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Allen-Bradley MPL-B320P-MJ74AA Servo Motor

1. Product Introduction

The Allen-Bradley MPL-B320P-MJ74AA is a 460 V-class, high-speed, low-inertia brushless AC rotary servo motor designed for industrial motion-control systems.

It belongs to the MP-Series MPL Low-Inertia Brushless Servo Motor family and is configured with a 100 mm frame, 50.8 mm magnetic stack, 5000 RPM rated speed, multi-turn high-resolution absolute feedback, keyed shaft extension, a right-angle SpeedTEC DIN connector, and an integral 24 V DC brake.

The motor is intended for machinery requiring controlled acceleration, deceleration, positioning, indexing, synchronization, and repeatable rotary or linear movement.

The B320P motor platform provides approximately 1.5 kW of rated power, approximately 3.05 N·m of continuous torque, and a maximum speed of approximately 5000 RPM.

One of the most important features of the MPL-B320P-MJ74AA is its multi-turn high-resolution absolute encoder. This feedback arrangement allows the servo control system to monitor motor position with high resolution across multiple revolutions.

The motor also incorporates a 24 V DC holding brake, making this particular configuration suitable for applications where the shaft or load must be mechanically held after servo torque is removed.

The keyed shaft provides a conventional mechanical interface for compatible couplings, pulleys, gears, and other transmission components.

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2. Basic Product Parameters

Parameter	Specification
Model	MPL-B320P-MJ74AA
Brand	Allen-Bradley
Product Family	MP-Series MPL
Product Series	MPL Low-Inertia Brushless Servo Motors
Product Type	Brushless AC Rotary Servo Motor
Voltage Class	460 V AC
Nominal Supply Class	480 V AC
Rated Motor Power	1.5 kW
Rated Speed	5000 RPM
Maximum Speed	5000 RPM
Continuous Torque	3.05 N·m
Peak / Stall Torque Reference	Approximately 7.91 N·m
Frame Size	100 mm
Frame Designation	Frame 3
Magnetic Stack Length	50.8 mm
Stack Designation	20
Feedback	Multi-turn high-resolution absolute encoder
Shaft	Keyed shaft extension
Brake	Integral 24 V DC brake
Connector	SpeedTEC DIN
Connector Type	Right-angle
Connector Rotation	180° rotatable
Mounting	IEC metric flange
Mounting Hole Style	Free mounting holes, Type FF
Shaft Seal	No shaft seal
Rotor Inertia	Approximately 0.000078 kg·m²
Overall Length	Approximately 42.799 cm
Overall Width	Approximately 21.692 cm
Overall Height	Approximately 26.01 cm
Approximate Motor Weight	5.509 kg
Dimension Unit	cm
Weight Unit	kg
Motor Construction	Brushless permanent-magnet servo
Application	Industrial closed-loop motion control

The current product information identifies the motor as a 480 V AC rotary servo motor and lists physical dimensions of approximately 42.799 cm length × 21.692 cm width × 26.01 cm height, with a listed weight of 5.509 kg.

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3. Brand

Brand: Allen-Bradley

The MPL-B320P-MJ74AA is part of the Allen-Bradley servo motor product range.

For industrial catalog classification, it 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 permanent-magnet brushless servo motors intended for industrial motion-control applications.

The series is available in different frame sizes, stack lengths, speed ratings, feedback configurations, shaft arrangements, connector configurations, and brake options.

The MPL-B320P-MJ74AA represents the following general configuration:

• 460 V-class motor.
• 100 mm frame.
• 50.8 mm magnetic stack.
• 5000 RPM speed class.
• Multi-turn high-resolution absolute encoder.
• Keyed shaft.
• SpeedTEC DIN right-angle connector.
• 24 V DC integral brake.
• IEC metric mounting.

This combination makes the model particularly useful when both high-speed servo motion and mechanical holding capability are required.

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5. Model Number Explanation

The catalog number is:

MPL-B320P-MJ74AA

The individual sections of the catalog number identify the main motor configuration.

Code	Description
MPL	MPL low-inertia brushless servo motor family
B	460 V-class motor configuration
3	Frame 3 / 100 mm frame
20	50.8 mm magnetic stack
P	5000 RPM speed class
M	Multi-turn high-resolution absolute encoder
J	Keyed shaft extension
7	SpeedTEC DIN right-angle connector, 180° rotatable
4	Integral 24 V DC brake
AA	Standard catalog configuration designation

The M, J, and 4 portions are particularly important when comparing similar motors.

The M designation identifies the multi-turn high-resolution feedback configuration.

The J designation identifies the keyed shaft.

The 4 designation identifies the brake-equipped configuration.

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6. Detailed Technical Specifications

Technical Parameter	MPL-B320P-MJ74AA
Model	MPL-B320P-MJ74AA
Motor Type	Low-inertia brushless AC servo
Voltage	460 V class
Supply Class	480 V AC
Rated Power	1.5 kW
Rated Speed	5000 RPM
Maximum Speed	5000 RPM
Continuous Torque	3.05 N·m
Peak Torque	Approximately 7.91 N·m
Frame Size	100 mm
Frame Number	3
Magnetic Stack	50.8 mm
Stack Number	20
Feedback	Multi-turn high-resolution absolute encoder
Feedback Type	Absolute
Shaft	Keyed
Brake	24 V DC integral brake
Connector	SpeedTEC DIN
Connector Orientation	Right-angle
Connector Rotation	180°
Mounting Flange	IEC metric
Mounting Holes	Free mounting holes, Type FF
Shaft Seal	None
Rotor Inertia	Approx. 7.8 × 10⁻⁵ kg·m²
Overall Length	Approx. 42.799 cm
Overall Width	Approx. 21.692 cm
Overall Height	Approx. 26.01 cm
Weight	Approx. 5.509 kg

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7. Motor Power

The MPL-B320P-MJ74AA is a 1.5 kW servo motor.

The power rating represents the motor’s continuous rated output under its specified operating conditions.

In a servo application, power alone does not determine whether a motor is correctly sized.

The machine designer should also consider continuous torque, peak torque, RMS torque, acceleration requirements, deceleration requirements, operating speed, load inertia, duty cycle, and thermal conditions.

For this model, the approximately 3.05 N·m continuous torque and 5000 RPM speed are especially important when evaluating the motor for a specific axis.

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8. Continuous and Peak Torque

Torque Parameter	Value
Model	MPL-B320P-MJ74AA
Continuous Torque	3.05 N·m
Peak Torque Reference	Approx. 7.91 N·m
Rated Power	1.5 kW
Rated Speed	5000 RPM
Maximum Speed	5000 RPM

The continuous torque indicates the motor’s normal continuous torque capability under the specified operating conditions.

The higher peak torque capability is intended for short-duration motion requirements such as acceleration, deceleration, positioning correction, and transient load conditions.

A servo axis normally operates below its peak torque for much of its duty cycle.

The actual allowable torque profile depends on motor temperature, duty cycle, drive settings, ambient conditions, and the specific motion profile.

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9. 5000 RPM High-Speed Operation

The MPL-B320P-MJ74AA is a 5000 RPM-class servo motor.

High-speed operation is useful in machinery where rapid rotary movement and short cycle times are important.

Typical applications include:

• High-speed indexing.
• Packaging.
• Feeding.
• Cutting.
• Conveyor synchronization.
• Rotary positioning.
• Automated assembly.
• Printing and converting.
• Pick-and-place equipment.

When the motor is connected to a gearbox, ball screw, timing belt, pulley, or other transmission, the actual machine-axis speed is determined by the transmission ratio.

The 5000 RPM rating therefore gives the machine designer considerable flexibility in selecting the mechanical transmission.

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10. Multi-Turn High-Resolution Absolute Encoder

The M configuration identifies the multi-turn high-resolution absolute feedback arrangement.

This is one of the main differences between the MPL-B320P-MJ74AA and versions equipped with incremental feedback.

The absolute encoder supplies position information to the servo control system.

The multi-turn characteristic is especially useful when the motor shaft rotates through multiple revolutions during normal machine operation.

This is valuable in long-travel axes, rotary mechanisms, positioning systems, and applications where the controller needs to distinguish accumulated shaft position.

The high-resolution feedback also supports precise servo velocity and position control when used with a compatible drive and controller.

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11. Benefits of Absolute Multi-Turn Feedback

The absolute multi-turn encoder can provide several practical benefits.

Accurate Position Information

The controller receives detailed information about the actual motor shaft position.

Multi-Revolution Position Tracking

The system can distinguish shaft position across multiple revolutions.

Suitable for Complex Motion

Multi-turn feedback is useful for long-travel axes and rotary mechanisms where a single motor revolution is only part of the complete machine movement.

High-Resolution Servo Control

The feedback system provides detailed position information for closed-loop control.

Reduced Dependence on Simple Incremental Feedback

For machines designed specifically around absolute feedback, the controller can use absolute position information as part of the machine’s startup and positioning strategy.

The actual behavior depends on the selected servo drive, controller, feedback interface, and machine software.

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12. Keyed Shaft

The MPL-B320P-MJ74AA uses a keyed shaft extension.

The keyed shaft provides a conventional mechanical connection for compatible couplings and transmission components.

It can be used with suitable:

• Couplings.
• Pulleys.
• Gears.
• Timing-belt systems.
• Mechanical actuators.
• Rotary indexing mechanisms.

The shaft dimensions and keyway dimensions should always be checked against the applicable mechanical drawing before selecting a coupling.

A motor with the same electrical specifications but a different shaft arrangement should not automatically be considered a direct mechanical replacement.

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13. Integral 24 V DC Brake

The 4 in the catalog number indicates the integral brake configuration.

The MPL-B320P-MJ74AA includes a 24 V DC brake.

The brake is primarily intended as a holding device.

This makes the motor particularly useful for applications where the axis must remain stationary after motor torque is removed.

Typical examples include:

• Vertical axes.
• Lifting mechanisms.
• Z-axis machinery.
• Positioning systems.
• Automated equipment with gravity-loaded components.
• Machines requiring mechanical holding during servo shutdown.

The brake should not normally be treated as the primary dynamic stopping device for repeated high-energy deceleration.

The servo drive should normally control the motor’s dynamic deceleration, while the brake provides holding capability when required by the machine sequence.

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14. Brake Advantages

The integrated brake eliminates the need to add a separate motor-mounted holding brake in applications that can use the built-in configuration.

This can simplify:

• Mechanical design.
• Motor selection.
• Brake mounting.
• Cable routing.
• Machine assembly.
• Maintenance.

The brake is especially valuable on vertical axes.

For a vertical axis, the machine control sequence should be designed so that the servo establishes appropriate motor torque before the brake is released.

During shutdown, the servo can normally decelerate the axis before the brake is applied.

The exact control sequence depends on the servo drive, machine control system, load characteristics, and applicable safety requirements.

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15. SpeedTEC DIN Connector

The motor uses a SpeedTEC DIN right-angle connector.

The connector is designed to rotate through approximately 180 degrees.

This provides additional flexibility when installing the motor inside compact machinery.

The connector orientation can be adjusted to accommodate:

• Cable routing.
• Machine guarding.
• Limited cabinet or machine space.
• Adjacent motors.
• Gearboxes.
• Linear guides.
• Mechanical frames.

The right-angle configuration also reduces the space required behind the motor for cable routing compared with some straight connector arrangements.

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16. Dimensions

The current catalog information lists the physical dimensions of the MPL-B320P-MJ74AA as approximately:

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

The motor has a nominal 100 mm frame size and a 50.8 mm magnetic stack length.

Dimension Parameter	Specification
Model	MPL-B320P-MJ74AA
Frame Size	100 mm
Frame Designation	3
Magnetic Stack	50.8 mm
Stack Designation	20
Overall Length	42.799 cm
Overall Width	21.692 cm
Overall Height	26.01 cm
Mounting	IEC metric flange
Shaft	Keyed
Connector	SpeedTEC DIN
Connector Type	Right-angle
Connector Rotation	180°
Approximate Weight	5.509 kg

The listed overall dimensions should be used as a general catalog reference.

For machine fabrication, enclosure design, coupling selection, and replacement work, the exact mechanical drawing should be used to verify shaft projection, mounting-hole locations, flange dimensions, connector clearance, and installation envelope.

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17. Weight

The listed motor weight is approximately 5.509 kg.

Weight Parameter	Value
Model	MPL-B320P-MJ74AA
Motor Weight	5.509 kg
Weight Unit	kg
Approximate Rounded Weight	5.51 kg
Shipping Weight	May be higher
Packaging Weight	Not included in motor mass
Installation Design Weight	Use actual unit for final calculations

The 5.509 kg value is the catalog-listed motor weight.

The shipping weight can be higher because packaging materials and accessories may be included.

For robotic arms, moving axes, overhead mechanisms, and machine structural calculations, the actual motor mass should be included in the complete load calculation.

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18. Rotor Inertia

The MPL-B320P-MJ74AA has a rotor inertia of approximately:

0.000078 kg·m²

or:

7.8 × 10⁻⁵ kg·m²

Rotor inertia is important because it affects the motor’s acceleration and deceleration behavior.

A low-inertia motor can respond quickly to changes in commanded speed.

However, the motor is only one part of the complete inertia calculation.

The reflected load inertia, gearbox, coupling, pulley, screw, belt, and driven machine components all contribute to the total effective inertia seen by the servo motor.

For this reason, servo sizing should consider the complete mechanical system.

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19. Electrical Parameters

Electrical Parameter	Specification
Model	MPL-B320P-MJ74AA
Voltage Class	460 V AC
Supply Class	480 V AC
Rated Current Reference	Approx. 3.2 A RMS
Rated Power	1.5 kW
Rated Speed	5000 RPM
Maximum Speed	5000 RPM
Continuous Torque	3.05 N·m
Peak Torque Reference	Approx. 7.91 N·m
Feedback	Multi-turn high-resolution absolute
Brake Voltage	24 V DC
Brake	Integral
Motor Type	Brushless AC servo
Connector	SpeedTEC DIN
Connector Orientation	Right-angle
Connector Rotation	180°

The 460 V electrical configuration and approximately 3.2 A RMS nominal current are reflected in published motor data for the B320P-MJ74AA configuration.

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20. Mechanical Parameters

Mechanical Parameter	Specification
Model	MPL-B320P-MJ74AA
Frame	100 mm
Stack	50.8 mm
Shaft	Keyed
Shaft Seal	None
Mounting Flange	IEC metric
Mounting Hole Type	Free mounting holes, Type FF
Brake	24 V DC integral
Connector	SpeedTEC DIN
Connector Type	Right-angle
Connector Rotation	180°
Rotor Inertia	0.000078 kg·m²
Overall Length	42.799 cm
Overall Width	21.692 cm
Overall Height	26.01 cm
Weight	5.509 kg

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21. Typical Applications

Packaging Machinery

The MPL-B320P-MJ74AA is suitable for packaging machines requiring rapid, repeatable servo movement.

Typical applications include:

• Film feeding.
• Product indexing.
• Cutting.
• Sealing.
• Label positioning.
• Conveyor synchronization.
• Rotary indexing.

The high-speed 5000 RPM capability supports rapid machine cycles.

The absolute multi-turn encoder provides position feedback for synchronized motion.

The integral brake can be useful where a machine axis needs to remain mechanically held after servo torque is removed.

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Material Handling

Material-handling machinery frequently requires controlled movement between known positions.

The motor can be used in:

• Transfer systems.
• Conveyor positioning.
• Sorting systems.
• Indexing mechanisms.
• Automated loading systems.
• Pick-and-place equipment.

The keyed shaft allows the motor to be mechanically coupled to compatible transmission components.

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Automated Assembly

Automated assembly machinery requires repeatable positioning and coordinated movement.

The MPL-B320P-MJ74AA can be used for:

• Rotary indexing.
• Component positioning.
• Actuator systems.
• Feeding mechanisms.
• Assembly stations.
• Screw-driving mechanisms.
• Automated fixture positioning.

The multi-turn absolute encoder is useful for axes that move through multiple motor revolutions.

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Machine Tools

Servo motors are commonly used for controlled machine-tool movement.

The MPL-B320P-MJ74AA can be considered for appropriate positioning or auxiliary axes where the required speed, torque, feedback, and mechanical interface are compatible.

The keyed shaft is useful where the machine uses conventional keyed mechanical couplings.

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Pick-and-Place Systems

Pick-and-place machinery benefits from fast acceleration and deceleration.

The low-inertia motor design supports rapid changes in motor speed.

The encoder provides the feedback necessary for closed-loop motion control.

The brake can be valuable when an axis has a vertical movement component.

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Printing Machinery

Printing equipment often requires synchronized rotary movement.

Servo motors can control:

• Feed rollers.
• Registration systems.
• Cutting mechanisms.
• Tension-related axes.
• Product positioning.
• Rotary synchronization.

The 5000 RPM rating provides considerable speed capability for such applications.

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Converting Equipment

Converting machinery often requires precise synchronization between feeding, cutting, winding, and positioning operations.

The MPL-B320P-MJ74AA can be applied to suitable rotary axes where its torque, speed, feedback, and mechanical configuration match the machine requirements.

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Textile Machinery

Textile equipment frequently operates with repeated high-speed motion.

Servo-controlled feeding, winding, cutting, indexing, and positioning systems can benefit from the low-inertia construction.

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Inspection and Automation Equipment

Automated inspection machines often require precise movement of workpieces, fixtures, cameras, sensors, or positioning mechanisms.

The motor can be used for rotary indexing or linear movement through an appropriate mechanical transmission.

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22. Main Product Advantages

22.1 High-Speed Operation

The 5000 RPM speed rating allows rapid motor movement.

This is useful for applications where high machine throughput and short cycle times are important.

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22.2 Low-Inertia Construction

The low-inertia rotor supports fast acceleration and deceleration.

This is especially valuable in indexing and repetitive motion applications.

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22.3 Multi-Turn Absolute Feedback

The multi-turn absolute encoder provides position information across multiple motor revolutions.

This makes it useful for long-travel and multi-revolution applications.

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22.4 High-Resolution Feedback

High-resolution feedback supports precise control of speed and position.

This can improve repeatability when the motor is correctly matched to the machine mechanics and control system.

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22.5 Integrated Brake

The 24 V DC brake provides a convenient holding function.

It is especially useful for vertical or gravity-loaded axes.

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22.6 Keyed Shaft

The keyed shaft provides a conventional mechanical interface.

This makes it suitable for compatible couplings, pulleys, and transmission components.

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22.7 Compact 100 mm Frame

The 100 mm frame provides a relatively compact package for the motor’s power class.

This helps machine designers manage limited installation space.

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22.8 Rotatable Right-Angle Connector

The 180° rotatable connector provides additional flexibility when routing cables.

This can simplify installation in compact machinery.

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23. Applications Where the Brake Is Especially Useful

The integral brake makes the MPL-B320P-MJ74AA particularly interesting for applications involving vertical movement.

Examples include:

• Z-axis mechanisms.
• Vertical lifts.
• Pick-and-place vertical axes.
• Elevating platforms.
• Vertical conveyors.
• Gravity-loaded positioning systems.
• Machine-tool vertical axes.

The brake allows the machine to hold the motor shaft mechanically when the servo is not providing active torque.

The exact brake control sequence must be designed as part of the complete machine control and safety system.

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24. Applications Where the No-Brake Version May Be Preferable

For comparison, a no-brake configuration can be useful on horizontal axes where the load does not require mechanical holding.

A no-brake motor can reduce the number of brake-related control requirements.

However, the MPL-B320P-MJ74AA specifically includes the 24 V DC brake, so a machine using this motor should include the appropriate brake wiring and control arrangement.

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25. Installation Considerations

The motor should be installed on a rigid machine structure.

The mounting flange should be properly aligned.

The motor shaft should be aligned with the driven mechanism.

Incorrect alignment can increase:

• Bearing load.
• Coupling stress.
• Vibration.
• Noise.
• Mechanical wear.

The keyed shaft should be used with a compatible coupling or transmission component.

The coupling should be selected according to the actual shaft dimensions and machine requirements.

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26. Cable Routing

The SpeedTEC DIN connector provides useful flexibility, but the motor cable should still be installed carefully.

The cable should be protected from:

• Excessive bending.
• Crushing.
• Abrasion.
• Sharp edges.
• High temperatures.
• Moving mechanisms.
• Excessive tension.
• Repeated mechanical stress.

The 180° connector rotation should be used to establish a practical cable exit direction rather than forcing the cable into an unsuitable bend radius.

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27. Brake Control

The brake requires an appropriate 24 V DC control arrangement.

The machine control system should coordinate brake operation with servo torque.

For a vertical axis, a typical control concept is to establish sufficient motor torque before releasing the brake.

During shutdown, the servo can decelerate the load and the brake can then be applied to hold the stationary axis.

The exact timing should be determined by the machine designer according to the load, drive behavior, mechanical system, and safety requirements.

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28. Servo Tuning

The low-inertia construction makes this motor suitable for fast dynamic response.

However, proper servo tuning depends on the entire machine.

Important factors include:

• Motor inertia.
• Load inertia.
• Reflected inertia.
• Gearbox ratio.
• Coupling stiffness.
• Belt stiffness.
• Screw stiffness.
• Backlash.
• Friction.
• Mechanical resonance.
• Acceleration.
• Deceleration.
• Load disturbance.

The servo system should therefore be tuned after the complete mechanical system is installed.

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29. Maintenance

Because the MPL-B320P-MJ74AA is a brushless servo motor, it does not require traditional brush replacement.

Maintenance should instead focus on the mechanical and electrical system.

Maintenance Item	Inspection
Model	MPL-B320P-MJ74AA
Mounting	Check flange and mounting bolts
Shaft	Inspect shaft and coupling
Keyway	Check key and keyway condition
Bearings	Check temperature, noise, and vibration
Encoder	Check feedback stability
Brake	Check brake release and holding operation
Connector	Inspect connector condition
Cable	Check bending and abrasion
Grounding	Verify proper grounding
Cooling	Maintain adequate heat dissipation
Vibration	Monitor abnormal vibration
Noise	Investigate unusual noise
Mechanical Alignment	Check motor/load alignment

Regular inspection is particularly important for high-cycle machines.

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30. Replacement Considerations

When replacing another servo motor with the MPL-B320P-MJ74AA, the complete configuration should be checked.

Replacement Parameter	MPL-B320P-MJ74AA
Model	MPL-B320P-MJ74AA
Voltage	460 V class
Power	1.5 kW
Speed	5000 RPM
Continuous Torque	3.05 N·m
Peak Torque	Approx. 7.91 N·m
Frame	100 mm
Stack	50.8 mm
Feedback	Multi-turn high-resolution absolute
Shaft	Keyed
Brake	24 V DC
Connector	SpeedTEC DIN
Mounting	IEC metric
Rotor Inertia	0.000078 kg·m²
Dimensions	42.799 × 21.692 × 26.01 cm
Weight	5.509 kg

A replacement should not be selected solely by matching voltage and power.

The feedback system is especially important.

The motor’s multi-turn absolute encoder must be compatible with the intended servo drive and controller.

The keyed shaft must also match the machine’s mechanical coupling.

The brake must be correctly integrated into the machine’s control system.

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31. Five Closely Related Models

The following models are useful comparisons within the same MPL family and B320P platform.

Related Model	Voltage	Frame	Stack	Speed	Feedback	Shaft	Brake	Power	Continuous Torque	Weight
MPL-B320P-MJ72AA	460 V	100 mm	50.8 mm	5000 RPM	Multi-turn high-resolution absolute	Keyed	No	1.5 kW	3.05 N·m	Approx. 4.5 kg
MPL-B320P-MJ74AA	460 V	100 mm	50.8 mm	5000 RPM	Multi-turn high-resolution absolute	Keyed	24 V DC	1.5 kW	3.05 N·m	5.509 kg
MPL-B320P-MK72AA	460 V	100 mm	50.8 mm	5000 RPM	Multi-turn high-resolution absolute	Keyless	No	1.5 kW	3.05 N·m	Verify exact unit
MPL-B320P-MK74AA	460 V	100 mm	50.8 mm	5000 RPM	Multi-turn high-resolution absolute	Keyless	24 V DC	1.5 kW	3.05 N·m	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	3.05 N·m	Verify exact unit

The MPL-B320P-MJ72AA is the closest no-brake counterpart to the MJ74AA.

The MPL-B320P-MK74AA retains the same multi-turn feedback and brake but changes the shaft from keyed to keyless.

The MPL-B320P-HJ74AA retains the keyed shaft and brake but changes the feedback configuration from multi-turn absolute to incremental.

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32. Same-Series Comparison

Model	Feedback	Shaft	Brake	Speed	Frame	Stack	Power	Continuous Torque	Weight
MPL-B320P-MJ72AA	Multi-turn absolute	Keyed	No	5000 RPM	100 mm	50.8 mm	1.5 kW	3.05 N·m	Approx. 4.5 kg
MPL-B320P-MJ74AA	Multi-turn absolute	Keyed	24 V DC	5000 RPM	100 mm	50.8 mm	1.5 kW	3.05 N·m	5.509 kg
MPL-B320P-MK72AA	Multi-turn absolute	Keyless	No	5000 RPM	100 mm	50.8 mm	1.5 kW	3.05 N·m	Verify exact unit
MPL-B320P-MK74AA	Multi-turn absolute	Keyless	24 V DC	5000 RPM	100 mm	50.8 mm	1.5 kW	3.05 N·m	Verify exact unit
MPL-B320P-HJ72AA	Incremental	Keyed	No	5000 RPM	100 mm	50.8 mm	1.5 kW	3.05 N·m	Verify exact unit
MPL-B320P-HJ74AA	Incremental	Keyed	24 V DC	5000 RPM	100 mm	50.8 mm	1.5 kW	3.05 N·m	Verify exact unit

The models in this table use the same general B320P platform, while the principal differences are feedback technology, shaft configuration, and brake arrangement.

This makes the table useful when selecting an alternative configuration for an existing machine.

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33. Five Other Popular Allen-Bradley Servo Motor Models

The following models are useful as broader comparison points within the Allen-Bradley MPL servo motor range.

Model	Series	Voltage	Frame / Class	Speed	Power	Continuous Torque	Feedback	Shaft	Brake	Weight
MPL-B310P-MJ74AA	MPL	460 V	100 mm class	5000 RPM	0.77 kW	1.58 N·m	Multi-turn absolute	Keyed	24 V DC	Verify exact unit
MPL-B320P-HK74AA	MPL	460 V	100 mm	5000 RPM	1.5 kW	3.05 N·m	Incremental	Keyless	24 V DC	Approx. 2.72–4.5 kg depending on configuration reference
MPL-B330P-MK74AA	MPL	460 V	B330P class	5000 RPM	1.8 kW	4.18 N·m	Multi-turn absolute	Keyless	24 V DC	Verify exact unit
MPL-B420P-MJ74AA	MPL	460 V	B420P class	5000 RPM	1.9 kW	4.74 N·m	Multi-turn absolute	Keyed	24 V DC	Verify exact unit
MPL-B430P-MJ72AA	MPL	460 V	B430P class	5000 RPM	Approx. 2.2 kW	Approx. 6.55 N·m	Multi-turn absolute	Keyed	No	Verify exact unit

The B320P, B330P, and B420P configurations illustrate the progression toward higher continuous torque and power within the MPL family. Published motor data lists approximately 3.05 N·m for B320P, 4.18 N·m for B330P, and 4.74 N·m for B420P configurations.

The larger models should not be treated as direct replacements merely because they offer higher torque.

A larger motor can require different mounting arrangements, different mechanical clearances, different cables, and different drive sizing.

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34. Model Comparison for Selection

Model	Main Configuration	Suitable Mechanical Situation
MPL-B320P-MJ74AA	Multi-turn absolute, keyed shaft, brake	Applications requiring absolute feedback and mechanical holding
MPL-B320P-MJ72AA	Multi-turn absolute, keyed shaft, no brake	Horizontal axes without brake requirement
MPL-B320P-MK74AA	Multi-turn absolute, keyless shaft, brake	Applications requiring absolute feedback, brake, and keyless coupling
MPL-B320P-HJ74AA	Incremental, keyed shaft, brake	Applications using compatible incremental feedback and keyed coupling
MPL-B320P-HK74AA	Incremental, keyless shaft, brake	Applications using incremental feedback and keyless coupling

The correct model depends on the actual machine architecture.

The feedback type, shaft type, and brake configuration should be treated as major selection parameters rather than secondary options.

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35. Difference Between MJ74AA and MJ72AA

The MPL-B320P-MJ74AA and MPL-B320P-MJ72AA are extremely similar motor configurations.

Parameter	MPL-B320P-MJ74AA	MPL-B320P-MJ72AA
Voltage	460 V class	460 V class
Frame	100 mm	100 mm
Stack	50.8 mm	50.8 mm
Speed	5000 RPM	5000 RPM
Power	1.5 kW	1.5 kW
Continuous Torque	3.05 N·m	3.05 N·m
Feedback	Multi-turn absolute	Multi-turn absolute
Shaft	Keyed	Keyed
Brake	24 V DC	No brake
Connector	SpeedTEC DIN	SpeedTEC DIN
Rotor Inertia	Approx. 0.000078 kg·m²	Approx. 0.000078 kg·m²
Weight	5.509 kg	Approx. 4.5 kg reference

The primary difference is the integral brake.

The MJ74AA is therefore more appropriate for machine designs that require an integrated holding brake.

The MJ72AA is the corresponding no-brake configuration.

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36. Difference Between MJ74AA and MK74AA

The main difference between these two configurations is the shaft.

Parameter	MPL-B320P-MJ74AA	MPL-B320P-MK74AA
Voltage	460 V class	460 V class
Frame	100 mm	100 mm
Stack	50.8 mm	50.8 mm
Speed	5000 RPM	5000 RPM
Power	1.5 kW	1.5 kW
Feedback	Multi-turn absolute	Multi-turn absolute
Shaft	Keyed	Keyless
Brake	24 V DC	24 V DC
Connector	SpeedTEC DIN	SpeedTEC DIN
Continuous Torque	3.05 N·m	3.05 N·m
Weight	5.509 kg	Verify exact unit

The MJ74AA should therefore be selected when the machine requires the keyed shaft arrangement.

The MK74AA should be considered when the mechanical transmission is designed for a keyless shaft.

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37. Difference Between MJ74AA and HJ74AA

These two models share the keyed shaft and brake arrangement but differ in feedback.

Parameter	MPL-B320P-MJ74AA	MPL-B320P-HJ74AA
Voltage	460 V class	460 V class
Frame	100 mm	100 mm
Stack	50.8 mm	50.8 mm
Speed	5000 RPM	5000 RPM
Power	1.5 kW	1.5 kW
Feedback	Multi-turn absolute	Incremental
Shaft	Keyed	Keyed
Brake	24 V DC	24 V DC
Continuous Torque	3.05 N·m	3.05 N·m
Connector	SpeedTEC DIN	SpeedTEC DIN
Approx. Weight	5.509 kg	Verify exact unit

The feedback difference is electrically significant.

The servo drive and controller must be configured for the correct feedback technology.

A machine designed for the MJ74AA should therefore not automatically use an HJ74AA without checking the drive, controller, feedback interface, and commissioning requirements.

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38. Engineering Advantages

The MPL-B320P-MJ74AA offers a useful combination of:

• High rotational speed.
• Compact frame size.
• Low rotor inertia.
• Absolute multi-turn feedback.
• Keyed shaft.
• Integrated holding brake.
• Flexible connector orientation.
• 1.5 kW power class.
• 3.05 N·m continuous torque.
• Approximately 7.91 N·m peak torque.

This combination makes it suitable for machines that require both dynamic servo performance and mechanical holding capability.

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39. Practical Selection Checklist

Before ordering or installing an MPL-B320P-MJ74AA, verify the following:

Check Item	Requirement
Model	MPL-B320P-MJ74AA
Voltage	460 V class
Power	1.5 kW
Speed	5000 RPM
Continuous Torque	3.05 N·m
Peak Torque	Approx. 7.91 N·m
Frame	100 mm
Stack	50.8 mm
Feedback	Multi-turn high-resolution absolute
Shaft	Keyed
Brake	24 V DC
Connector	SpeedTEC DIN
Mounting	IEC metric
Length	42.799 cm
Width	21.692 cm
Height	26.01 cm
Weight	5.509 kg
Shaft Dimensions	Verify mechanical drawing
Coupling	Verify keyed-shaft compatibility
Drive	Verify feedback and motor compatibility
Cable	Verify connector and cable compatibility

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40. Final Technical Summary

Category	Specification
Model	MPL-B320P-MJ74AA
Brand	Allen-Bradley
Series	MP-Series MPL
Product Type	Low-Inertia Brushless AC Rotary Servo Motor
Voltage Class	460 V AC
Supply Class	480 V AC
Rated Power	1.5 kW
Rated Speed	5000 RPM
Maximum Speed	5000 RPM
Continuous Torque	3.05 N·m
Peak Torque	Approx. 7.91 N·m
Frame Size	100 mm
Frame Designation	3
Magnetic Stack	50.8 mm
Stack Designation	20
Feedback	Multi-turn high-resolution absolute encoder
Shaft	Keyed
Brake	Integral 24 V DC
Connector	SpeedTEC DIN
Connector Type	Right-angle
Connector Rotation	180°
Mounting	IEC metric flange
Mounting Holes	Free mounting holes, Type FF
Shaft Seal	None
Rotor Inertia	Approx. 0.000078 kg·m²
Overall Length	42.799 cm
Overall Width	21.692 cm
Overall Height	26.01 cm
Weight	5.509 kg
Application	Industrial closed-loop motion control

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41. Final Product Description

The Allen-Bradley MPL-B320P-MJ74AA is a high-speed, low-inertia brushless AC servo motor designed for industrial motion-control applications.

It operates in the 460 V-class range and provides approximately 1.5 kW rated power, 3.05 N·m continuous torque, and 5000 RPM rated speed.

The motor uses a 100 mm frame and a 50.8 mm magnetic stack, giving it a compact mechanical format while maintaining useful torque and speed capability.

Its most distinctive feature is the multi-turn high-resolution absolute encoder.

This feedback system provides detailed position information across multiple motor revolutions and is particularly useful in positioning, indexing, automation, machine-tool, packaging, and material-handling applications.

The keyed shaft provides a conventional mechanical interface for compatible couplings and transmission components.

The integral 24 V DC brake provides a useful holding function, particularly for vertical axes and gravity-loaded mechanisms.

The motor also uses a right-angle SpeedTEC DIN connector with 180° rotational flexibility, allowing the connector and motor cable to be positioned more conveniently within the machine.

The listed physical dimensions are approximately 42.799 cm in length, 21.692 cm in width, and 26.01 cm in height, with a catalog weight of approximately 5.509 kg.

The principal specifications can therefore be summarized as 460 V class, 1.5 kW, 5000 RPM, 3.05 N·m continuous torque, approximately 7.91 N·m peak torque, 100 mm frame, 50.8 mm stack, multi-turn high-resolution absolute feedback, keyed shaft, 24 V DC brake, 42.799 × 21.692 × 26.01 cm dimensions, and 5.509 kg weight.

For applications requiring fast and repeatable servo movement together with absolute multi-turn position feedback and an integrated holding brake, the MPL-B320P-MJ74AA represents a comprehensive motor configuration within the MPL low-inertia servo family.

For replacement work, the most important parameters are not only the power and dimensions, but also the feedback type, shaft arrangement, brake configuration, connector type, motor voltage, and drive compatibility.