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MPL-B540D-SJ74AA Low-Inertia Servo Motor – Detailed Product Introduction and Technical Guide

1. Product Overview

The MPL-B540D-SJ74AA is a low-inertia brushless AC rotary servo motor from the MP-Series MPL product family. It is designed for industrial motion-control systems that require accurate positioning, controlled acceleration and deceleration, stable torque output, and reliable high-resolution feedback.

This model uses a 460 V electrical class, a 165 mm frame size, a 101.6 mm magnet stack, and a 2000 rpm rated speed. It is configured with a single-turn high-resolution encoder, keyed shaft extension, right-angle SpeedTEC DIN connector, and an integrated 24 V DC holding brake.

The motor belongs to the low-inertia section of the MPL family. Its design is intended for machine axes that repeatedly accelerate, decelerate, stop, reverse, and reposition. This makes the motor well suited to automated machinery where response time and positioning accuracy are more important than simply achieving maximum rotational speed.

The MPL-B540D-SJ74AA is especially useful where a holding brake is required. Compared with the closely related SJ72AA configuration, the SJ74AA includes a 24 V DC brake, making it more suitable for vertical axes, gravity-loaded mechanisms, and applications where the load needs to remain mechanically held when servo torque is removed.

2. Brand and Product Series

Item	Specification
Brand	Allen-Bradley
Product family	MP-Series
Servo series	MPL Series
Product type	Low-Inertia Brushless AC Servo Motor
Model	MPL-B540D-SJ74AA
Voltage class	460 V
AC supply designation	480 V AC
Frame size	165 mm
Magnet stack	101.6 mm
Rated speed	2000 rpm
Feedback	Single-turn high-resolution encoder
Shaft	Keyed shaft extension
Brake	24 V DC holding brake
Connector	SpeedTEC DIN, right-angle
Connector rotation	180° rotatable
Mounting	IEC metric
Mounting holes	Free mounting holes, Type FF
Product status	Active

The model description identifies the motor as a 460 V, 165 mm-frame, 101.6 mm-stack, 2000 rpm servo motor with a single-turn high-resolution encoder, keyed shaft, SpeedTEC DIN connector, and 24 V DC brake.

3. Understanding the Model Number

The model number MPL-B540D-SJ74AA contains useful information about the motor configuration.

Model Code	General Meaning
MPL	MPL low-inertia brushless servo motor family
B	460 V electrical class
540	Frame/stack family
D	2000 rpm motor-speed configuration
S	Single-turn high-resolution encoder
J	Keyed shaft extension
7	SpeedTEC DIN connector
4	24 V DC brake
AA	Configuration/revision designation

This coding structure is particularly useful when comparing motors within the same family.

For example, the difference between SJ72AA and SJ74AA is primarily the brake configuration. The SJ72AA has no brake, while the SJ74AA includes the 24 V DC brake.

Likewise, the difference between the S and M feedback designations is important. The S configuration uses a single-turn high-resolution encoder, whereas M configurations use multi-turn high-resolution absolute feedback. Therefore, a motor that looks mechanically similar is not necessarily an electrically interchangeable replacement.

4. Main Technical Parameters

Parameter	Specification
Model	MPL-B540D-SJ74AA
Motor type	Brushless AC rotary servo motor
Servo family	MP-Series MPL
Electrical class	460 V
AC designation	480 V AC
Rated speed	2000 rpm
Rated power	Approximately 3.4 kW
Continuous stall torque	Approximately 19.4 N·m
Peak stall torque	Approximately 41.0 N·m
Rotor inertia	Approximately 0.00147 kg·m²
Feedback	Single-turn high-resolution 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
Frame size	165 mm
Magnet stack	101.6 mm
Approximate net weight	About 15 kg class; brake-equipped configuration should be checked against the exact mechanical documentation
Overall dimensions	Use the exact mechanical drawing for final L × W × H installation dimensions

The B540D motor family is rated at approximately 2000 rpm, 3.4 kW, 19.4 N·m continuous stall torque, and 41.0 N·m peak stall torque. The listed rotor inertia is approximately 0.00147 kg·m².

5. Dimensions and Weight

The principal mechanical dimensions associated with this model are the 165 mm frame size and 101.6 mm magnet stack length.

The 165 mm frame corresponds to approximately 6.50 inches, while the 101.6 mm stack corresponds to approximately 4.00 inches. These dimensions identify the basic mechanical size of the motor and are particularly important when checking compatibility with an existing machine.

Mechanical Parameter	Specification
Frame size	165 mm / 6.50 in
Magnet stack length	101.6 mm / 4.00 in
Mounting standard	IEC metric
Mounting-hole arrangement	Free mounting holes, Type FF
Shaft	Keyed shaft extension
Connector	Right-angle SpeedTEC DIN
Connector rotation	180°
Brake	Integrated 24 V DC brake
Overall L × W × H	Verify from exact mechanical drawing
Approximate family net weight	15 kg class
Weight for engineering/layout use	Verify exact brake-equipped configuration

The 15 kg value is associated with the B540D motor family in published technical tables. Brake-equipped versions can have a different net mass because the brake adds mechanical components, so the exact SJ74AA weight should be confirmed against the specific mechanical documentation before final shipping, lifting, or machine-frame calculations.

For practical machine design, the frame size and stack length should not be treated as the complete outside envelope. Cable connectors, shaft extension, brake housing, mounting features, and cable-bend radius can all affect the actual space required.

6. Electrical Characteristics

The MPL-B540D-SJ74AA belongs to the 460 V electrical class and is identified as a 480 V AC rotary servo motor configuration.

This voltage class is intended for industrial servo systems using a compatible high-voltage servo drive. The motor should therefore be matched to the correct servo amplifier, feedback interface, motor cable, and system configuration.

Electrical Parameter	Specification
Electrical class	460 V
AC designation	480 V AC
Rated speed	2000 rpm
Rated power	Approx. 3.4 kW
Continuous stall torque	Approx. 19.4 N·m
Peak stall torque	Approx. 41.0 N·m
Continuous stall current	Approx. 10.5 A
Peak stall current	Approx. 23.0 A
Feedback	Single-turn high-resolution encoder
Brake supply	24 V DC
Brake	Holding brake

The published B540D family data lists approximately 10.5 A continuous stall current and 23.0 A peak stall current, together with 19.4 N·m continuous stall torque and 41.0 N·m peak stall torque.

7. Speed and Torque

The rated speed of the MPL-B540D-SJ74AA is 2000 rpm.

A 2000 rpm servo motor is often useful when the machine needs a combination of substantial torque and controlled rotational speed. It is not optimized simply for very high rpm; instead, the B540D configuration provides a comparatively strong torque capability within its frame and power class.

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

Performance Parameter	Value
Rated speed	2000 rpm
Rated power	3.4 kW
Continuous stall torque	19.4 N·m
Peak stall torque	41.0 N·m
Rotor inertia	0.00147 kg·m²
Continuous stall current	10.5 A
Peak stall current	23.0 A

The continuous torque figure is particularly important for determining whether the motor can handle the thermal load during normal operation.

Peak torque is more relevant to short-duration acceleration, deceleration, indexing, and transient load conditions.

For actual motor sizing, the complete machine duty cycle should be considered rather than selecting the motor from the peak torque value alone.

8. Feedback System

The MPL-B540D-SJ74AA uses a single-turn high-resolution encoder.

The encoder provides motor-position feedback to the servo control system. This allows the drive to regulate speed, torque, and position with the precision expected from a servo motor.

The single-turn configuration is particularly relevant when comparing this model with the multi-turn versions of the same B540D family.

Feedback Parameter	Specification
Feedback type	Single-turn high-resolution encoder
Feedback category	High-resolution servo feedback
Position information	Single-turn
Application	Precision servo positioning
Main benefit	Accurate speed and position feedback
Replacement consideration	Feedback type must match the compatible drive/control configuration

When replacing an existing motor, it is important to verify the feedback type. A mechanically compatible motor with a different encoder arrangement may not be a plug-and-play replacement.

9. 24 V DC Holding Brake

The integrated 24 V DC brake is one of the main features that distinguishes the SJ74AA configuration.

The brake is useful when the machine needs the motor shaft to remain mechanically held after servo torque is removed.

Typical examples include vertical axes, lifting mechanisms, Z-axis applications, and machinery where the driven load could move under gravity.

Brake Parameter	Specification
Brake	Integrated holding brake
Brake voltage	24 V DC
Brake type	Holding brake
Main purpose	Hold motor shaft/load when servo torque is removed
Typical application	Vertical axes and gravity-loaded mechanisms
Control requirement	Compatible 24 V DC brake control circuit

The brake should not normally be treated as a substitute for a properly designed machine safety system. In applications involving suspended or hazardous loads, additional mechanical safety provisions may be required.

10. Shaft Configuration

The motor uses a keyed shaft extension.

The keyed shaft provides a conventional positive mechanical connection between the servo motor and the driven mechanism.

Shaft Parameter	Specification
Shaft type	Keyed shaft extension
Keyway	Yes
Mechanical connection	Keyed coupling/transmission
Typical use	Couplings, gearboxes, ball screws, pulleys
Alignment	Required
Servo coupling	Recommended where applicable

The coupling must be selected according to motor torque, peak torque, rotational speed, shaft size, torsional stiffness, and allowable misalignment.

11. Connector Design

The MPL-B540D-SJ74AA uses a SpeedTEC DIN connector in a right-angle configuration.

The connector is designed to provide a practical connection arrangement for industrial machinery.

The connector is also described as 180° rotatable, which can make installation easier where machine covers, cable tracks, guarding, or adjacent components limit cable-routing space.

Connector Parameter	Specification
Connector type	SpeedTEC DIN
Orientation	Right angle
Rotation	180° rotatable
Connection style	Quick-connect arrangement
Main advantage	Flexible cable routing
Installation consideration	Maintain appropriate cable bend radius

Cable routing should avoid excessive bending, twisting, pulling, or vibration at the connector.

12. Product Advantages

12.1 Low-Inertia Servo Design

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

Low rotor inertia helps the motor respond quickly when the control system commands a change in speed or position.

This is especially useful in applications with frequent acceleration, deceleration, indexing, and direction changes.

12.2 Strong Torque Capability

The B540D configuration provides approximately 19.4 N·m continuous stall torque and 41.0 N·m peak stall torque.

This gives the motor useful torque capacity for medium-duty industrial positioning systems.

12.3 Integrated Holding Brake

The 24 V DC brake is a major advantage where the load needs to remain stationary after the servo motor is disabled.

For vertical positioning axes, this can be particularly useful because the brake can provide mechanical holding rather than relying entirely on continuous servo torque.

12.4 High-Resolution Feedback

The single-turn high-resolution encoder supports precise control of motor position and speed.

This makes the motor appropriate for positioning systems where repeatability and controlled movement are important.

12.5 Keyed Shaft

The keyed shaft provides a familiar mechanical interface.

It can be integrated with many conventional industrial transmission arrangements when the coupling and shaft dimensions are correctly matched.

12.6 Right-Angle Connector

The right-angle connector helps keep the motor cable close to the machine structure.

This can be beneficial in compact machine designs.

12.7 180° Connector Rotation

The rotatable connector provides additional installation flexibility.

This is useful when the motor is installed inside a crowded machine frame and cable routing cannot be arranged directly behind the motor.

12.8 Balanced Speed and Torque

The 2000 rpm speed rating and approximately 19.4 N·m continuous torque make this model a balanced choice for applications that need more torque than a high-speed, lower-torque servo configuration.

13. Typical Applications

CNC Machinery

The MPL-B540D-SJ74AA can be used for controlled positioning axes in CNC and machine-tool applications.

The high-resolution encoder provides feedback for accurate motion control, while the brake can be advantageous for vertical machine axes.

Vertical Linear Axes

One of the most natural applications for a brake-equipped servo motor is a vertical linear axis.

A ball screw or similar transmission can convert the motor’s rotary motion into controlled vertical movement.

The brake provides an additional holding function when the servo is disabled.

Packaging Machinery

Packaging machines often require repeated acceleration, deceleration, indexing, cutting, feeding, and positioning.

The low-inertia design can help the axis respond efficiently to repeated motion commands.

Assembly Equipment

Automated assembly systems often need precise positioning of tools, fixtures, slides, and rotary mechanisms.

The servo motor’s high-resolution feedback is well suited to such controlled motion.

Material Handling

The motor can be used for automated transfer systems, conveyors, positioning units, and other controlled mechanical movements.

Where a vertical or gravity-loaded mechanism is involved, the brake option can be particularly valuable.

Rotary Indexing Systems

Servo motors are widely used in rotary indexing applications where the mechanism must repeatedly move to defined positions.

The B540D’s torque and speed characteristics can be appropriate for medium-sized indexing mechanisms when the load is correctly calculated.

Ball-Screw Applications

The motor can be connected to a ball screw through a suitable precision coupling.

This configuration is commonly used for linear positioning axes in industrial machinery.

Automated Production Lines

The motor can serve as one axis within a multi-axis automated production machine.

Its 2000 rpm speed and moderate-to-high torque capability provide a useful combination for many machine movements.

14. Application Benefits

The biggest practical benefit of the MPL-B540D-SJ74AA is the combination of servo positioning capability and a built-in holding brake.

A standard no-brake motor may be suitable for a horizontal axis, but a vertical axis can require a different configuration.

The SJ74AA provides the same general B540D motor platform while adding the 24 V DC brake.

This makes it particularly useful when the machine needs to maintain position after servo power is removed.

Another advantage is the keyed shaft. The mechanical interface is familiar to machine designers and maintenance personnel, reducing the need for unusual transmission components.

15. Closely Related Models

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

Model	Speed	Power	Continuous Torque	Peak Torque	Feedback	Brake	Frame / Stack
MPL-B540D-SJ72AA	2000 rpm	3.4 kW	19.4 N·m	41.0 N·m	Single-turn	No	165 / 101.6 mm
MPL-B540D-SJ74AA	2000 rpm	3.4 kW	19.4 N·m	41.0 N·m	Single-turn	24 V DC	165 / 101.6 mm
MPL-B540D-MJ72AA	2000 rpm	3.4 kW	19.4 N·m	41.0 N·m	Multi-turn absolute	No	165 / 101.6 mm
MPL-B540D-MJ74AA	2000 rpm	3.4 kW	19.4 N·m	41.0 N·m	Multi-turn absolute	24 V DC	165 / 101.6 mm
MPL-B540K-SJ74AA	4000 rpm	5.4 kW	19.4 N·m	48.6 N·m	Single-turn	24 V DC	165 / 101.6 mm

The B540D variants are particularly close because they retain the same basic frame and stack dimensions while changing feedback and brake configurations. The B540K configuration moves to a 4000 rpm class and higher power. The product-family listings identify both the single-turn and multi-turn B540D configurations as well as the B540K configurations.

16. Five Recommended Related Models

1. MPL-B540D-SJ72AA

This is the closest comparison to the target model.

It uses the same general B540D motor configuration but does not include the 24 V DC brake.

It is therefore suitable for applications where the machine does not require a dedicated motor holding brake.

2. MPL-B540D-MJ72AA

This model maintains the B540D family and keyed-shaft configuration but uses multi-turn high-resolution absolute feedback.

It is useful when the control architecture requires multi-turn position information.

3. MPL-B540D-MJ74AA

This is one of the closest alternatives to the target motor.

It combines the B540D mechanical platform with multi-turn high-resolution feedback and a 24 V DC brake.

It is a useful option when both absolute multi-turn feedback and mechanical holding are required.

4. MPL-B540K-SJ74AA

This configuration moves from the 2000 rpm B540D class to the 4000 rpm B540K class while retaining a single-turn feedback configuration and brake option.

It is worth considering when the application requires greater rotational speed.

5. MPL-B560F-MJ74AA

This model moves to the longer B560F stack and a 3000 rpm motor class.

The B560F family provides higher torque and power capability than the B540D family, making it appropriate for applications where the B540D is approaching its load limit.

17. Five Same-Brand Popular/Important Comparison Models

Model	Rated Speed	Rated Power	Continuous Torque	Peak Torque	Rotor Inertia	Approx. Weight	Frame / Stack
MPL-B520K	4000 rpm	3.5 kW	10.7 N·m	23.2 N·m	0.000783 kg·m²	9.8 kg	165 / 50.8 mm
MPL-B540D	2000 rpm	3.4 kW	19.4 N·m	41.0 N·m	0.00147 kg·m²	15.0 kg	165 / 101.6 mm
MPL-B540K	4000 rpm	5.4 kW	19.4 N·m	48.6 N·m	0.00147 kg·m²	Not listed in the same family table	165 / 101.6 mm
MPL-B560F	3000 rpm	5.5 kW	26.8 N·m	67.8 N·m	0.00213 kg·m²	20.2 kg	165 / 152.4 mm
MPL-B580F	3000 rpm	7.1 kW	34.0 N·m	87.0 N·m	0.00289 kg·m²	25.4 kg	165 / 203.2 mm

These models cover a useful range from relatively compact high-speed motors to larger, higher-torque configurations. The published family data lists 3.5 kW for the B520K, 3.4 kW for the B540D, 5.4 kW for the B540K, 5.5 kW for the B560F, and 7.1 kW for the B580F.

18. Model Selection Comparison

Model	Best Suited For	Main Advantage
MPL-B520K	Higher-speed, lower-torque axes	4000 rpm operation with lower inertia
MPL-B540D	General 2000 rpm servo applications	Strong balance of torque and speed
MPL-B540K	Higher-speed B540-class applications	4000 rpm and higher power
MPL-B560F	Higher-load applications	More continuous and peak torque
MPL-B580F	Heavy-duty servo axes	Higher power and torque capacity

The correct selection should be based on the complete load profile, including acceleration, deceleration, duty cycle, speed, reflected inertia, mechanical transmission ratio, and continuous thermal loading.

19. SJ72AA Versus SJ74AA

The most important difference between the two models is the brake.

Feature	MPL-B540D-SJ72AA	MPL-B540D-SJ74AA
Rated speed	2000 rpm	2000 rpm
Rated power	Approx. 3.4 kW	Approx. 3.4 kW
Frame	165 mm	165 mm
Stack	101.6 mm	101.6 mm
Feedback	Single-turn high-resolution	Single-turn high-resolution
Shaft	Keyed	Keyed
Connector	SpeedTEC DIN	SpeedTEC DIN
Brake	None	24 V DC
Continuous torque	Approx. 19.4 N·m	Approx. 19.4 N·m
Peak torque	Approx. 41.0 N·m	Approx. 41.0 N·m

The SJ74AA should be selected when the holding-brake function is needed.

The SJ72AA is more appropriate when the machine does not require an integrated motor brake.

20. SJ74AA Versus MJ74AA

Another important comparison is between the single-turn and multi-turn feedback configurations.

Feature	MPL-B540D-SJ74AA	MPL-B540D-MJ74AA
Rated speed	2000 rpm	2000 rpm
Frame	165 mm	165 mm
Stack	101.6 mm	101.6 mm
Feedback	Single-turn high-resolution	Multi-turn high-resolution absolute
Shaft	Keyed	Keyed
Brake	24 V DC	24 V DC
Motor family	B540D	B540D
Typical reason for selection	Standard servo positioning with brake	Absolute multi-turn positioning with brake

The mechanical similarity between these models should not be confused with electrical interchangeability.

The feedback architecture needs to be compatible with the servo drive and control system.

21. Brake Applications

A brake-equipped servo motor is particularly useful for vertical motion.

Consider a vertical ball-screw axis carrying a load. When the servo drive is powered and actively controlling the motor, the motor can maintain position using servo torque.

If power is removed, however, the mechanical load may move under gravity.

The integrated 24 V DC holding brake provides a mechanical holding function for this type of application.

Typical examples include:

• Vertical CNC axes.
• Z-axis positioning.
• Lifting equipment.
• Vertical transfer mechanisms.
• Pick-and-place systems with vertical travel.
• Elevating platforms.
• Gravity-loaded machine mechanisms.

The brake should always be incorporated into the machine’s overall safety and control design rather than treated as the only safety device.

22. Low-Inertia Performance

Low rotor inertia is one of the important characteristics of the MPL family.

When a servo motor accelerates, part of the available motor torque is used to accelerate the rotor itself.

A lower rotor inertia can reduce the amount of torque required to accelerate the motor rotor and can help the control system achieve rapid changes in speed.

This is useful in applications where the machine repeatedly starts, stops, indexes, or reverses.

23. Torque and Inertia Relationship

The B540D family has approximately 0.00147 kg·m² rotor inertia.

For machine design, the motor’s rotor inertia should be considered together with the reflected load inertia.

A motor can perform well with one mechanical load but poorly with another if the reflected inertia is significantly different.

For this reason, servo selection should consider:

• Motor rotor inertia.
• Load inertia.
• Gear ratio.
• Ball-screw pitch.
• Acceleration time.
• Deceleration time.
• Required positioning accuracy.
• Duty cycle.
• Continuous torque.
• Peak torque.

24. Installation Recommendations

The motor should be mounted on a rigid machine structure with a suitable mounting surface.

The mounting surface should be clean and properly aligned.

The motor shaft should be aligned with the driven equipment according to the coupling manufacturer’s allowable limits.

The motor should not be used to compensate for severe mechanical misalignment.

Incorrect alignment can produce excessive radial or axial forces, increase vibration, and shorten bearing life.

25. Coupling Selection

For a ball screw or gearbox application, a precision servo coupling is normally preferred.

The coupling should have sufficient torque capacity and speed rating for the application.

Important parameters include:

• Maximum rotational speed.
• Continuous torque.
• Peak torque.
• Shaft diameter.
• Torsional stiffness.
• Radial misalignment.
• Angular misalignment.
• Axial movement.
• Operating temperature.

The coupling should be installed according to the manufacturer’s recommended procedure.

26. Cable Routing

The right-angle SpeedTEC DIN connector provides a practical arrangement for machine cable routing.

However, the cable should not be pulled directly from the connector.

The cable should have appropriate strain relief and bend radius.

In moving-machine applications, the motor cable should also be selected for the required flexing environment.

27. Maintenance Considerations

The motor itself is generally a low-maintenance component, but regular inspection of the complete motion system is recommended.

Maintenance personnel should check:

• Motor mounting hardware.
• Coupling condition.
• Shaft alignment.
• Motor cable.
• Connector condition.
• Brake operation.
• Abnormal vibration.
• Bearing noise.
• Motor temperature.
• Encoder feedback stability.
• Mechanical backlash.

The integrated brake should receive particular attention in vertical-axis applications.

A brake that does not release correctly can generate unnecessary heat and mechanical loading.

A brake that does not hold correctly can create a serious machine-control problem.

28. Advantages for Machine Builders

For machine builders, the MPL-B540D-SJ74AA offers a practical combination of:

• 2000 rpm speed.
• Approximately 3.4 kW power.
• Approximately 19.4 N·m continuous torque.
• Approximately 41.0 N·m peak torque.
• Single-turn high-resolution feedback.
• Keyed shaft.
• Integrated 24 V DC brake.
• 165 mm frame.
• 101.6 mm stack.
• Right-angle rotatable connector.

This combination gives designers a broad range of options for machine-axis applications.

29. Advantages for Maintenance and Replacement

The model number provides useful information for identifying the motor configuration.

When replacing a damaged motor, technicians can compare:

• Frame size.
• Stack length.
• Speed.
• Feedback.
• Shaft.
• Connector.
• Brake.
• Voltage class.

This reduces the risk of choosing a mechanically similar motor with an incompatible feedback or brake configuration.

30. Important Replacement Checks

Before replacing an MPL-B540D-SJ74AA, the following points should be checked.

Check Item	What to Verify
Model	Exact motor catalog number
Voltage	460 V class / 480 V AC system compatibility
Speed	2000 rpm
Power	Approximately 3.4 kW
Feedback	Single-turn high-resolution encoder
Shaft	Keyed shaft
Brake	24 V DC brake
Connector	SpeedTEC DIN right-angle
Frame	165 mm
Stack	101.6 mm
Mounting	IEC metric
Mechanical envelope	Exact drawing
Weight	Exact brake-equipped motor weight
Drive compatibility	Correct servo drive configuration
Cable	Correct motor/feedback cable arrangement

A replacement should not be selected only because the motor looks the same externally.

31. Detailed Parameter Table

Category	Parameter	MPL-B540D-SJ74AA
Identification	Model	MPL-B540D-SJ74AA
Identification	Product family	MP-Series MPL
Identification	Motor type	Low-Inertia Brushless AC Servo Motor
Electrical	Voltage class	460 V
Electrical	AC designation	480 V AC
Performance	Rated speed	2000 rpm
Performance	Rated power	Approx. 3.4 kW
Performance	Continuous stall torque	Approx. 19.4 N·m
Performance	Peak stall torque	Approx. 41.0 N·m
Performance	Continuous stall current	Approx. 10.5 A
Performance	Peak stall current	Approx. 23.0 A
Rotor	Rotor inertia	Approx. 0.00147 kg·m²
Feedback	Feedback type	Single-turn high-resolution encoder
Shaft	Shaft configuration	Keyed shaft extension
Brake	Brake	24 V DC holding brake
Connector	Connector type	SpeedTEC DIN
Connector	Orientation	Right angle
Connector	Rotation	180° rotatable
Mechanical	Frame size	165 mm / 6.50 in
Mechanical	Magnet stack	101.6 mm / 4.00 in
Mechanical	Mounting	IEC metric
Mechanical	Mounting holes	Free mounting holes, Type FF
Mechanical	Overall dimensions	Verify exact mechanical drawing
Weight	Approximate family weight	15 kg class
Weight	Exact SJ74AA weight	Verify brake-equipped mechanical documentation
Application	Typical use	Industrial servo motion control
Application	Common machines	CNC, packaging, assembly, indexing, vertical axes, material handling

The principal B540D performance values are supported by the published MPL family data, while the exact SJ74AA configuration is identified as the 460 V, 165 mm, 101.6 mm, 2000 rpm, single-turn, keyed-shaft, 24 V brake configuration.

32. Summary of Main Advantages

Advantage	Practical Meaning
Low inertia	Good dynamic response
2000 rpm	Balanced speed and torque
3.4 kW	Suitable for medium-power motion axes
19.4 N·m continuous torque	Good continuous load capability
41.0 N·m peak torque	Supports short-duration acceleration loads
High-resolution feedback	Accurate servo control
Single-turn encoder	Suitable for conventional precision positioning
Keyed shaft	Simple and familiar mechanical interface
24 V DC brake	Useful for vertical and gravity-loaded axes
Right-angle connector	Convenient cable routing
180° connector rotation	Flexible installation
165 mm frame	Established industrial motor size
101.6 mm stack	B540D torque/power configuration

33. Overall Product Assessment

The MPL-B540D-SJ74AA is a well-balanced low-inertia servo motor for industrial machinery requiring approximately 3.4 kW of motor power, 2000 rpm operation, high-resolution single-turn feedback, and an integrated 24 V DC holding brake.

Its approximately 19.4 N·m continuous torque and 41.0 N·m peak torque give the B540D family a useful combination of torque and speed for many medium-duty motion applications.

The most important feature separating this model from the closely related SJ72AA configuration is the integrated brake.

That makes the SJ74AA especially attractive for vertical axes, lifting mechanisms, gravity-loaded positioning systems, and machines where the motor shaft needs to remain mechanically held after servo torque is removed.

The 165 mm frame and 101.6 mm stack establish the main mechanical size, while the keyed shaft provides a conventional mechanical interface.

The single-turn high-resolution encoder makes the motor appropriate for precision servo positioning where multi-turn absolute feedback is not required.

For higher-speed applications, the B540K family provides 4000 rpm configurations.

For applications requiring more torque, the B560F and B580F families provide larger stack lengths and greater torque capacity.

Overall, the MPL-B540D-SJ74AA is best characterized as a 2000 rpm, approximately 3.4 kW, 165 mm-frame, 101.6 mm-stack, low-inertia servo motor with single-turn high-resolution feedback, keyed shaft, right-angle rotatable connector, and integrated 24 V DC holding brake.

For a machine requiring these particular characteristics, it represents a well-defined servo configuration that combines dynamic response, useful torque capacity, precise feedback, and mechanical holding capability.