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Allen-Bradley MPL-B640F-SJ72AA Servo Motor – Detailed Product Specifications, Introduction, Applications, Advantages and Related Models

The Allen-Bradley MPL-B640F-SJ72AA is a low-inertia AC rotary servo motor designed for industrial automation systems that require accurate motion control, fast acceleration and deceleration, stable speed regulation, and repeatable positioning.

It belongs to the MP-Series MPL low-inertia brushless servo motor family and is configured as a 460 V class, 215 mm frame, 101.6 mm magnet-stack, 3000 rpm servo motor with a single-turn high-resolution absolute encoder, keyed shaft, SpeedTEC DIN connector, and no integral brake.

The model is particularly well suited to machinery where the motor must respond quickly to changing motion commands while providing enough continuous and peak torque for demanding mechanical loads.

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1. Product Basic Information

The most important configuration characteristics are therefore 460 V class, 215 mm frame, 101.6 mm stack, 3000 rpm, single-turn absolute feedback, keyed shaft, and no brake.

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2. Product Introduction

The MPL-B640F-SJ72AA is designed for industrial motion applications where ordinary continuous-duty motor operation is not enough.

A servo motor is normally used as part of a closed-loop motion system. The motor works together with a servo drive and motion controller, while the encoder continuously provides feedback about the motor shaft.

This arrangement allows the machine to control position, speed, acceleration, deceleration, and torque much more precisely than a conventional motor system.

The MPL-B640F-SJ72AA uses a low-inertia rotor design, making it particularly suitable for machinery that performs repeated starts, stops, indexing movements, direction changes, and rapid positioning.

Its approximately 36.7 N·m continuous torque gives it substantial continuous output capability, while the approximately 72.3 N·m peak torque rating provides additional torque during acceleration and other short-duration dynamic conditions.

Another important characteristic is its single-turn high-resolution absolute encoder.

This feedback arrangement gives the servo system detailed information about shaft position within one revolution, allowing the motor to be controlled accurately during high-speed and precision motion.

The motor also uses a keyed shaft, which makes it convenient for conventional industrial mechanical transmission systems such as couplings, pulleys, gears, rollers, and other keyed components.

Unlike brake-equipped versions of the same general motor family, the MPL-B640F-SJ72AA has no integral brake.

This makes the motor a practical choice for applications where a holding brake is not required, especially many horizontal-axis applications.

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3. Brand and Product Series

Brand

Allen-Bradley

Product Series

MP-Series MPL

Product Family

MPL Low-Inertia Brushless Servo Motors

The MPL family is intended for industrial servo applications requiring a combination of:

• High dynamic response
• Low rotor inertia
• Accurate feedback
• High torque density
• Reliable speed control
• Precise positioning
• Repetitive motion
• Industrial mechanical compatibility

The MPL-B640F-SJ72AA is one particular configuration within this family.

Its configuration can be summarized as:

MPL + 460 V class + 215 mm frame + 101.6 mm stack + 3000 rpm + single-turn absolute encoder + keyed shaft + no brake.

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4. Detailed Technical Specifications

The dimensions shown above are the principal frame and magnet-stack dimensions. The actual overall installed envelope also depends on the shaft extension, connector orientation, mounting arrangement, and other mechanical details.

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5. Understanding the Model Number

The model number contains useful information about the motor configuration.

The most important distinction is the S in the model number.

The S configuration indicates a single-turn high-resolution encoder.

This is different from the closely related M configuration, which represents a multi-turn feedback arrangement.

The 2 in the later part of the model designation identifies the no-brake configuration.

Therefore, the overall configuration can be remembered as:

MPL-B640F-SJ72AA = 3000 rpm + single-turn absolute feedback + keyed shaft + no brake.

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6. Motor Dimensions

The motor uses a 215 mm frame and 101.6 mm magnet stack.

These are the two most useful dimensional references when identifying the basic motor configuration.

For replacement work, the 215 mm frame should not be treated as the only dimensional requirement.

The actual machine installation should also allow for:

• Shaft extension
• Keyway
• Flange
• Mounting bolts
• Connector body
• Cable bend radius
• Cable clearance
• Mechanical coupling
• Cooling and ventilation space

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7. Motor Weight

The typical listed motor weight is approximately 30.9 kg.

The actual shipping or packaged weight can be higher because packaging, cables, accessories, and protective materials are not necessarily included in the motor-only figure.

The approximately 30.9 kg motor weight should therefore be considered when designing:

• Motor mounting plates
• Machine frames
• Robotic structures
• Vertical installation brackets
• Maintenance access
• Lifting arrangements

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8. Torque Characteristics

The MPL-B640F-SJ72AA provides approximately 36.7 N·m continuous torque and 72.3 N·m peak torque.

The continuous torque rating is important for the normal operating condition.

The peak torque rating becomes important when the machine accelerates, decelerates, changes direction, or encounters short-duration load increases.

For example, consider a rotary indexing machine.

During the indexing period, the motor may need to accelerate the mechanism quickly.

Once the target position is reached, the torque requirement may drop considerably.

The servo motor therefore needs a combination of continuous and peak torque capability rather than simply a large continuous rating.

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9. Low-Inertia Design

The MPL family is built around a low-inertia servo motor concept.

The rotor inertia is approximately 0.004 kg·m², which is relatively low for a motor in this torque class.

Low rotor inertia has a major advantage in dynamic applications.

When the servo drive commands the motor to accelerate, some of the available torque is used to accelerate the motor rotor itself.

A lower rotor inertia means less torque is required for the motor’s own acceleration.

This leaves more available torque for accelerating the external machine load.

The practical result can be:

• Faster acceleration
• Faster deceleration
• Shorter positioning time
• Faster direction changes
• Improved response
• Better suitability for indexing applications
• Higher machine cycle rates

Of course, actual machine performance also depends heavily on load inertia, transmission ratio, mechanical rigidity, and servo tuning.

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10. Single-Turn Absolute Encoder

The MPL-B640F-SJ72AA uses a single-turn high-resolution absolute encoder.

This is one of the defining characteristics of the model.

The encoder provides detailed position information within one revolution.

This feedback information is used by the servo drive to regulate the motor.

It allows the control system to determine the shaft position and compare the actual position against the commanded position.

That difference can then be used to correct the motor’s torque and speed.

This is the fundamental operating principle behind accurate servo positioning.

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11. Single-Turn Feedback Applications

Single-turn absolute feedback is well suited to many industrial applications.

Typical examples include:

• Rotary indexing
• Packaging machines
• Assembly machines
• Conveyor positioning
• Rotary tables
• Machine-tool auxiliary axes
• Material feeding
• Cutting systems
• Pick-and-place mechanisms
• Automated inspection systems

A single-turn encoder is particularly practical when the machine’s positioning requirements can be managed within the control system’s reference strategy.

For applications that specifically require absolute position tracking across multiple motor revolutions, a multi-turn configuration may be more appropriate.

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12. Keyed Shaft Configuration

The motor has a keyed shaft extension.

This is a conventional and widely used industrial shaft arrangement.

A keyed shaft can be connected to:

• Gearboxes
• Couplings
• Pulleys
• Rollers
• Sprockets
• Timing systems
• Mechanical indexing units
• Belt-drive systems

The key provides positive rotational engagement between the shaft and the mechanical component.

For servo applications, the mechanical connection must be properly aligned.

Even a high-quality servo motor can experience positioning problems if the mechanical system contains:

• Excessive backlash
• Loose couplings
• Shaft misalignment
• Flexible mounting
• Worn bearings
• Loose pulleys
• Poorly fitted keys

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13. No-Brake Configuration

The MPL-B640F-SJ72AA has no integral brake.

This is an important difference between this model and brake-equipped versions of the same general motor family.

The no-brake configuration can be advantageous when the motor is driving a horizontal mechanical axis and there is no requirement for mechanical holding after servo torque is removed.

Typical applications include:

• Horizontal conveyors
• Rotary tables
• Roll drives
• Horizontal positioning axes
• Packaging mechanisms
• Feeding systems
• Printing rollers

A no-brake configuration can also simplify electrical integration because there is no motor-mounted brake that requires separate brake control.

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14. When a Brake May Be Required

The absence of a brake should be considered carefully when the motor is used on a vertical axis.

For example, if the motor drives a vertical ballscrew carrying a heavy load, gravity may cause the load to move when the servo motor is no longer producing torque.

In such applications, a brake-equipped configuration may be more appropriate.

A brake can provide mechanical holding, but it should not automatically be considered a complete machine-safety solution.

The complete system may also require:

• Mechanical safety devices
• Proper servo control
• Safety-rated control circuits
• Appropriate stopping functions
• Load-support mechanisms
• Proper brake control

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15. SpeedTEC DIN Connector

The motor uses a right-angle SpeedTEC DIN connector.

The connector is approximately 180° rotatable.

This provides useful flexibility during machine installation.

The connector can be positioned to help avoid interference with:

• Machine frames
• Gearboxes
• Covers
• Cable trays
• Linear guides
• Other motors
• Safety guards

Good cable routing is especially important in servo applications because repeated machine movement can cause mechanical stress on cables and connectors.

The cable should be routed with sufficient bending radius and protected from excessive tension, crushing, abrasion, heat, and moving mechanical parts.

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16. Main Product Applications

16.1 Packaging Machinery

Packaging equipment is one of the most suitable application areas for this type of servo motor.

Packaging machines often require rapid and repetitive motion.

The MPL-B640F-SJ72AA can be considered for:

• Film feeding
• Product indexing
• Cutting mechanisms
• Sealing mechanisms
• Labeling
• Cartoning
• Rotary positioning
• Conveyor synchronization
• Material feeding

The low-inertia design can help the motor respond quickly to repeated motion commands.

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16.2 Automated Assembly Machinery

Assembly equipment often requires precise movement between predefined positions.

The motor can be applied to:

• Rotary indexing stations
• Part feeders
• Component positioning
• Automated insertion
• Transfer mechanisms
• Inspection stations
• Pick-and-place systems

The high-resolution encoder provides the feedback needed for accurate servo positioning.

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16.3 Material Handling

The motor can also be used in material-handling systems.

Potential applications include:

• Conveyor positioning
• Roller drives
• Transfer mechanisms
• Pallet positioning
• Product indexing
• Automated storage machinery
• Material-feeding systems

The motor’s relatively high continuous torque is useful when the driven mechanism has significant mechanical resistance or inertia.

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16.4 Machine Tools

Machine tools use servo motors extensively for controlled positioning.

The MPL-B640F-SJ72AA can be considered for:

• Feed mechanisms
• Positioning axes
• Rotary mechanisms
• Automated tool movement
• Material positioning
• Auxiliary motion axes

The 3000 rpm speed class provides a practical balance between torque and rotational speed for many machine configurations.

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16.5 Printing and Converting Machinery

Printing and converting equipment frequently requires synchronized movement between multiple axes.

Typical applications include:

• Feed rollers
• Registration systems
• Web handling
• Cutting
• Indexing
• Material positioning
• Roller synchronization

The servo motor’s high-resolution feedback and low-inertia characteristics can be useful when the machine needs rapid and repeatable speed changes.

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16.6 Rotary Indexing Systems

Rotary indexing systems are another natural application.

A typical motion sequence may be:

Accelerate → Move → Decelerate → Stop → Process → Repeat

The motor needs sufficient peak torque for acceleration while maintaining accurate position at the end of the motion.

The MPL-B640F-SJ72AA is well suited to this type of repetitive motion when the mechanical load is correctly matched.

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17. Product Advantages

17.1 Strong Continuous Torque

Approximately 36.7 N·m continuous torque gives the motor substantial output capability.

This makes it suitable for industrial machinery requiring more torque than smaller servo motors can comfortably provide.

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17.2 High Peak Torque

Approximately 72.3 N·m peak torque provides additional acceleration capability.

This is particularly useful for:

• Indexing
• Rapid positioning
• Frequent starts and stops
• Direction changes
• High-cycle machinery

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17.3 Low Rotor Inertia

The low-inertia construction is one of the main advantages of the MPL family.

It allows the servo system to respond quickly to changes in command.

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17.4 High-Resolution Absolute Feedback

The single-turn absolute encoder provides detailed position information.

This supports:

• Position control
• Speed control
• Synchronization
• Indexing
• Repeatable motion

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17.5 Keyed Shaft

The keyed shaft provides a conventional mechanical interface.

It is particularly useful for existing machinery that already uses keyed mechanical components.

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17.6 No-Brake Simplicity

When a holding brake is not required, the no-brake configuration simplifies the motor arrangement.

This can be beneficial for horizontal motion axes.

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17.7 Flexible Connector Orientation

The rotatable right-angle connector makes installation easier in crowded machine environments.

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18. Five Closely Related MPL Models

The following models are useful comparison choices within the same general MPL family.

The four B640F configurations are particularly useful when the basic motor size is already established and only feedback or brake requirements need to change.

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19. Detailed B640F Comparison

This comparison shows why the MPL-B640F-SJ72AA is a relatively straightforward configuration.

It provides the same basic B640F mechanical and torque platform while using single-turn feedback and omitting the brake.

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20. Five Commonly Compared Models from the Same Brand

The following models are useful comparison choices when evaluating the MPL-B640F-SJ72AA against other servo-motor configurations from the same brand family.

These models are useful for comparison when selecting between different speed, feedback, shaft, brake, and mechanical configurations.

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21. B580J and B640F Comparison

The B580J and B640F configurations have quite different mechanical designs.

The B580J configuration may be attractive when higher rotational speed is a major requirement.

The B640F configuration is more attractive when the machine needs a larger frame and strong continuous torque with a relatively short magnet stack.

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22. Applications by Machine Type

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23. Why This Motor Is Suitable for Packaging Machinery

Packaging machines often have demanding motion profiles.

A typical machine may need to move a product into position, stop, perform an operation, and then move again.

The motor may therefore experience hundreds or thousands of acceleration and deceleration events during normal operation.

The MPL-B640F-SJ72AA is well suited to this kind of motion because:

• It has low rotor inertia.
• It provides substantial continuous torque.
• It provides higher peak torque for acceleration.
• It has high-resolution feedback.
• It supports accurate closed-loop positioning.
• It uses a conventional keyed shaft.
• It is available in a 3000 rpm configuration.

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24. Why the No-Brake Version Can Be Useful

A common misconception is that a servo motor should always have a brake.

That is not the case.

A brake is primarily useful when the machine requires mechanical holding.

For many horizontal applications, the mechanical load does not naturally fall when the servo is disabled.

Examples include:

• Horizontal conveyors
• Rotary rollers
• Horizontal positioning stages
• Feed mechanisms
• Rotary indexing systems

In these cases, a no-brake motor can be a practical solution.

The simpler configuration can reduce unnecessary components while still providing the full servo-control capability.

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25. Why the Keyed Shaft Is Useful

A keyed shaft is particularly useful in industrial environments where existing mechanical components already use conventional keyed connections.

For example, a motor may be connected to a gearbox.

The gearbox input shaft may use a keyway.

A keyed servo motor can therefore integrate naturally into this type of mechanical architecture.

Other common applications include:

• Belt drives
• Roller drives
• Gear drives
• Pulley systems
• Mechanical indexing
• Conveyor drives

The mechanical connection must still be properly designed to avoid backlash and excessive shaft loading.

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26. Servo System Structure

A typical motion-control system using the MPL-B640F-SJ72AA can be organized as follows:

The motor is only one part of the complete motion system.

Servo performance depends on the relationship between the motor, drive, controller, feedback, mechanical transmission, and load.

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27. Mechanical Load Considerations

Before selecting the motor, the machine’s mechanical load should be evaluated.

Important factors include:

• Load inertia
• Motor inertia
• Gear ratio
• Acceleration
• Deceleration
• Required cycle time
• Continuous torque
• Peak torque
• Mechanical efficiency
• Backlash
• Coupling rigidity
• Radial load
• Axial load

A motor can have a high torque rating but still perform poorly if the mechanical load is badly matched.

For example, a large load inertia combined with a high acceleration requirement can demand substantial peak torque.

The servo drive must also be capable of supplying the required current.

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28. Installation Recommendations

Before installation, check the following areas.

Electrical Installation

Confirm:

• Motor voltage
• Servo drive compatibility
• Feedback compatibility
• Encoder configuration
• Motor cable
• Connector type
• Grounding
• Shielding

Mechanical Installation

Confirm:

• 215 mm frame
• Mounting-hole pattern
• Flange dimensions
• Shaft dimensions
• Keyway
• Coupling
• Mechanical alignment
• Radial load
• Axial load

Cable Installation

Ensure that:

• Cables are not sharply bent.
• Connectors are not under mechanical tension.
• Moving cables have sufficient flexibility.
• Power and signal wiring are properly arranged.
• Cables are protected from abrasion.
• Connector orientation does not interfere with machine components.

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29. Maintenance Recommendations

The motor itself is designed for industrial servo applications, but the surrounding mechanical system should be inspected regularly.

If the motor develops unexpected vibration, the cause may not necessarily be the motor itself.

Possible causes include:

• Loose coupling
• Gearbox backlash
• Bearing wear
• Misalignment
• Poor mounting
• Mechanical resonance
• Incorrect servo tuning

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30. Product Advantages at a Glance

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31. Model Selection Guide

For a horizontal machine axis where single-turn feedback is sufficient and no holding brake is required, the MPL-B640F-SJ72AA is a particularly logical configuration.

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32. Important Replacement Considerations

When replacing an existing motor with an MPL-B640F-SJ72AA, the complete motor configuration should be checked.

Do not select a replacement solely because the frame size appears similar.

The following parameters are particularly important:

The feedback configuration deserves particular attention.

A single-turn model should not automatically be considered interchangeable with a multi-turn model without checking the control system and machine requirements.

The same applies to brake-equipped and no-brake configurations.

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33. Practical Strengths in Industrial Machinery

The main strength of the MPL-B640F-SJ72AA is the balance between torque, speed, feedback resolution, and dynamic response.

It is not simply a motor designed to rotate continuously.

It is designed to participate in a closed-loop motion system.

The low-inertia rotor helps the machine accelerate quickly.

The high-resolution encoder provides position information.

The continuous torque supports the normal mechanical load.

The peak torque provides additional capability during acceleration.

The keyed shaft makes mechanical integration straightforward.

The no-brake configuration keeps the motor relatively simple when mechanical holding is not required.

This combination makes the motor particularly useful for automated machinery with repetitive motion.

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34. Overall Product Summary

The Allen-Bradley MPL-B640F-SJ72AA is a low-inertia AC rotary servo motor belonging to the MP-Series MPL servo motor family.

Its principal configuration is:

460 V class

215 mm frame

101.6 mm magnet stack

3000 rpm

36.7 N·m continuous torque

72.3 N·m peak torque

Single-turn high-resolution absolute encoder

1024 Sin/Cos feedback

Keyed shaft

SpeedTEC DIN connector

No integral brake

Approximately 30.9 kg

The motor is especially suitable for industrial automation applications requiring fast and repeatable motion without the need for an integrated holding brake.

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35. Final Assessment

The MPL-B640F-SJ72AA is a strong choice for industrial servo applications where the machine requires high dynamic response, substantial torque, accurate single-turn absolute feedback, a keyed mechanical interface, and a simple no-brake configuration.

Its low-inertia construction makes it well suited to rapid acceleration and deceleration.

Its approximately 36.7 N·m continuous torque provides substantial output for demanding industrial loads.

Its approximately 72.3 N·m peak torque gives the servo system additional capacity during short-duration acceleration and transient load conditions.

The single-turn high-resolution absolute encoder provides accurate shaft-position feedback and is suitable for many precision positioning applications.

The keyed shaft makes the motor easy to integrate with conventional mechanical transmission systems.

The no-brake configuration makes it particularly attractive for horizontal axes and other applications where mechanical holding is not required.

Its 215 mm frame and 101.6 mm magnet stack provide a useful high-performance configuration without using an excessively long motor body.

For packaging machinery, automated assembly equipment, indexing systems, material handling, conveyors, printing and converting equipment, machine-tool axes, and general industrial automation, the MPL-B640F-SJ72AA is a practical servo-motor configuration.

The easiest way to distinguish this model from its closest relatives is:

MPL-B640F-SJ72AA = Single-turn + Keyed Shaft + No Brake

MPL-B640F-MJ72AA = Multi-turn + Keyed Shaft + No Brake

MPL-B640F-SJ74AA = Single-turn + Keyed Shaft + 24 V DC Brake

MPL-B640F-MJ74AA = Multi-turn + Keyed Shaft + 24 V DC Brake

For a machine that requires a 3000 rpm, 215 mm-frame low-inertia servo motor with single-turn high-resolution absolute feedback but does not require an integral brake, the MPL-B640F-SJ72AA is a well-balanced configuration.