyless shaft provides compatibility with suitable clamping and precision coupling systems.

The integral 24 V DC holding brake is one of the most useful characteristics of the MK74AA configuration, particularly for applications where the axis must remain mechanically held when motor torque is removed.

The SpeedTEC DIN right-angle connector provides additional flexibility during installation, while the 180-degree rotation capability can help with cable routing in compact machine structures.

Overall, the MPL-B320P-MK74AA is a well-defined servo configuration for machines requiring a combination of high speed, low inertia, absolute multi-turn feedback, keyless mechanical connection, and integral holding-brake capability.

When selecting this motor as a replacement, the complete model number should be matched carefully. The shaft style, feedback type, brake configuration, voltage class, frame size, stack length, connector type, and mechanical dimensions should all be checked before installation.