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Allen-Bradley MPL-B4540F-MJ74AA Servo Motor – Complete Technical Specifications, Applications, Advantages and Related Models

1. Product Overview

The Allen-Bradley MPL-B4540F-MJ74AA is a low-inertia brushless AC rotary servo motor designed for industrial motion-control applications that require accurate positioning, high repeatability, fast acceleration and deceleration, and stable servo performance.

It belongs to the MP-Series MPL low-inertia servo motor family and uses a 130 mm frame with a 101.6 mm magnetic stack.

The motor is rated for 3000 rpm and provides approximately 10.2 N·m of continuous stall torque and approximately 27.1 N·m of peak torque. The rated motor output is approximately 2.6 kW.

The MJ74AA configuration combines a multi-turn high-resolution absolute encoder with a keyed shaft and an integral 24 V DC holding brake. It also uses a right-angle SpeedTEC DIN connector that can be rotated approximately 180 degrees.

This combination makes the MPL-B4540F-MJ74AA particularly suitable for industrial machines where accurate multi-turn position feedback and mechanical holding capability are both required.

The motor is especially useful for packaging equipment, automated assembly systems, indexing machinery, material-handling equipment, printing and converting machines, machine tools, inspection systems, and other automated production equipment.

The low-inertia construction allows the motor to respond rapidly to changes in speed and position commands. This is important in applications where short cycle times, rapid indexing, and repeatable positioning are required.

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2. Brand and Product Series

Item	Specification
Brand	Allen-Bradley
Product Family	MP-Series
Product Series	MPL Low-Inertia Servo Motors
Model	MPL-B4540F-MJ74AA
Product Type	AC Rotary Servo Motor
Motor Construction	Brushless Permanent-Magnet Servo Motor
Application	Industrial Motion Control
Voltage Class	460 V AC
Frame Size	130 mm
Frame Classification	Frame 45
Magnet Stack	101.6 mm
Stack Classification	40
Rated Speed	3000 rpm
Maximum Speed	3000 rpm
Continuous Stall Torque	Approx. 10.2 N·m
Peak Torque	Approx. 27.1 N·m
Rated Output	Approx. 2.6 kW
Feedback	Multi-turn high-resolution absolute encoder
Shaft	Keyed shaft extension
Brake	Integral 24 V DC brake
Connector	SpeedTEC DIN
Connector Configuration	Right-angle
Connector Rotation	Approximately 180°
Mounting	IEC metric flange
Mounting Holes	Free mounting holes, Type FF
Rotor Inertia	Approx. 0.00052 kg·m²
Approx. Motor Weight	Approx. 10.6 kg
Typical Operating Temperature	0 to 40 °C

The model designation itself provides useful information about the motor configuration.

The B4540F portion identifies the general motor platform, including the 130 mm frame and 101.6 mm magnetic-stack class.

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

The J identifies the keyed shaft arrangement.

The 7 identifies the SpeedTEC DIN right-angle connector configuration.

The 4 identifies the integral 24 V DC brake option.

The final AA identifies the specific catalog configuration.

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3. Detailed Technical Parameters

Electrical and Performance Specifications

Parameter	Specification
Model	MPL-B4540F-MJ74AA
Brand	Allen-Bradley
Series	MPL Low-Inertia
Product Family	MP-Series
Motor Type	Brushless Permanent-Magnet AC Servo Motor
Voltage Class	460 V AC
Rated Voltage Class	400/460 V class
Rated Speed	3000 rpm
Maximum Speed	3000 rpm
Continuous Stall Torque	Approx. 10.2 N·m
Peak Torque	Approx. 27.1 N·m
Rated Motor Power	Approx. 2.6 kW
Rotor Inertia	Approx. 0.00052 kg·m²
Feedback Type	Multi-turn high-resolution absolute encoder
Shaft Type	Keyed
Brake	Integral 24 V DC brake
Connector	SpeedTEC DIN
Connector Style	Right-angle
Connector Rotation	180° rotatable
Mounting	IEC metric flange
Frame	130 mm
Magnetic Stack	101.6 mm
Approx. Weight	Approx. 10.6 kg
Operating Temperature	Approx. 0 to 40 °C
Motor Classification	Low-inertia servo motor

The 10.2 N·m continuous torque rating provides the motor with substantial continuous mechanical output for a 130 mm frame.

The approximately 27.1 N·m peak torque rating provides additional short-duration torque for acceleration, positioning, and transient load conditions.

The 3000 rpm speed rating provides a useful balance between rotational speed and torque, making this motor suitable for many general-purpose industrial servo axes.

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4. Dimensions and Mechanical Specifications

The MPL-B4540F-MJ74AA is built around a 130 mm frame and a 101.6 mm magnetic stack.

These two dimensions are particularly important when evaluating machine installation space or replacing an existing servo motor.

Mechanical Parameter	Specification
Model	MPL-B4540F-MJ74AA
Frame Size	130 mm
Frame Dimension	130 mm / 5.12 in class
Frame Designation	45
Magnetic Stack Length	101.6 mm
Stack Designation	40
Mounting Standard	IEC metric
Mounting Type	Flange mount
Mounting Hole Type	Free mounting holes, Type FF
Shaft Configuration	Keyed shaft extension
Shaft Seal	No shaft seal
Connector	SpeedTEC DIN
Connector Orientation	Right-angle
Connector Rotation	Approximately 180°
Motor Envelope	130 mm frame × 101.6 mm stack class
Approx. Motor Weight	Approx. 10.6 kg

The exact overall motor envelope should be checked against the applicable mechanical drawing when designing an installation.

The 130 mm frame and 101.6 mm stack describe the principal motor body dimensions, while the final installation space is also affected by the shaft extension, flange arrangement, connector position, cable clearance, and mounting hardware.

For replacement applications, it is important to check not only the frame size but also the shaft configuration and connector orientation.

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5. Product Introduction

The Allen-Bradley MPL-B4540F-MJ74AA is a precision-oriented low-inertia servo motor designed for industrial automation.

It combines a compact 130 mm frame with a 101.6 mm magnetic stack, allowing the motor to deliver approximately 10.2 N·m of continuous stall torque and approximately 27.1 N·m of peak torque.

The motor operates at a rated speed of 3000 rpm.

Its multi-turn high-resolution absolute feedback system is designed for accurate position monitoring across multiple motor revolutions.

This makes it suitable for applications where the control system needs detailed information about motor position rather than simply basic speed feedback.

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

The integrated 24 V DC brake provides mechanical holding capability when the servo motor is stopped.

This is especially valuable on vertical axes and other applications where the machine load must remain stationary when motor torque is removed.

The SpeedTEC DIN right-angle connector also provides flexibility for machine integration, particularly where cable routing space is limited.

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6. Main Advantages

6.1 Low-Inertia Servo Design

One of the most important characteristics of the MPL-B4540F-MJ74AA is its low rotor inertia.

The rotor inertia is approximately 0.00052 kg·m².

A low-inertia rotor can respond rapidly to changes in commanded speed and position.

This is particularly useful for machines that repeatedly accelerate, decelerate, stop, and reverse.

Typical examples include indexing machines, packaging equipment, assembly systems, pick-and-place mechanisms, and automated inspection equipment.

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6.2 High Continuous Torque

The motor provides approximately 10.2 N·m of continuous stall torque.

This gives the motor useful continuous mechanical capability without requiring an excessively large motor frame.

The B4540F configuration therefore provides a practical balance between machine size and torque capacity.

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6.3 High Peak Torque

The approximately 27.1 N·m peak torque rating provides additional short-duration torque capability.

Peak torque is particularly useful during:

• Rapid acceleration
• Short positioning cycles
• High-load starting conditions
• Sudden load changes
• Indexing operations
• Dynamic machine movements

The peak rating should not be treated as a continuous operating torque. Continuous operation should remain within the appropriate continuous torque capability.

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6.4 3000 rpm Rated Speed

The 3000 rpm rating allows the motor to operate at a relatively high rotational speed while maintaining useful torque.

This makes it suitable for many machine axes where both speed and torque are important.

It is particularly well matched to:

• Packaging machinery
• Feed systems
• Printing equipment
• Indexing machines
• Material handling
• Assembly equipment
• Converting machinery

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6.5 Multi-Turn High-Resolution Absolute Feedback

The multi-turn absolute encoder is one of the major features of the MJ configuration.

It provides detailed position information over multiple revolutions.

This is useful for applications where the motor may rotate through many turns and the control system still needs accurate position information.

Typical applications include:

• Rotary positioning
• Ball-screw-driven axes
• Indexing systems
• Coordinated multi-axis machinery
• Precision assembly
• Automated inspection
• Motion synchronization

The high-resolution feedback also supports smooth servo-loop operation and accurate positioning.

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7. Integrated 24 V DC Brake

The integral 24 V DC brake is a major feature of the MPL-B4540F-MJ74AA.

The brake provides a mechanical holding function when the motor is stopped.

This is particularly important when the driven load can move because of gravity.

Typical applications include:

• Vertical positioning axes
• Z-axis systems
• Lift mechanisms
• Vertical transfer systems
• Material-handling lifts
• Automated storage equipment
• Tool positioning systems
• Vertical assembly mechanisms

The brake is primarily intended for holding rather than replacing normal servo-controlled deceleration.

During normal operation, the servo drive should normally control acceleration and deceleration.

The mechanical brake can then provide additional holding when the motor is stopped.

Correct brake sequencing is important to prevent unnecessary mechanical shock and excessive brake wear.

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8. Keyed Shaft Design

The MPL-B4540F-MJ74AA uses a keyed shaft extension.

The keyed shaft is a familiar industrial mechanical interface and is convenient for many existing machine designs.

It can be used with suitable:

• Couplings
• Gearboxes
• Pulleys
• Gears
• Timing-belt systems
• Rotary tables
• Rollers
• Feed mechanisms

A keyed shaft can be particularly useful when replacing an older servo motor that already uses a conventional keyed mechanical connection.

The coupling should be selected according to shaft dimensions, torque, speed, radial loading, axial loading, alignment, and machine duty cycle.

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9. SpeedTEC DIN Right-Angle Connector

The MPL-B4540F-MJ74AA uses a SpeedTEC DIN connector in a right-angle configuration.

The connector can be rotated through approximately 180 degrees.

This is useful when the motor is installed in a compact machine and the available space for cable routing is limited.

The rotatable connector can help accommodate different machine layouts without forcing the motor to be physically repositioned.

Advantages include:

• Flexible cable routing
• Reduced installation interference
• Easier machine integration
• Better use of restricted installation space
• Convenient cable orientation

Cable bending radius and connector clearance should still be considered during installation.

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10. Typical Applications

Application	Suitability	Main Advantages
Packaging Machinery	Excellent	Fast response and accurate indexing
Automated Assembly	Excellent	High-resolution feedback
Rotary Indexing	Excellent	Precise multi-turn position control
Pick-and-Place Systems	Excellent	Low rotor inertia
Material Handling	Very Good	Torque and controlled motion
Vertical Axes	Excellent	Integral 24 V brake
Printing Machinery	Excellent	Speed and position synchronization
Converting Machinery	Excellent	Coordinated servo motion
Labeling Equipment	Excellent	Repeatable positioning
Inspection Systems	Excellent	Accurate motion control
Machine Tools	Very Good	Stable servo operation
Feed Mechanisms	Excellent	Rapid acceleration and deceleration
Textile Machinery	Very Good	Controlled rotary speed
Robotics	Very Good	Dynamic response
Automated Storage Equipment	Very Good	Brake-equipped configuration

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11. Application in Packaging Machinery

Packaging machinery frequently requires short machine cycles.

A typical axis may need to accelerate rapidly, move to a precise location, stop, perform a packaging operation, and then repeat.

The low-inertia design of the MPL-B4540F-MJ74AA is well suited to these operating conditions.

The high-resolution multi-turn feedback helps maintain accurate motion control, while the peak torque capability provides additional capacity during acceleration.

The integral brake is useful when a machine mechanism must remain mechanically stationary during a stop.

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12. Application in Automated Assembly

Automated assembly equipment commonly uses several servo axes operating in coordination.

The MPL-B4540F-MJ74AA can be used for rotary positioning, indexing, transfer mechanisms, feeders, tooling systems, and other motion-control axes.

The multi-turn absolute feedback system provides detailed position information to the servo-control system.

The low-inertia rotor also helps the motor react quickly when the motion command changes.

This combination can help reduce settling time and improve repeatability when the machine is properly tuned.

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13. Application in Vertical Motion

The integral brake makes this motor especially suitable for vertical axes.

A vertical axis is continuously affected by gravity.

When servo torque is removed, the load can potentially move unless an appropriate holding mechanism is provided.

The integral 24 V DC brake provides an additional mechanical holding function.

Examples include:

• Vertical lifting platforms
• Z-axis machines
• Automated storage lifts
• Vertical tooling
• Robotic vertical axes
• Material-handling elevators
• Assembly machines
• Vertical transfer systems

The brake should be integrated into the machine’s control and safety architecture rather than treated as the only safety mechanism.

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14. Application in Rotary Indexing Machines

Rotary indexing systems often require rapid movement followed by accurate stopping.

The motor accelerates the mechanism, approaches the target position, decelerates, and holds the required position.

The low rotor inertia supports rapid speed changes.

The high-resolution multi-turn feedback provides detailed position information.

The 27.1 N·m peak torque capability provides additional capacity during acceleration.

The result is a servo motor configuration well suited to high-cycle indexing equipment.

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15. Application in Printing and Converting Machinery

Printing and converting machinery often requires accurate synchronization between several rotating axes.

Differences in speed or position can affect material registration, cutting accuracy, tension control, and product quality.

The MPL-B4540F-MJ74AA can be used in applications where accurate rotary speed and position control are required.

Its multi-turn high-resolution feedback is particularly useful when several servo axes must operate in coordinated motion.

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16. Application in Material Handling

Material-handling equipment often requires a combination of torque, speed, acceleration, and repeatable positioning.

The MPL-B4540F-MJ74AA provides approximately 10.2 N·m of continuous torque and approximately 27.1 N·m of peak torque.

The 3000 rpm speed rating allows relatively fast machine operation.

For horizontal conveyors and feed systems, the motor can provide controlled servo motion without relying on the brake during normal operation.

For vertical material-handling systems, the integral brake adds an important holding function.

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17. Five Same-Series or Closely Related Models

The following models are useful alternatives within the MPL family and provide different combinations of torque, speed, feedback, shaft, and brake configurations.

Model	Series	Speed	Continuous Torque	Peak Torque	Power	Frame / Stack	Feedback	Shaft	Brake	Approx. Weight
MPL-B4540F-MJ74AA	MPL Low-Inertia	3000 rpm	10.2 N·m	27.1 N·m	2.6 kW	130 / 101.6 mm	Multi-turn absolute	Keyed	24 V DC	Approx. 10.6 kg
MPL-B4540F-MJ72AA	MPL Low-Inertia	3000 rpm	10.2 N·m	27.1 N·m	2.6 kW	130 / 101.6 mm	Multi-turn absolute	Keyed	No	Approx. 8.6 kg
MPL-B4540F-MJ24AA	MPL Low-Inertia	3000 rpm	10.2 N·m	27.1 N·m	2.6 kW	130 / 101.6 mm	Multi-turn absolute	Keyed	24 V DC	Approx. 10.6 kg
MPL-B4530F-MJ74AA	MPL Low-Inertia	3000 rpm	Approx. 8.25 N·m	Approx. 20.3 N·m	Approx. 2.1 kW	130 / 76.2 mm	Multi-turn absolute	Keyed	24 V DC	Approx. 7.3 kg
MPL-B4560F-MJ74AA	MPL Low-Inertia	3000 rpm	Approx. 14.1 N·m	Approx. 34.4 N·m	3.2 kW	130 / 152.4 mm	Multi-turn absolute	Keyed	24 V DC	Approx. 11.8 kg

The MPL-B4540F-MJ72AA is particularly close to the target motor because it has essentially the same basic B4540F motor performance but without the integral brake.

The MPL-B4530F-MJ74AA is a shorter-stack alternative when less torque is required.

The MPL-B4560F-MJ74AA is a higher-torque alternative when the B4540F does not provide enough continuous or peak torque.

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18. Detailed Comparison of Related Models

MPL-B4540F-MJ72AA

The MPL-B4540F-MJ72AA is one of the closest alternatives to the MJ74AA.

It uses the same general 130 mm frame and 101.6 mm magnetic stack and provides approximately 10.2 N·m continuous torque and approximately 27.1 N·m peak torque.

The main difference is the absence of the integral 24 V DC brake.

It is therefore more suitable for horizontal or non-gravity-loaded axes where a mechanical holding brake is not required.

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MPL-B4540F-MJ24AA

The MPL-B4540F-MJ24AA is another closely related multi-turn configuration.

It retains the same basic motor performance and uses a keyed shaft and integral 24 V DC brake.

It can be considered when comparing different connector/configuration generations or when matching an existing machine’s cable and connector arrangement.

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MPL-B4530F-MJ74AA

The MPL-B4530F-MJ74AA has a shorter 76.2 mm magnetic stack.

It provides approximately 8.25 N·m continuous torque and approximately 20.3 N·m peak torque.

This makes it suitable when the application requires a smaller motor output than the B4540F but still needs multi-turn absolute feedback and a brake.

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MPL-B4560F-MJ74AA

The MPL-B4560F-MJ74AA provides a higher torque capability than the B4540F.

It offers approximately 14.1 N·m continuous torque and approximately 34.4 N·m peak torque.

It is therefore a logical step upward for heavier-duty axes.

Its 152.4 mm stack is longer than the 101.6 mm stack of the B4540F, so the machine’s available installation space must be checked.

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19. Five Widely Used Allen-Bradley Models for Comparison

The following models provide useful broader comparisons when selecting an Allen-Bradley servo motor.

Model	Series	Speed	Continuous Torque	Peak Torque	Power	Frame / Stack	Feedback	Brake	Approx. Weight
MPL-B4530K-MJ74AA	MPL Low-Inertia	4000 rpm	Approx. 8.25 N·m	Approx. 20.3 N·m	Approx. 2.6 kW	130 mm / 76.2 mm class	Multi-turn absolute	24 V DC	Approx. 8 kg class
MPL-B4540F-HK74AA	MPL Low-Inertia	3000 rpm	10.2 N·m	27.1 N·m	2.6 kW	130 mm / 101.6 mm	High-resolution	24 V DC	Approx. 10–11 kg
MPL-B4540F-MJ74AA	MPL Low-Inertia	3000 rpm	10.2 N·m	27.1 N·m	2.6 kW	130 mm / 101.6 mm	Multi-turn absolute	24 V DC	Approx. 10.6 kg
MPL-B4560F-MJ74AA	MPL Low-Inertia	3000 rpm	14.1 N·m	34.4 N·m	3.2 kW	130 mm / 152.4 mm	Multi-turn absolute	24 V DC	Approx. 11.8 kg
MPL-B540K-MJ74AA	MPL Low-Inertia	4000 rpm	19.4 N·m	48.6 N·m	5.4 kW	165 mm / 101.6 mm class	Multi-turn absolute	24 V DC	Approx. 15 kg

These models cover several common application requirements.

The smaller B4530 configuration is useful when lower torque is sufficient and a shorter stack is preferred.

The B4540F configurations provide a balanced combination of torque and size.

The B4560F provides greater torque while retaining the same general frame family.

The B540K moves to a substantially larger motor class for applications requiring considerably higher torque and power.

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20. Model Selection Guide

Application Requirement	Recommended Model	Main Reason
Multi-turn absolute feedback + brake	MPL-B4540F-MJ74AA	Balanced 3000 rpm / 10.2 N·m configuration
Same basic motor without brake	MPL-B4540F-MJ72AA	Lower-complexity non-brake version
Multi-turn configuration with alternative connector generation	MPL-B4540F-MJ24AA	Closely related MJ configuration
Lower torque requirement	MPL-B4530F-MJ74AA	Shorter stack and lower torque
Higher torque requirement	MPL-B4560F-MJ74AA	14.1 N·m continuous torque
High-resolution feedback + brake	MPL-B4540F-HK74AA	Alternative feedback configuration
Higher speed requirement	MPL-B4530K-MJ74AA	4000 rpm class
High torque and high speed	MPL-B540K-MJ74AA	Larger 4000 rpm motor
Horizontal positioning axis	MPL-B4540F-MJ72AA	Brake generally not required
Vertical positioning axis	MPL-B4540F-MJ74AA	Integral 24 V DC brake

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21. MJ74AA Versus MJ72AA

The most direct comparison is between the MPL-B4540F-MJ74AA and MPL-B4540F-MJ72AA.

Both models use the same general B4540F motor platform.

Parameter	MPL-B4540F-MJ74AA	MPL-B4540F-MJ72AA
Rated Speed	3000 rpm	3000 rpm
Continuous Torque	10.2 N·m	10.2 N·m
Peak Torque	27.1 N·m	27.1 N·m
Rated Power	Approx. 2.6 kW	Approx. 2.6 kW
Frame	130 mm	130 mm
Stack	101.6 mm	101.6 mm
Feedback	Multi-turn absolute	Multi-turn absolute
Shaft	Keyed	Keyed
Brake	24 V DC	None
Rotor Inertia	Approx. 0.00052 kg·m²	Approx. 0.00052 kg·m²
Approx. Weight	Approx. 10.6 kg	Approx. 8.6 kg
Typical Application	Vertical / holding axes	Horizontal / non-holding axes

If the machine needs to mechanically hold a load after the servo motor stops, the MJ74AA is generally the better configuration.

If a holding brake is unnecessary, the MJ72AA can provide a simpler and lighter solution.

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22. MJ74AA Versus HK74AA

Another useful comparison is between the MJ74AA and HK74AA.

Both models use the same basic B4540F motor platform, 130 mm frame, 101.6 mm stack, 3000 rpm speed class, and approximately 10.2 N·m continuous torque.

The major difference is the feedback configuration.

Parameter	MPL-B4540F-MJ74AA	MPL-B4540F-HK74AA
Speed	3000 rpm	3000 rpm
Continuous Torque	10.2 N·m	10.2 N·m
Peak Torque	27.1 N·m	27.1 N·m
Frame	130 mm	130 mm
Stack	101.6 mm	101.6 mm
Feedback	Multi-turn high-resolution absolute	High-resolution feedback
Shaft	Keyed	Keyless
Brake	24 V DC	24 V DC
Main Difference	Multi-turn feedback + keyed shaft	High-resolution feedback + keyless shaft

The MJ74AA is therefore particularly useful when multi-turn absolute feedback and a conventional keyed shaft are desired.

The HK74AA is more appropriate when the machine design calls for the alternative high-resolution/keyless configuration.

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23. Servo Drive Compatibility

The MPL-B4540F-MJ74AA is intended to operate as part of a complete servo motion-control system.

The servo drive must be correctly matched to the motor’s:

• Voltage class
• Rated current
• Continuous torque
• Peak torque
• Feedback system
• Brake circuit
• Motor cable
• Feedback cable
• Operating speed
• Regenerative requirements
• Load inertia

Correct drive selection is essential for obtaining the intended performance.

The drive must also be configured for the appropriate motor feedback and brake characteristics.

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24. Mechanical Installation

The 130 mm frame should be checked carefully against the available machine space.

The installation should provide sufficient clearance for:

• Motor body
• Mounting flange
• Shaft coupling
• Power connector
• Feedback connector
• Brake wiring
• Motor cables
• Cooling
• Maintenance access

The right-angle connector provides useful flexibility, but cable clearance should still be considered.

The shaft should be accurately aligned with the driven mechanism.

Misalignment can cause excessive radial or axial loading and may result in increased vibration, coupling wear, bearing stress, or reduced operating life.

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25. Load Inertia and Servo Tuning

Although the MPL-B4540F-MJ74AA has relatively low rotor inertia, the machine load can still have a major influence on servo performance.

The reflected load inertia should be evaluated during system design.

A large difference between motor inertia and reflected load inertia can affect:

• Acceleration
• Deceleration
• Positioning time
• Settling time
• Overshoot
• Vibration
• Servo stability
• Mechanical resonance

Proper servo tuning is therefore essential.

The motor should be evaluated together with the complete mechanical transmission system rather than as an isolated component.

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26. Brake Control Considerations

The integral 24 V DC brake should generally be used as a holding device.

During normal motion, the servo drive should control acceleration and deceleration.

The brake can then be engaged when the axis is stationary and holding is required.

This approach reduces unnecessary mechanical stress and brake wear.

For vertical axes, the brake-control sequence should be carefully designed so that the brake is not released before the servo system has established sufficient torque to support the load.

Likewise, when stopping a vertical axis, the servo should normally bring the axis to a controlled stop before the mechanical brake is engaged.

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27. Maintenance

Regular inspection is recommended for industrial servo systems.

Important inspection areas include:

• Motor mounting bolts
• Shaft coupling
• Shaft key
• Feedback connector
• Motor power connector
• Brake wiring
• Feedback cable
• Motor temperature
• Abnormal vibration
• Abnormal noise
• Mechanical alignment
• Grounding
• Signs of contamination
• Positioning accuracy

A sudden change in motor temperature, noise, vibration, or positioning performance should be investigated rather than ignored.

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28. Common Causes of Servo Problems

If the motor does not perform correctly, the motor itself is not necessarily the source of the problem.

Possible causes include:

• Incorrect drive configuration
• Incorrect feedback settings
• Damaged feedback cable
• Incorrect motor cable
• Poor grounding
• Mechanical binding
• Excessive load inertia
• Shaft misalignment
• Excessive radial load
• Excessive axial load
• Brake-control problems
• Excessive ambient temperature
• Incorrect servo tuning

A complete troubleshooting process should therefore examine both the electrical and mechanical sides of the servo system.

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29. Advantages at a Glance

Feature	Advantage
Low-Inertia Rotor	Fast acceleration and deceleration
3000 rpm Rated Speed	Suitable for high-cycle machinery
10.2 N·m Continuous Torque	Strong continuous mechanical output
27.1 N·m Peak Torque	High short-duration acceleration capability
2.6 kW Rated Output	Suitable for medium-duty servo axes
Multi-Turn Absolute Feedback	Accurate multi-revolution position information
Keyed Shaft	Conventional industrial mechanical connection
Integral 24 V DC Brake	Mechanical holding capability
130 mm Frame	Compact industrial installation
101.6 mm Stack	Good torque-to-size balance
SpeedTEC DIN Connector	Practical industrial connection
Right-Angle Connector	Flexible cable routing
180° Connector Rotation	Easier installation
IEC Metric Flange	Standard industrial mounting arrangement

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30. Overall Product Assessment

The Allen-Bradley MPL-B4540F-MJ74AA is a well-balanced industrial servo motor for applications requiring precision feedback, dynamic response, useful torque density, and mechanical holding capability.

Its 130 mm frame and 101.6 mm magnetic stack provide a compact industrial package while delivering approximately 10.2 N·m of continuous stall torque and approximately 27.1 N·m of peak torque.

The 3000 rpm rated speed makes it suitable for a broad range of machine axes.

The low rotor inertia is especially valuable for high-cycle machinery where rapid acceleration and deceleration are important.

The multi-turn high-resolution absolute encoder provides detailed position feedback across multiple revolutions.

The keyed shaft provides a conventional and robust mechanical connection for many types of machine transmissions.

The integral 24 V DC brake makes the model particularly attractive for vertical axes and other applications where a load must remain mechanically held when servo torque is removed.

The right-angle SpeedTEC DIN connector also provides useful installation flexibility in compact machines.

Compared with the non-brake MPL-B4540F-MJ72AA, the MJ74AA is better suited to applications requiring mechanical holding.

Compared with the shorter-stack MPL-B4530F-MJ74AA, the MJ74AA provides greater continuous and peak torque.

Compared with the larger MPL-B4560F-MJ74AA, the MJ74AA occupies a smaller overall motor class while still providing substantial torque.

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31. Quick Technical Reference

Category	Specification
Brand	Allen-Bradley
Product Family	MP-Series
Product Series	MPL Low-Inertia Servo Motors
Model	MPL-B4540F-MJ74AA
Motor Type	Brushless Permanent-Magnet AC Servo Motor
Voltage Class	460 V AC
Rated Speed	3000 rpm
Maximum Speed	3000 rpm
Continuous Stall Torque	Approx. 10.2 N·m
Peak Torque	Approx. 27.1 N·m
Rated Output	Approx. 2.6 kW
Rotor Inertia	Approx. 0.00052 kg·m²
Frame Size	130 mm
Frame Designation	45
Magnetic Stack	101.6 mm
Stack Designation	40
Feedback	Multi-turn high-resolution absolute encoder
Shaft	Keyed shaft extension
Brake	24 V DC integral brake
Connector	SpeedTEC DIN
Connector Style	Right-angle
Connector Rotation	Approximately 180°
Mounting	IEC metric flange
Mounting Holes	Free mounting holes, Type FF
Approx. Weight	Approx. 10.6 kg
Typical Operating Temperature	0 to 40 °C
Typical Applications	Packaging, assembly, indexing, material handling, printing, converting, inspection, machine tools and vertical axes

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32. Final Summary

The Allen-Bradley MPL-B4540F-MJ74AA is a 460 V class MPL low-inertia brushless rotary servo motor designed for demanding industrial motion-control applications.

It provides approximately 10.2 N·m of continuous stall torque, approximately 27.1 N·m of peak torque, approximately 2.6 kW of rated output, and a rated speed of 3000 rpm.

The motor uses a 130 mm frame and 101.6 mm magnetic stack, giving it a useful balance between physical size and torque capacity.

Its multi-turn high-resolution absolute encoder provides accurate position feedback over multiple motor revolutions.

The keyed shaft makes the motor convenient for conventional industrial mechanical transmission systems.

The integral 24 V DC brake is a major advantage for vertical axes, lifting mechanisms, positioning systems, and other applications where the load must remain mechanically held after the motor stops.

The low-inertia design supports rapid acceleration and deceleration, making the motor particularly useful in high-cycle automated machinery.

The MPL-B4540F-MJ74AA is therefore a strong choice for packaging machines, automated assembly equipment, rotary indexing systems, printing and converting equipment, material handling, inspection machinery, machine tools, and vertical servo axes.

For a non-brake version with similar core performance, the MPL-B4540F-MJ72AA is a close alternative.

For lower torque requirements, the MPL-B4530F-MJ74AA provides a shorter stack.

For higher torque requirements, the MPL-B4560F-MJ74AA is a suitable step upward.

For a different feedback and shaft configuration, the MPL-B4540F-HK74AA provides another closely related option.

Overall, the MPL-B4540F-MJ74AA combines low inertia, 3000 rpm operation, 10.2 N·m continuous torque, 27.1 N·m peak torque, multi-turn absolute feedback, a keyed shaft, and an integral 24 V DC brake in a compact 130 mm-frame servo motor.