Allen-Bradley MPL-B320P-SJ24AA Servo Motor

1. Product Overview

The Allen-Bradley MPL-B320P-SJ24AA is a low-inertia permanent-magnet rotary servo motor belonging to the MP-Series servo motor family. It is designed for industrial motion-control systems where accurate positioning, controlled acceleration, high rotational speed, and repeatable servo performance are required.

The MPL-B320P-SJ24AA uses a 100 mm frame and a 50.8 mm magnetic stack length. It is rated for operation in the 460 V class and is capable of reaching a rated maximum speed of 5000 rpm. The motor provides approximately 1.5 kW of rated power and approximately 3.05 N·m of continuous torque, making it suitable for a wide range of machine-axis applications.

A major feature of this particular model is its single-turn high-resolution encoder feedback. This allows the servo drive to continuously monitor motor position and speed, providing the feedback required for closed-loop motion control.

The model also incorporates a 24 V DC holding brake, a keyed shaft, an IEC metric mounting flange, and a right-angle bayonet-style connector. These features make it well suited to machine designs where controlled stopping, mechanical coupling, and flexible cable routing are important.

The model is identified in industrial catalogs as a low-inertia MP-Series permanent-magnet rotary servo motor. The exact model configuration is associated with a 100 mm frame, 2-inch magnetic stack, 5000 rpm speed, single-turn high-resolution encoder, keyed shaft, and 24 V DC brake.

2. Brand and Series

The MPL Series is intended for applications where fast response and accurate servo positioning are more important than the high inertia and simple operating characteristics of a conventional induction motor.

The B320P size represents a compact but relatively powerful motor within the 100 mm frame class. The 50.8 mm magnetic stack provides a useful balance between motor length, torque capability, and dynamic response.

3. Model Number Interpretation

The model number MPL-B320P-SJ24AA contains information describing the motor’s basic construction and options.

The model code is useful when selecting a replacement motor because motors that look physically similar can have substantially different feedback devices, shaft configurations, connector arrangements, or brake options.

For that reason, the complete catalog number should be checked rather than selecting a motor only by frame size or power rating.

4. Detailed Technical Parameters

Main Electrical and Mechanical Specifications

The listed product weight for the exact SJ24AA configuration is approximately 4.08 kg. Some older catalog records list approximately 5.1 kg for this configuration, so the actual shipping/catalog weight can vary depending on the measurement basis and revision. For engineering and replacement work, the physical motor drawing and current product documentation should take precedence over a distributor-listed shipping weight.

Performance Parameters

The combination of 1.5 kW power and 5000 rpm maximum speed makes this motor particularly useful for applications requiring rapid indexing and frequent acceleration and deceleration.

Its low-inertia construction allows the motor to respond quickly to changes in commanded speed and position. This characteristic is especially useful when the machine axis has relatively low reflected load inertia and requires rapid motion correction.

5. Feedback System

The MPL-B320P-SJ24AA uses a single-turn high-resolution encoder for motor feedback.

This is an important distinction between the SJ configuration and resolver-based versions of the B320P motor family.

The encoder provides the servo control system with position information so that the drive can regulate motor speed, position, and torque in a closed-loop arrangement.

For applications such as indexing, electronic gearing, registration, synchronized motion, and precision positioning, the feedback system is a critical part of the complete servo package.

When replacing this motor, the feedback type should therefore be matched with the drive and the existing motor configuration. A motor with a similar frame size but a different feedback technology should not automatically be treated as a direct replacement.

6. Shaft and Mechanical Configuration

The MPL-B320P-SJ24AA uses a keyed shaft.

The shaft key provides a positive mechanical connection between the motor shaft and a compatible coupling, pulley, gear, or other transmission component.

The model is also listed without an integrated shaft seal. This means that the mechanical environment around the shaft should be considered carefully when installing the motor.

The mounting system uses an IEC metric flange, making the motor suitable for machine structures designed around metric servo-motor mounting standards.

The 100 mm frame size provides a relatively compact installation envelope while retaining the torque capacity required for medium-duty servo applications.

7. Brake System

One of the most useful features of the MPL-B320P-SJ24AA is the integrated 24 V DC holding brake.

The brake is primarily intended to hold the motor shaft when the servo system is disabled or when the machine requires the axis to remain stationary.

The brake should not normally be treated as the primary method of dynamic stopping during ordinary servo operation. The servo drive and motor should normally perform controlled deceleration, while the mechanical brake is used for holding or specific stopping functions according to the machine design.

The brake control circuit should also be designed so that the brake releases and engages at the correct points in the servo sequence.

8. Connector Arrangement

The motor uses a circular bayonet-style connector with a right-angle arrangement.

The connector configuration provides additional flexibility when the motor is installed in a compact machine.

The right-angle design is particularly useful when straight cable exits would interfere with machine guards, structural members, or adjacent equipment.

The connector can be rotated within its specified range, allowing the cable direction to be adjusted during installation.

Proper connector engagement is important because servo motors depend on reliable power and feedback connections. A loose motor connector can result in intermittent encoder feedback, drive faults, following errors, or unexpected motor shutdown.

9. Product Introduction

The MPL-B320P-SJ24AA can be considered a compact industrial servo motor designed for applications where the machine requires controlled rotary motion rather than simple continuous-speed operation.

A conventional motor may provide rotational power, but a servo motor is designed to work together with a servo drive and feedback device to control the movement of the machine axis.

The B320P motor provides a useful combination of speed, torque, compact dimensions, and low rotor inertia.

The 5000 rpm speed capability is especially useful for high-cycle machines where the motor needs to accelerate quickly, move through a positioning cycle, decelerate, and repeat the process many times.

The integrated single-turn encoder provides the feedback necessary for closed-loop positioning and speed control.

10. Main Advantages

10.1 High-Speed Operation

The 5000 rpm speed rating allows the motor to operate at high rotational speed.

This can be valuable in packaging, indexing, converting, printing, and other equipment where short cycle times are important.

10.2 Low-Inertia Construction

The low-inertia rotor design allows the motor to respond rapidly to changes in command.

Lower rotor inertia can reduce the amount of energy required to accelerate the motor itself and can help the servo system achieve fast dynamic response when the mechanical load is appropriately matched.

10.3 High-Resolution Feedback

The single-turn high-resolution encoder provides detailed position feedback to the servo controller.

This is important for applications that require repeatable positioning, controlled velocity, and accurate synchronization.

10.4 Integrated Holding Brake

The 24 V DC brake provides a convenient way to hold the motor shaft when the servo system is not actively controlling the axis.

This can be useful on vertical or mechanically sensitive axes where unintended movement must be prevented while the machine is stopped.

10.5 Compact 100 mm Frame

The 100 mm frame provides a relatively compact motor package for its performance class.

This is useful where the machine designer has limited cabinet, guarding, or mechanical installation space.

10.6 Keyed Shaft

The keyed shaft provides a familiar mechanical connection method for couplings, gears, pulleys, and other mechanical transmission components.

It is particularly convenient when the machine uses conventional keyed mechanical components.

10.7 Flexible Connector Orientation

The right-angle connector arrangement and rotatable connector design make cable routing easier in compact machine installations.

This can reduce the possibility of cable interference with surrounding mechanical components.

10.8 IEC Metric Mounting

The IEC metric flange provides compatibility with machine structures designed around metric mechanical dimensions.

This is particularly useful in international machine-building environments.

11. Typical Applications

Packaging Machinery

The MPL-B320P-SJ24AA can be used for packaging-machine axes that require rapid indexing, synchronized movement, and repeated acceleration and deceleration.

Typical applications can include feed mechanisms, indexing units, sealing mechanisms, cutting axes, product positioning, and material-handling sections.

The high-speed capability and encoder feedback are useful when the machine must maintain repeatable product registration.

Automated Assembly Equipment

Automated assembly machines frequently require several servo axes working together.

The B320P motor can be applied to positioning mechanisms, transfer systems, rotary indexing tables, pick-and-place mechanisms, and controlled assembly stations.

Material Handling

Servo motors are often used in material-handling systems when accurate movement is required rather than simple conveyor rotation.

The motor can be applied to indexing conveyors, transfer mechanisms, positioning tables, lift mechanisms, and synchronized transport systems, provided the load and braking requirements are correctly calculated.

Printing and Converting Equipment

Printing and converting machines require accurate speed and position coordination.

A high-speed servo motor with encoder feedback can be used for web handling, registration, indexing, roller positioning, cutting, and other controlled rotary axes.

Labeling Machines

Labeling equipment commonly requires high repeatability and accurate synchronization between product movement and labeling mechanisms.

The B320P’s encoder feedback and high-speed capability make this type of servo motor suitable for positioning and synchronization duties.

Machine Tools and Auxiliary Axes

The motor can also be considered for machine-tool auxiliary axes, indexing mechanisms, tool-handling systems, and other controlled rotary movements.

Actual suitability depends on the required torque curve, duty cycle, acceleration, mechanical transmission, and servo-drive compatibility.

Electronics Manufacturing Equipment

Electronics production equipment frequently uses servo motors for precise indexing and controlled positioning.

Applications can include component handling, assembly indexing, inspection mechanisms, feeder systems, and automated transfer units.

Inspection and Test Machines

Inspection systems often require controlled movement of cameras, sensors, fixtures, rotary tables, or test components.

The encoder feedback provides the position information necessary for repeatable axis movement.

12. Application Characteristics

13. Important Installation Considerations

Before installing the MPL-B320P-SJ24AA, the motor should be matched with the appropriate servo drive.

The feedback interface is especially important. Because this motor uses a single-turn high-resolution encoder, the drive and feedback wiring must support the corresponding encoder technology.

The mechanical mounting dimensions should also be verified before replacement. A motor with the same general frame size does not necessarily have the same shaft, connector, mounting, or feedback configuration.

The coupling should be correctly aligned with the motor shaft. Excessive radial or axial loading can reduce bearing life and may produce abnormal vibration.

The motor should not be lifted by the shaft.

The power cable and feedback cable should be routed so that they are protected from excessive bending, mechanical abrasion, heat, and interference.

The 24 V DC brake circuit should also be correctly integrated into the machine safety and servo-control sequence.

14. Maintenance Considerations

Regular inspection of the motor installation can help identify problems before they become major equipment failures.

The following items are worth monitoring:

• Motor temperature
• Abnormal vibration
• Unusual bearing noise
• Coupling alignment
• Shaft and coupling condition
• Brake operation
• Encoder feedback stability
• Connector condition
• Cable condition
• Servo following error
• Repeated drive faults
• Mechanical backlash
• Mounting-bolt condition

A servo motor that begins producing abnormal vibration or repeated encoder-related faults should not simply be replaced without checking the complete mechanical and electrical system.

15. Five Closely Related Models

The following models are useful comparison points within the same B320P/MPL family. They differ mainly in feedback, shaft, brake, or connector configuration.

The B320P models are closely related mechanically because they share the same basic motor frame and magnetic-stack class.

The major differences are in feedback technology, shaft configuration, and brake configuration.

The SJ24AA is therefore particularly useful when a machine requires a keyed shaft, single-turn high-resolution feedback, and an integrated 24 V DC brake.

16. Comparison of the Five Related Models

The table shows why model numbers should be checked carefully before ordering.

For example, SJ24AA and SJ22AA are very similar model numbers, but the brake configuration is different. Likewise, changing the first feedback letter from S to R or M changes the feedback technology.

17. Five Representative Same-Brand Models

The following five models are representative motors from the same brand and MPL family that are commonly useful for comparison when selecting servo motors of different capacity levels.

These models demonstrate the progression within the MPL motor family.

The B310P is a lower-power option, while the B320P occupies the middle of the compact 100 mm frame range. The B330P provides additional torque, while the B420P and B430P move toward higher-output applications.

18. Detailed Same-Brand Model Parameters

MPL-B310P-MJ24AA

The MPL-B310P-MJ24AA is a smaller motor within the same general MPL family. It is rated around 0.77 kW and approximately 1.58 N·m continuous torque, with a 5000 rpm speed class.

This model can be considered when the machine load is lower than the B320P requirement.

MPL-B320P-MK24AA

The MPL-B320P-MK24AA has the same general B320P performance class as the SJ24AA but uses a different feedback and shaft configuration.

It can be useful where multi-turn feedback and a keyless shaft are preferred.

MPL-B330P-MJ24AA

The MPL-B330P-MJ24AA increases the torque capability compared with the B320P.

This motor can be considered when the B320P torque level is not sufficient but the machine still requires a 5000 rpm servo motor.

MPL-B420P-MJ24AA

The MPL-B420P-MJ24AA is a higher-capacity motor in the same general MPL family.

Its higher torque capability makes it suitable for machine axes requiring more mechanical output than the B320P.

MPL-B430P-MJ24AA

The MPL-B430P-MJ24AA represents another step upward in output capability.

This model is more appropriate for higher-load applications where the B320P torque level would not provide enough continuous capacity.

19. B320P Family Performance Comparison

The B320P is an important middle point in this group because it provides substantially more torque than the B310P while remaining smaller and lighter than the higher-capacity B420P and B430P configurations.

20. Selection Considerations

When selecting the MPL-B320P-SJ24AA for a machine, several factors should be evaluated together rather than choosing the motor based only on horsepower.

The first consideration is continuous torque.

The motor must be able to provide the required continuous torque without exceeding its thermal limits during the machine’s actual duty cycle.

The second consideration is peak torque.

Acceleration, deceleration, rapid indexing, and sudden load changes can require substantially more torque than the continuous operating point.

The third consideration is rotor inertia and load inertia.

Servo performance depends strongly on the relationship between motor inertia and reflected load inertia.

The fourth consideration is feedback compatibility.

The SJ24AA uses a single-turn high-resolution encoder. The drive and feedback interface must therefore be compatible with this encoder configuration.

The fifth consideration is mechanical shaft configuration.

Because this model uses a keyed shaft, the machine coupling should be selected accordingly.

The sixth consideration is the holding brake.

The integrated 24 V DC brake can be useful for holding an axis when the servo is disabled, but the machine designer should determine whether additional mechanical braking or safety measures are required.

21. Overall Product Advantages

22. Final Product Summary

The Allen-Bradley MPL-B320P-SJ24AA is a 1.5 kW-class, 5000 rpm low-inertia permanent-magnet rotary servo motor designed for closed-loop industrial motion control.

Its combination of a 100 mm frame, 50.8 mm magnetic stack, approximately 3.05 N·m continuous torque, high-resolution single-turn encoder, keyed shaft, and 24 V DC holding brake makes it a practical configuration for many automated machine axes.

The model is particularly appropriate for applications that need rapid acceleration, repeatable positioning, high-speed operation, and reliable feedback.

Its use should always be evaluated as part of a complete servo system. The motor, drive, encoder interface, brake circuit, mechanical transmission, load inertia, acceleration profile, and duty cycle all influence the final machine performance.

For replacement work, the complete MPL-B320P-SJ24AA catalog number should be matched rather than relying only on the 100 mm frame size or 1.5 kW rating. The feedback type, shaft configuration, brake, connector arrangement, and mounting dimensions are all important parts of the motor configuration.