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MPL-B540D-MJ74AA Servo Motor – Complete Product Introduction and Technical Guide

1. Product Overview

The MPL-B540D-MJ74AA is a low-inertia brushless AC rotary servo motor designed for industrial motion-control systems that require accurate positioning, dependable speed regulation, strong continuous torque, and absolute multi-turn feedback.

It is part of the MPL Series low-inertia servo motor family and uses a 165 mm frame with a 101.6 mm magnetic stack. The motor is rated for the 460 V class and operates in a 480 V AC servo system environment. Its rated speed is 2000 rpm, with approximately 3.4 kW rated output, 19.4 N·m continuous stall torque, and 41.0 N·m peak stall torque.

The MJ74AA configuration combines a multi-turn high-resolution absolute encoder, keyed shaft extension, 24 V DC holding brake, and right-angle SpeedTEC DIN connector.

This combination makes the motor especially useful when a machine requires accurate multi-revolution position information and also needs an integrated brake for holding a load when servo torque is removed.

The motor is suitable for a wide range of industrial machinery, including machine tools, automated assembly equipment, packaging machines, material-handling systems, rotary positioning equipment, ball-screw axes, indexing systems, and other automated production equipment.

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2. Brand and Product Series

Item	Specification
Brand	Allen-Bradley
Product Series	MPL Series
Product Family	MP-Series Low-Inertia Servo Motors
Motor Type	Brushless AC Rotary Servo Motor
Product Category	Industrial Servo Motor
Model	MPL-B540D-MJ74AA
Voltage Class	460 V
System Voltage	480 V AC
Frame Size	165 mm
Frame Size, Imperial	6.50 in
Magnetic Stack	101.6 mm
Stack Length, Imperial	4.0 in
Rated Speed	2000 rpm
Maximum Speed	2000 rpm
Rated Output	Approx. 3.4 kW
Continuous Stall Torque	19.4 N·m
Peak Stall Torque	41.0 N·m
Feedback	Multi-turn high-resolution absolute encoder
Shaft	Keyed shaft extension
Brake	24 V DC holding brake
Connector	SpeedTEC DIN
Connector Orientation	Right-angle
Connector Rotation	180° rotatable
Mounting	IEC metric
Mounting Hole Type	Free mounting holes, Type FF

The exact product configuration identifies the motor as a 165 mm frame, 101.6 mm stack, 2000 rpm, multi-turn absolute-feedback motor with a keyed shaft, right-angle rotatable connector, and 24 V DC brake.

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3. Product Series Introduction

The MPL Series is a family of low-inertia brushless servo motors intended for precision industrial motion control.

The series covers a wide range of motor sizes, speeds, torque ratings, feedback arrangements, shaft configurations, and brake options.

Within this family, the B540D represents a 2000 rpm motor class with a relatively high continuous torque capability compared with smaller B520K motors.

The B540D platform uses a 165 mm frame and 101.6 mm magnetic stack, giving it substantially more active motor length than the 50.8 mm-stack B520K.

The result is a motor that emphasizes torque capacity and controlled 2000 rpm operation, rather than the very high shaft speed associated with the 4000 rpm B520K and B540K configurations.

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4. Model Number Explanation

The model number MPL-B540D-MJ74AA contains several configuration identifiers.

Model Code	General Meaning
MPL	MPL low-inertia brushless servo motor family
B	460 V class
5	Frame 5 / 165 mm frame
40	101.6 mm magnetic stack
D	2000 rpm speed class
M	Multi-turn high-resolution absolute feedback
J	Keyed shaft extension
7	SpeedTEC DIN right-angle connector
4	24 V DC holding brake
AA	Standard configuration suffix

The model can therefore be summarized as a:

165 mm frame + 101.6 mm stack + 2000 rpm + multi-turn absolute encoder + keyed shaft + 24 V DC brake servo motor.

This combination is particularly useful for machinery where both multi-revolution positioning and mechanical holding are important.

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5. Main Technical Parameters

The B540D motor platform is rated at approximately 3.4 kW, with 19.4 N·m continuous stall torque and 41.0 N·m peak stall torque. The published rotor inertia is approximately 0.00147 kg·m².

Parameter	Specification
Model	MPL-B540D-MJ74AA
Brand	Allen-Bradley
Series	MPL Series
Motor Type	Low-inertia brushless AC servo motor
Voltage Class	460 V
System Voltage	480 V AC
Rated Output	Approx. 3.4 kW
Rated Speed	2000 rpm
Maximum Speed	2000 rpm
Continuous Stall Torque	19.4 N·m
Peak Stall Torque	41.0 N·m
Rotor Inertia	Approx. 0.00147 kg·m²
Continuous Stall Current	Approx. 10.5 A
Peak Stall Current	Approx. 23.0 A
Frame Size	165 mm
Magnetic Stack	101.6 mm
Feedback	Multi-turn high-resolution absolute encoder
Feedback Resolution	Sin/Cos, 1024 cycles/rev
Feedback Protocol	Hiperface
Shaft	Keyed shaft extension
Shaft Key	Yes
Shaft Seal	No
Brake	24 V DC holding brake
Connector	SpeedTEC DIN
Connector Type	Right-angle
Connector Rotation	180° rotatable
Mounting	IEC metric
Mounting Holes	Free mounting holes / Type FF
Approx. Weight	17.6 kg
Motor Family Weight Reference	Approx. 15 kg before configuration-specific brake addition
Operating Temperature	Up to approximately 40 °C
Overall Envelope	Verify exact mechanical drawing

The 19.4 N·m continuous torque, 41.0 N·m peak torque, 3.4 kW output, 2000 rpm speed, and 0.00147 kg·m² rotor inertia correspond to the B540D motor class.

The exact MJ74AA configuration includes the 24 V DC brake, which increases the overall motor weight compared with the base no-brake B540D configuration. One published exact-model listing gives a weight of 38.75 lb, equivalent to approximately 17.6 kg.

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6. Dimensions and Mechanical Specifications

The most important mechanical dimensions for this model are the 165 mm frame size and 101.6 mm magnetic stack length.

The 165 mm frame corresponds to approximately 6.50 inches, while the 101.6 mm stack corresponds to approximately 4.0 inches.

Mechanical Parameter	Specification
Model	MPL-B540D-MJ74AA
Frame Size	165 mm
Frame Size, Imperial	6.50 in
Magnetic Stack Length	101.6 mm
Stack Length, Imperial	4.0 in
Mounting Type	IEC metric flange mount
Mounting Hole Style	Free mounting holes / Type FF
Shaft Configuration	Keyed
Shaft Key	Yes
Shaft Seal	No
Connector	SpeedTEC DIN
Connector Position	Right-angle
Connector Rotation	180°
Brake	24 V DC
Approx. Weight	17.6 kg
Full Overall Length	Verify exact mechanical drawing
Full Motor Height	Verify exact mechanical drawing
Full Motor Width / Diameter	Verify exact mechanical drawing
Shaft Projection	Verify exact mechanical drawing
Mounting Bolt Circle	Verify exact mechanical drawing

The product’s official configuration identifies the 165 mm frame and 101.6 mm stack dimensions.

The frame size and magnetic stack should not be mistaken for the complete motor envelope.

For machine-frame design, enclosure clearance, coupling alignment, shaft projection, mounting-hole preparation, and cable routing, the detailed mechanical drawing should always be used.

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7. Weight

Weight is an important consideration when this motor is installed on a moving machine axis, rotary table, vertical slide, robotic mechanism, or other structure with strict mass limitations.

The general B540D motor-family data lists approximately 15 kg for the basic motor configuration.

The exact MJ74AA configuration includes a 24 V DC holding brake, and an exact-model listing gives a weight of 38.75 lb, or approximately 17.6 kg.

Weight Parameter	Value
Model	MPL-B540D-MJ74AA
Approx. Exact-Configuration Weight	17.6 kg
Approx. Base B540D Family Weight	15 kg
Brake	24 V DC
Frame	165 mm
Stack	101.6 mm

For machine structural calculations, use 17.6 kg as a practical reference for the brake-equipped MJ74AA configuration, while the final engineering value should be confirmed against the exact motor drawing and delivered unit.

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8. Electrical Characteristics

The MPL-B540D-MJ74AA is designed for the 460 V class and is used in a 480 V AC servo system environment.

Its rated output is approximately 3.4 kW at 2000 rpm.

The motor provides 19.4 N·m continuous stall torque and approximately 41.0 N·m peak stall torque.

Electrical Parameter	Specification
Model	MPL-B540D-MJ74AA
Voltage Class	460 V
System Voltage	480 V AC
Rated Power	3.4 kW
Rated Speed	2000 rpm
Maximum Speed	2000 rpm
Continuous Stall Torque	19.4 N·m
Peak Stall Torque	41.0 N·m
Continuous Stall Current	Approx. 10.5 A
Peak Stall Current	Approx. 23.0 A
Rotor Inertia	Approx. 0.00147 kg·m²
Brake Voltage	24 V DC
Feedback	Absolute multi-turn
Feedback Resolution	1024 cycles/rev Sin/Cos

Actual drive current depends on the machine load, acceleration profile, duty cycle, operating temperature, and servo-drive configuration.

The continuous and peak current values should therefore be used as motor-selection reference values rather than as a substitute for complete servo-drive sizing.

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9. Torque Characteristics

Torque is one of the strongest reasons to select the B540D platform.

The motor provides approximately 19.4 N·m of continuous stall torque and 41.0 N·m of peak stall torque.

This places it above the B520K in continuous torque while keeping the motor within the same general 165 mm frame class.

Torque Parameter	Specification
Model	MPL-B540D-MJ74AA
Continuous Stall Torque	19.4 N·m
Peak Stall Torque	41.0 N·m
Rated Speed	2000 rpm
Rated Power	3.4 kW
Rotor Inertia	0.00147 kg·m²

The 41.0 N·m peak value is intended for short-duration dynamic operation.

The actual allowable peak torque depends on acceleration time, duty cycle, thermal conditions, drive configuration, and the machine’s motion profile.

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10. 2000 RPM Speed Class

The D speed designation corresponds to the 2000 rpm configuration.

A 2000 rpm motor is often a good choice when the machine requires relatively strong torque without needing the extremely high motor speed of a 4000 rpm servo.

This speed class can work particularly well with ball screws, gear reductions, indexing mechanisms, rotary tables, material-handling systems, and machine-tool feed axes.

For a ball-screw axis, for example, the designer can select the screw pitch and reduction ratio around a 2000 rpm motor speed without unnecessarily forcing the motor to operate at very high rotational speed.

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11. Multi-Turn Absolute Feedback

The M in the model designation indicates the multi-turn high-resolution absolute feedback configuration.

The feedback is specified as an absolute multi-turn encoder, with technical data identifying 1024 Sin/Cos cycles per revolution and Hiperface protocol.

This is particularly useful for applications where the motor shaft rotates through multiple revolutions during normal machine operation.

A single-turn feedback system primarily provides position information within one revolution, while a multi-turn system is designed to distinguish position across multiple revolutions.

This makes the multi-turn configuration especially suitable for long-travel linear axes, ball-screw mechanisms, rotary indexing systems, and other mechanisms where the motor makes many rotations between machine positions.

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12. Advantages of Multi-Turn Feedback

The multi-turn feedback arrangement can provide several practical advantages.

First, it gives the control system useful position information over multiple motor revolutions.

Second, it is well suited to mechanically long-travel systems.

Third, it can simplify machine position management where the motor continuously rotates through several turns during a normal operating cycle.

Fourth, it can be useful in applications where accurate position recovery is important after a stop or restart.

Typical applications include:

• Ball-screw linear axes
• Machine-tool feed axes
• Rotary positioning tables
• Long-travel automated equipment
• Material-handling mechanisms
• Automated assembly axes
• Servo-driven lifting mechanisms
• Multi-revolution indexing systems

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13. Keyed Shaft Configuration

The J configuration indicates a keyed shaft extension.

A keyed shaft remains one of the most familiar mechanical interfaces in industrial machinery.

It is convenient for applications using keyed couplings, gears, pulleys, sprockets, or other transmission components that require a mechanical key.

Shaft Parameter	Specification
Model	MPL-B540D-MJ74AA
Shaft Type	Keyed
Shaft Key	Yes
Shaft Seal	No
Typical Coupling	Keyed coupling
Typical Transmission	Gear, pulley, coupling, sprocket
Main Benefit	Familiar and robust mechanical connection

A keyed shaft can be particularly advantageous when the motor is replacing an existing servo motor with the same shaft style.

It can reduce the amount of mechanical modification required during replacement.

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14. Integrated 24 V DC Holding Brake

One of the most important differences between the MJ72AA and MJ74AA versions is the brake.

The MJ74AA configuration includes a 24 V DC holding brake.

The brake can be useful when the motor must hold a load after servo torque has been removed.

This is particularly important in vertical-axis applications.

Examples include:

• Vertical slides
• Z-axis mechanisms
• Lifting systems
• Gravity-loaded positioning axes
• Vertical ball-screw systems
• Holding mechanisms
• Machines requiring mechanical position retention during shutdown

The brake should normally be regarded as a holding mechanism rather than the primary dynamic stopping device.

For high-speed moving loads, the servo system should generally control deceleration before the holding brake is applied.

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15. Brake Advantages

The integrated brake provides several practical advantages.

A machine does not need to install a completely separate motor-side holding brake when the application is compatible with the integrated brake arrangement.

This can simplify the mechanical structure.

It can also reduce the space required around the motor.

For vertical axes, the brake can provide an important layer of mechanical holding when servo torque is unavailable.

Brake Feature	Specification
Model	MPL-B540D-MJ74AA
Brake Type	Holding brake
Brake Voltage	24 V DC
Integrated Brake	Yes
Primary Purpose	Holding
Typical Application	Vertical and gravity-loaded axes
Dynamic Stopping	Normally controlled by servo system
Brake Configuration	MJ74AA

Proper brake sizing and safety design remain necessary for every individual machine.

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16. SpeedTEC DIN Right-Angle Connector

The motor uses a SpeedTEC DIN right-angle connector.

The connector is also specified as 180° rotatable, which provides additional installation flexibility.

This arrangement is particularly useful in compact machine designs.

A straight connector can require significant clearance behind a motor.

A right-angle connector can route the cable more closely along the machine frame.

The 180° rotation feature provides additional freedom when deciding which direction the cable should leave the motor.

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17. IEC Metric Mounting

The motor uses IEC metric mounting and free mounting holes identified as Type FF.

This makes the motor suitable for conventional industrial machine structures.

When installing the motor, the following items should be checked:

• Mounting-hole dimensions
• Mounting-plate thickness
• Shaft projection
• Shaft diameter
• Keyway dimensions
• Coupling dimensions
• Motor body clearance
• Connector clearance
• Brake clearance
• Cable bending radius
• Overall motor length

The 165 mm frame designation provides the basic mechanical class, but the complete mechanical drawing should be used for final installation design.

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18. Low-Inertia Design

The MPL family is designed around low-inertia brushless servo motor technology.

The B540D has approximately 0.00147 kg·m² rotor inertia.

Low rotor inertia can improve the dynamic response of the servo axis.

When the motor is required to accelerate and decelerate repeatedly, less torque is consumed accelerating the rotor itself.

This can be particularly valuable in high-cycle machinery.

The final dynamic performance, however, depends on the complete mechanical system.

Load inertia, gearbox ratio, coupling inertia, ball-screw inertia, machine friction, and servo tuning all affect the actual response.

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19. Main Product Advantages

19.1 Strong Continuous Torque

The 19.4 N·m continuous torque rating provides a useful torque reserve for medium-duty industrial motion systems.

Compared with the B520K, the B540D provides significantly greater continuous torque.

This makes it more suitable for applications where load torque is more important than maximum motor speed.

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19.2 High Peak Torque

The 41.0 N·m peak torque capability provides additional short-duration torque for acceleration and transient loads.

This can be useful when a machine repeatedly starts and stops or when the load changes rapidly during the motion cycle.

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19.3 Multi-Turn Absolute Feedback

The multi-turn encoder is a major advantage for long-travel and multi-revolution applications.

It is especially suitable for ball-screw axes and rotary positioning mechanisms.

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19.4 Integrated Holding Brake

The 24 V DC brake is an important advantage for vertical axes.

It provides a dedicated holding function without requiring a separate external motor brake.

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19.5 Keyed Shaft

The keyed shaft provides a conventional and widely compatible mechanical interface.

It is particularly useful for existing machine designs based on keyed couplings.

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19.6 2000 RPM Speed

The 2000 rpm speed class provides a useful balance between torque and speed.

It is suitable for applications where 4000 rpm is unnecessary.

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19.7 Compact 165 mm Frame

The 165 mm frame gives the motor a relatively substantial torque capability without requiring a significantly larger frame class.

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19.8 Flexible Connector Arrangement

The right-angle and 180° rotatable connector can simplify cable routing in compact machinery.

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20. Typical Applications

CNC Machine Tools

The MPL-B540D-MJ74AA can be used for servo-controlled machine-tool axes where accurate positioning, moderate motor speed, and relatively high torque are required.

The multi-turn feedback is particularly useful for ball-screw-driven linear axes.

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Ball-Screw Linear Axes

This is one of the most natural applications for the motor.

A ball screw can require multiple motor revolutions for relatively small linear movements.

The multi-turn absolute encoder is therefore well matched to this type of motion system.

The 2000 rpm speed class can also provide a good balance between linear speed and available torque.

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Vertical Machine Axes

The integrated 24 V DC brake makes this configuration particularly interesting for vertical axes.

For example, a vertical slide may require the motor to provide servo torque during movement while using the brake to hold the axis when the servo system is disabled.

The machine’s complete safety architecture must determine the correct brake control sequence.

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Packaging Machinery

Packaging machines often require synchronized movement between multiple axes.

The B540D can be used for:

• Feeding
• Indexing
• Cutting
• Forming
• Positioning
• Conveyor synchronization
• Rotary mechanisms

The combination of multi-turn feedback and moderate speed can be useful for continuous or cyclic machinery.

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Automated Assembly Equipment

Automated assembly machines often require repeated positioning over multiple revolutions.

The motor’s feedback system can provide accurate position information while the 19.4 N·m continuous torque rating provides useful capacity for medium-duty mechanisms.

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Material Handling

Material-handling systems can include long-travel positioning axes, conveyors, transfer mechanisms, and lifting systems.

The integrated brake can be especially useful when a mechanism must hold position during a stop.

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Rotary Indexing Systems

Rotary indexing systems require accurate angular positioning and repeatable acceleration and deceleration.

The multi-turn feedback provides useful position information, while the 19.4 N·m continuous torque allows the motor to handle moderate mechanical loads.

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21. Recommended Same-Series or Closely Related Models

The following models are useful for comparing different motor sizes and performance levels within the same general MPL family.

Model	Speed	Power	Continuous Torque	Peak Torque	Rotor Inertia	Frame / Stack	Approx. Weight
MPL-B520K	4000 rpm	3.5 kW	10.7 N·m	23.2 N·m	0.000783 kg·m²	165 / 50.8 mm	9.8 kg
MPL-B540D	2000 rpm	3.4 kW	19.4 N·m	41.0 N·m	0.00147 kg·m²	165 / 101.6 mm	15 kg
MPL-B540K	4000 rpm	5.4 kW	19.4 N·m	48.6 N·m	0.00147 kg·m²	165 / 101.6 mm	Approx. 15 kg class
MPL-B560F	3000 rpm	5.5 kW	26.8 N·m	67.8 N·m	0.00213 kg·m²	165 / 152.4 mm	20.2 kg
MPL-B580F	3000 rpm	7.1 kW	34.0 N·m	87.0 N·m	0.00289 kg·m²	165 / 203.2 mm	25.4 kg

The family specifications show the B540D at 3.4 kW and 2000 rpm, the B540K at 5.4 kW and 4000 rpm, the B560F at 5.5 kW and 3000 rpm, and the B580F at 7.1 kW and 3000 rpm.

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22. Five Closely Related Configuration Models

For applications where the B540D motor size is appropriate but the mechanical configuration needs to change, the following models are useful comparison choices.

Model	Feedback	Shaft	Brake	Speed	Power	Continuous Torque
MPL-B540D-MJ72AA	Multi-turn absolute	Keyed	No	2000 rpm	3.4 kW	19.4 N·m
MPL-B540D-MJ74AA	Multi-turn absolute	Keyed	24 V DC	2000 rpm	3.4 kW	19.4 N·m
MPL-B540D-MK72AA	Multi-turn absolute	Keyless	No	2000 rpm	3.4 kW	19.4 N·m
MPL-B540D-MK74AA	Multi-turn absolute	Keyless	24 V DC	2000 rpm	3.4 kW	19.4 N·m
MPL-B540K-MJ74AA	Multi-turn configuration	Keyed	24 V DC	4000 rpm	5.4 kW	19.4 N·m

The first four choices are primarily configuration alternatives around the B540D motor platform.

The main differences are the shaft arrangement and brake option.

The B540K configuration is a higher-speed alternative when the machine requires 4000 rpm operation while maintaining a similar 165 mm frame and 101.6 mm stack class.

Exact feedback suffixes should always be checked against the required drive and machine-control architecture before substitution.

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23. Five Popular Models for Broader Brand Comparison

The following motor classes provide a useful overview of the broader MPL product range.

Model	Rated Speed	Rated Power	Continuous Torque	Peak Torque	Rotor Inertia	Approx. Weight
MPL-B4530K	4000 rpm	2.6 kW	8.25 N·m	20.3 N·m	0.00040 kg·m²	7.3 kg
MPL-B520K	4000 rpm	3.5 kW	10.7 N·m	23.2 N·m	0.000783 kg·m²	9.8 kg
MPL-B540D	2000 rpm	3.4 kW	19.4 N·m	41.0 N·m	0.00147 kg·m²	15 kg
MPL-B560F	3000 rpm	5.5 kW	26.8 N·m	67.8 N·m	0.00213 kg·m²	20.2 kg
MPL-B580F	3000 rpm	7.1 kW	34.0 N·m	87.0 N·m	0.00289 kg·m²	25.4 kg

These values represent motor-family performance classes. Actual finished-motor weight can vary depending on feedback, shaft, connector, brake, and other configuration choices.

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24. B540D-MJ74AA vs. B540D-MJ72AA

The two models are extremely similar mechanically and electrically.

The most important difference is the integrated brake.

Parameter	MPL-B540D-MJ74AA	MPL-B540D-MJ72AA
Speed	2000 rpm	2000 rpm
Power	3.4 kW	3.4 kW
Continuous Torque	19.4 N·m	19.4 N·m
Peak Torque	41.0 N·m	41.0 N·m
Feedback	Multi-turn absolute	Multi-turn absolute
Shaft	Keyed	Keyed
Brake	24 V DC	No brake
Frame	165 mm	165 mm
Stack	101.6 mm	101.6 mm
Rotor Inertia	Approx. 0.00147 kg·m²	Approx. 0.00147 kg·m²
Weight	Approx. 17.6 kg	Approx. 15 kg

If the machine needs a motor-mounted holding brake, the MJ74AA is the appropriate direction.

If the machine does not require a brake and lower motor weight is desirable, the MJ72AA is the simpler configuration.

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25. B540D-MJ74AA vs. B540K

The B540K is a higher-speed member of the same general motor family.

Parameter	MPL-B540D-MJ74AA	MPL-B540K
Speed	2000 rpm	4000 rpm
Power	3.4 kW	5.4 kW
Continuous Torque	19.4 N·m	19.4 N·m
Peak Torque	41.0 N·m	48.6 N·m
Frame	165 mm	165 mm
Stack	101.6 mm	101.6 mm
Rotor Inertia	0.00147 kg·m²	0.00147 kg·m²
Application Focus	Higher torque at moderate speed	Higher-speed operation
Brake	24 V DC on MJ74AA	Configuration dependent

The B540K is the better choice when high motor speed is important.

The B540D is the better fit when 2000 rpm is sufficient and the machine is designed around a lower-speed, higher-torque operating point.

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26. B540D-MJ74AA vs. B520K

The B520K is a smaller-stack, higher-speed motor.

Parameter	MPL-B540D-MJ74AA	MPL-B520K
Speed	2000 rpm	4000 rpm
Power	3.4 kW	3.5 kW
Continuous Torque	19.4 N·m	10.7 N·m
Peak Torque	41.0 N·m	23.2 N·m
Rotor Inertia	0.00147 kg·m²	0.000783 kg·m²
Frame	165 mm	165 mm
Stack	101.6 mm	50.8 mm
Feedback	Multi-turn	Configuration dependent
Shaft	Keyed	Configuration dependent
Brake	24 V DC	Configuration dependent
Weight	Approx. 17.6 kg	Approx. 9.8 kg family value

This comparison makes the application distinction clear.

The B520K emphasizes high speed and low rotor inertia.

The B540D emphasizes higher torque and multi-turn positioning.

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27. Application Selection Table

Machine Requirement	Recommended Direction
High-speed 4000 rpm axis	MPL-B520K / B540K
2000 rpm medium-torque axis	MPL-B540D
Multi-turn absolute feedback	MPL-B540D-MJ series
Keyed shaft	MJ configuration
Keyless shaft	MK configuration
Integrated holding brake	74 configuration
No integrated brake	72 configuration
More than 19 N·m continuous torque	B560F or larger
Around 26.8 N·m continuous torque	MPL-B560F
Around 34 N·m continuous torque	MPL-B580F
Higher-speed B540-class motor	MPL-B540K

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28. Installation Considerations

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

The approximately 17.6 kg brake-equipped motor should be supported adequately during installation.

The mounting bolts should be appropriate for the machine structure and motor mounting requirements.

Shaft alignment is particularly important.

Incorrect coupling alignment can introduce additional radial and axial loads into the motor bearings.

This can result in increased vibration, higher operating temperature, coupling wear, or reduced motor service life.

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29. Coupling Considerations

Because the MPL-B540D-MJ74AA uses a keyed shaft, the coupling must be compatible with the shaft diameter and keyway.

The coupling should be selected based on:

• Continuous torque
• Peak torque
• Maximum speed
• Shaft diameter
• Key dimensions
• Radial load
• Axial load
• Misalignment tolerance
• Environmental conditions
• Required service life

A coupling that is acceptable for a small servo motor should not automatically be assumed suitable for a B540D motor.

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30. Brake Control Considerations

The integrated brake should be controlled according to the machine’s motion sequence.

A typical vertical-axis sequence may involve:

1. Servo system establishes control.
2. Motor produces sufficient holding torque.
3. Brake is released.
4. Axis begins motion.
5. Servo drive controls acceleration and deceleration.
6. Axis reaches the commanded position.
7. Servo torque is maintained.
8. Brake is applied when appropriate.
9. Servo torque is removed after the brake has engaged.

The exact sequence depends on the servo drive, machine architecture, safety system, and application requirements.

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31. Multi-Turn Feedback Applications

The multi-turn encoder makes the motor particularly suitable for mechanisms where one complete motor revolution is not enough to represent the machine’s entire travel range.

For example, consider a ball screw with a relatively small pitch.

A linear axis can move a considerable distance while the motor rotates through many revolutions.

A multi-turn absolute feedback system is well suited to this type of motion.

This is one of the major practical reasons to choose the MJ feedback configuration.

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32. CNC and Machine-Tool Applications

The motor can be used for various CNC and machine-tool axes.

Potential applications include:

• Feed axes
• Positioning axes
• Automatic tool mechanisms
• Rotary positioning
• Auxiliary axes
• Loading and unloading mechanisms

The 2000 rpm speed class is particularly suitable for mechanical systems where the transmission is optimized for moderate motor speed.

The integrated brake can also be useful for selected vertical machine axes.

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33. Packaging Applications

Packaging machinery often requires precise synchronization between multiple axes.

The MPL-B540D-MJ74AA can be considered for:

• Product indexing
• Film feeding
• Cutting
• Forming
• Product positioning
• Conveyor synchronization
• Rotary feeding
• Pick-and-place mechanisms

The multi-turn encoder is useful when the motor completes multiple revolutions during the normal operating cycle.

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34. Automated Assembly

Automated assembly machinery can require high repeatability and accurate positioning.

The motor can be used for:

• Screw-driving mechanisms
• Rotary positioning
• Component feeding
• Tool positioning
• Transfer mechanisms
• Assembly slides
• Indexing mechanisms

The 19.4 N·m continuous torque rating provides useful capacity for medium-duty servo axes.

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35. Material Handling and Lifting

The motor’s brake makes it particularly relevant to lifting and vertical positioning applications.

Possible applications include:

• Vertical transfer axes
• Lifting platforms
• Vertical slides
• Automated storage equipment
• Transfer mechanisms
• Gravity-loaded positioning systems

For lifting applications, the brake, mechanical transmission, load inertia, and safety system must all be considered together.

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36. Maintenance and Service

Routine inspection should cover the complete servo axis.

Important inspection points include:

• Mounting bolts
• Shaft coupling
• Shaft key
• Keyway
• Motor bearings
• Connector condition
• Power cable
• Feedback cable
• Brake wiring
• Brake operation
• Motor temperature
• Abnormal vibration
• Servo following error
• Encoder feedback
• Mechanical backlash
• Machine alignment

If the motor begins producing unusual noise or vibration, the problem should not automatically be assumed to be an electrical motor failure.

Mechanical alignment, coupling wear, bearing condition, cable problems, feedback problems, drive tuning, and load changes can all affect servo performance.

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37. Replacement Considerations

When replacing an existing servo motor with MPL-B540D-MJ74AA, the complete model configuration should be checked.

Replacement Item	Required Specification
Model	MPL-B540D-MJ74AA
Voltage	460 V class
Speed	2000 rpm
Power	3.4 kW
Continuous Torque	19.4 N·m
Peak Torque	41.0 N·m
Feedback	Multi-turn absolute
Shaft	Keyed
Brake	24 V DC
Frame	165 mm
Stack	101.6 mm
Connector	SpeedTEC DIN right-angle
Connector Rotation	180°
Mounting	IEC metric
Approx. Weight	17.6 kg
Shaft Seal	None
Full Dimensions	Verify mechanical drawing

A replacement motor should not be selected solely because the nominal power and frame size appear similar.

Feedback type, brake, shaft configuration, connector, mounting pattern, shaft projection, and overall mechanical envelope all need to be checked.

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38. Product Advantages at a Glance

Advantage	Description
High Continuous Torque	19.4 N·m continuous stall torque
High Peak Torque	41.0 N·m peak stall torque
3.4 kW Output	Suitable for medium-duty industrial motion
2000 rpm Speed	Balanced torque and speed characteristics
Multi-Turn Feedback	Suitable for multi-revolution positioning
Absolute Feedback	Useful for precise position management
Keyed Shaft	Conventional mechanical transmission interface
24 V DC Brake	Integrated holding capability
Low Inertia	Responsive servo dynamics
165 mm Frame	Compact industrial motor class
101.6 mm Stack	Higher torque than shorter-stack B520K
Right-Angle Connector	Convenient cable routing
180° Rotatable Connector	Flexible installation
IEC Metric Mounting	Practical machine integration

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39. Complete Product Specification

Category	Specification
Model	MPL-B540D-MJ74AA
Brand	Allen-Bradley
Series	MPL Series
Product Family	MP-Series Low-Inertia Servo Motors
Motor Type	Brushless AC rotary servo motor
Voltage Class	460 V
System Voltage	480 V AC
Rated Power	3.4 kW
Rated Speed	2000 rpm
Maximum Speed	2000 rpm
Continuous Stall Torque	19.4 N·m
Peak Stall Torque	41.0 N·m
Rotor Inertia	Approx. 0.00147 kg·m²
Continuous Stall Current	Approx. 10.5 A
Peak Stall Current	Approx. 23.0 A
Frame Size	165 mm
Frame Size, Imperial	6.50 in
Magnetic Stack	101.6 mm
Stack Length, Imperial	4.0 in
Feedback	Multi-turn high-resolution absolute encoder
Feedback Resolution	1024 cycles/rev Sin/Cos
Feedback Protocol	Hiperface
Shaft	Keyed shaft extension
Shaft Key	Yes
Shaft Seal	No
Brake	24 V DC holding brake
Connector	SpeedTEC DIN
Connector Orientation	Right-angle
Connector Rotation	180° rotatable
Mounting	IEC metric
Mounting Holes	Free mounting holes / Type FF
Operating Temperature	Up to approximately 40 °C
Approx. Weight	17.6 kg
Base B540D Family Weight	Approx. 15 kg
Overall Dimensions	Verify exact mechanical drawing
Typical Applications	CNC, packaging, assembly, material handling, indexing, positioning
Main Strength	Torque + multi-turn feedback + integrated brake

The exact configuration is identified as a 460 V-class, 165 mm-frame, 101.6 mm-stack, 2000 rpm motor with multi-turn absolute feedback, keyed shaft, SpeedTEC DIN right-angle connector, and 24 V DC brake.

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40. Final Conclusion

The MPL-B540D-MJ74AA is a well-balanced industrial servo motor for applications that require considerably more torque than a smaller high-speed servo while still maintaining a relatively compact 165 mm frame.

Its main technical characteristics are 3.4 kW rated output, 2000 rpm rated speed, 19.4 N·m continuous stall torque, approximately 41.0 N·m peak stall torque, approximately 0.00147 kg·m² rotor inertia, 165 mm frame size, 101.6 mm magnetic stack, multi-turn high-resolution absolute feedback, keyed shaft construction, and an integrated 24 V DC holding brake.

The multi-turn absolute encoder is particularly valuable for machine axes that rotate through multiple motor revolutions.

For example, ball-screw-driven linear axes, long-travel positioning systems, rotary indexing equipment, and automated machinery can benefit from this feedback arrangement.

The keyed shaft provides a familiar mechanical interface and is convenient for machines using conventional keyed couplings, gears, pulleys, and other transmission components.

The integrated 24 V DC brake is another major advantage.

Compared with the MJ72AA version, the MJ74AA provides motor-mounted holding capability, making it more attractive for vertical axes, gravity-loaded mechanisms, lifting equipment, and machines that need a defined mechanical holding condition when servo torque is removed.

The 2000 rpm speed class also gives this motor a different application profile from the 4000 rpm B520K and B540K motors.

Where the B520K is more focused on high speed and low rotor inertia, the B540D provides a stronger continuous torque capability and is better suited to applications where torque and multi-revolution positioning are the primary requirements.

When additional torque is required, the B560F and B580F families provide higher continuous and peak torque.

When higher shaft speed is required, the B540K provides a natural higher-speed alternative.

Overall, the MPL-B540D-MJ74AA is particularly well suited to industrial machines requiring medium-power servo performance, strong continuous torque, multi-turn absolute position feedback, a conventional keyed shaft, and integrated 24 V DC mechanical holding.

For product selection, the most important points to verify are the 2000 rpm speed requirement, 3.4 kW power class, 19.4 N·m continuous torque, 41.0 N·m peak torque, multi-turn feedback, keyed shaft, 24 V DC brake, 165 mm frame, 101.6 mm stack, approximately 17.6 kg configured weight, and the exact mechanical envelope required by the machine.