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Allen-Bradley MPL-B4540F-RK74AA Low-Inertia Servo Motor

1. Product Overview

The Allen-Bradley MPL-B4540F-RK74AA is a low-inertia brushless AC rotary servo motor designed for industrial motion-control applications requiring accurate positioning, rapid acceleration and deceleration, stable speed control, and reliable closed-loop operation.

This model belongs to the MP-Series MPL Low-Inertia Servo Motor Series and uses a 130 mm frame size with a 101.6 mm magnet stack. It operates in the 460 V AC / 480 V AC class and is rated for a maximum speed of approximately 3000 rpm.

The motor provides approximately 10.2 N·m of continuous torque and approximately 27.1 N·m of peak torque, placing it in the approximately 2.6 kW performance class.

The RK74AA configuration combines several important features: resolver feedback, a keyless shaft, a 24 V DC holding brake, a right-angle SpeedTEC DIN connector, 180° connector rotation, and IEC metric mounting.

The keyless shaft is particularly useful for mechanical systems that use clamping hubs, friction-lock couplings, shrink-fit connections, or other transmission arrangements where a conventional shaft key is not required.

The integrated 24 V DC brake makes this configuration especially suitable for applications where the motor shaft must be held when the servo system is disabled.

The motor is therefore well suited to a wide range of automated machinery, including positioning systems, packaging equipment, material-handling machines, indexing systems, assembly equipment, machine tools, and selected vertical-axis applications.

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2. Brand and Product Series

Item	Specification
Brand	Allen-Bradley
Product Family	MP-Series
Product Series	MPL Low-Inertia Servo Motor Series
Product Type	Brushless AC Rotary Servo Motor
Model	MPL-B4540F-RK74AA
Motor Technology	Permanent-Magnet Servo Motor
Motor Construction	Low-Inertia
Voltage Class	460 V AC
Application Voltage Class	480 V AC
Rated Speed	3000 rpm
Feedback	Resolver
Shaft Configuration	Keyless Shaft
Brake	24 V DC Holding Brake
Connector	SpeedTEC DIN
Connector Style	Right Angle
Connector Rotation	180° Rotatable
Mounting	IEC Metric
Frame Size	130 mm
Magnet Stack	101.6 mm

The MPL-B4540F-RK74AA is part of the MPL low-inertia servo motor family, which is intended for demanding industrial motion-control applications.

The B4540F configuration represents the motor’s frame and stack combination, while the RK74AA suffix identifies the feedback, shaft, connector, and brake configuration.

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3. Detailed Technical Parameters

Parameter	Specification
Model	MPL-B4540F-RK74AA
Brand	Allen-Bradley
Product Family	MP-Series
Product Series	MPL Low-Inertia Servo Motor
Motor Type	Brushless AC Rotary Servo Motor
Motor Design	Low-Inertia
Voltage	460 V AC
Application Voltage	480 V AC class
Phase	3-phase motor system
Speed	3000 rpm maximum class
Continuous Torque	Approx. 10.2 N·m
Peak Torque	Approx. 27.1 N·m
Rated Power	Approx. 2.6 kW
Feedback	2-Pole Resolver
Shaft	Keyless Shaft Extension
Shaft Key	None
Brake	24 V DC Holding Brake
Connector	SpeedTEC DIN Connector
Connector Position	Right Angle
Connector Rotation	180° Rotatable
Mounting	IEC Metric Flange
Mounting Hole Type	Free Mounting Holes, Type FF
Frame Size	130 mm
Frame Size in Inches	Approx. 5.12 in.
Magnet Stack	101.6 mm
Stack Length in Inches	Approx. 4.00 in.
Overall Length	Approx. 330 mm class
Weight	Approx. 9.1 kg
Feedback Technology	Resolver
Brake Voltage	24 V DC
Brake Configuration	Integrated Holding Brake
Shaft Configuration	Keyless
Connector Configuration	Right-Angle Quick-Connect Type
Duty Application	Industrial Servo Motion

The 10.2 N·m continuous torque rating provides the motor with a useful continuous load capability for medium-sized industrial servo axes.

The approximately 27.1 N·m peak torque rating provides additional short-duration torque capacity during acceleration, deceleration, indexing, and other dynamic operating conditions.

The motor’s approximately 2.6 kW rated power class makes it suitable for applications where a compact servo motor is required but a small motor does not provide sufficient torque.

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4. Mechanical Dimensions and Weight

Mechanical dimensions are particularly important when selecting a replacement servo motor.

The MPL-B4540F-RK74AA uses the 130 mm frame / 101.6 mm stack configuration.

Mechanical Parameter	Specification
Model	MPL-B4540F-RK74AA
Frame Size	130 mm
Frame Size	Approx. 5.12 in.
Magnet Stack	101.6 mm
Stack Length	Approx. 4.00 in.
Overall Motor Length	Approx. 330 mm class
Mounting Standard	IEC Metric
Mounting Flange	Metric
Mounting Holes	Free Mounting Holes, Type FF
Shaft Type	Keyless
Shaft Key	None
Connector	SpeedTEC DIN
Connector Style	Right Angle
Connector Rotation	180°
Brake	24 V DC
Approximate Weight	9.1 kg

The approximately 9.1 kg motor weight is a useful reference for machine design, although the actual mass can vary slightly by production revision, motor configuration, and documentation version.

The 130 mm frame and 101.6 mm stack are the key mechanical dimensions that should be checked when replacing an existing motor.

The keyless shaft also requires special attention during mechanical integration. The coupling, gearbox, pulley, or other transmission component should be designed for a compatible keyless shaft arrangement.

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5. Model Number Breakdown

The model designation provides useful information about the motor configuration.

Model Code	Description
MPL	MPL Low-Inertia Servo Motor Series
B	460 V class configuration
45	130 mm frame size
40	101.6 mm magnet stack
F	3000 rpm speed class
R	Resolver feedback
K	Keyless shaft extension
7	Right-angle, rotatable SpeedTEC DIN connector
4	24 V DC brake
AA	Configuration / revision designation

The RK74AA configuration can therefore be understood as a 3000 rpm B4540F motor using resolver feedback, a keyless shaft, a right-angle rotatable connector, and a 24 V DC holding brake.

This makes the model easy to distinguish from other B4540F configurations.

For example, an RJ72AA configuration uses a keyed shaft and no brake, while an RK74AA uses a keyless shaft and includes the brake.

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6. Product Introduction

The MPL-B4540F-RK74AA is designed for closed-loop industrial motion control.

In a typical servo system, the motor is connected to a servo drive and motion controller. The drive supplies controlled electrical power to the motor, while the resolver provides motor position information.

The controller can therefore command precise speed, position, acceleration, and deceleration profiles.

This type of control is especially important in automated machinery where a motor cannot simply run at a fixed speed.

For example, a packaging machine may need to accelerate a mechanism, move it to a specific position, stop precisely, wait for another machine operation, and then immediately start the next cycle.

A low-inertia servo motor is well suited to this type of repetitive operation.

The motor’s approximately 10.2 N·m continuous torque provides the capacity required for sustained operation, while the approximately 27.1 N·m peak torque gives additional dynamic capability during acceleration and short-duration load changes.

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

This is particularly useful when the motor is installed on a vertical axis or on a mechanism where the shaft should remain stationary after the servo drive stops actively controlling the motor.

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7. Low-Inertia Motor Design

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

Low rotor inertia allows the motor to respond quickly to changes in the commanded speed.

This can be particularly important in applications with:

• Frequent acceleration and deceleration
• Short machine cycles
• Rapid indexing
• Repeated forward and reverse movement
• High positioning frequency
• Synchronized multi-axis motion
• Fast pick-and-place operations

A low-inertia motor can help reduce the time required to change speed, although actual machine performance depends on the complete servo system, including load inertia, drive tuning, mechanical transmission, controller settings, and machine structure.

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8. Continuous and Peak Torque

The MPL-B4540F-RK74AA provides approximately 10.2 N·m continuous torque.

This represents the motor’s useful continuous torque capability under the applicable operating conditions.

For short-duration dynamic events, the motor can provide approximately 27.1 N·m peak torque.

The difference between continuous and peak torque is important when selecting a servo motor.

A machine may require only 8–10 N·m during steady operation but temporarily require much higher torque while accelerating a heavy load.

The peak torque capability gives the servo system additional dynamic capacity for these short periods.

When selecting the motor, both continuous and peak torque requirements should therefore be calculated.

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9. 3000 rpm Speed Class

The motor is designed for the 3000 rpm speed class.

This speed is suitable for a broad range of industrial automation applications.

It provides a useful balance between rotational speed and torque.

Typical mechanical systems that can use this speed class include:

• Ball-screw drives
• Belt-driven positioning systems
• Gear-reduced mechanisms
• Rotary indexing systems
• Feed mechanisms
• Conveyor systems
• Packaging mechanisms
• Automated assembly systems

The final operating speed should be selected according to the machine’s actual load and motion profile.

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10. Resolver Feedback

The MPL-B4540F-RK74AA uses a 2-pole resolver as its feedback device.

The resolver provides information about the motor’s rotational position to the servo control system.

This feedback enables closed-loop regulation of the motor.

Resolver feedback is particularly attractive in industrial applications where rugged feedback performance and reliable operation are important.

Compared with different encoder architectures, resolver-based systems are often selected for their industrial durability and compatibility with established servo-control systems.

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11. Keyless Shaft Advantages

One of the most important characteristics of the RK74AA configuration is its keyless shaft.

The absence of a traditional shaft key allows the motor to be integrated with mechanical transmission systems designed around clamping connections.

Typical mechanical interfaces can include:

• Clamping couplings
• Friction-lock hubs
• Shrink-fit components
• Keyless gearbox inputs
• Precision couplings
• Clamp-type pulley connections

The keyless configuration can provide a clean mechanical interface and can be particularly useful in precision motion systems.

The coupling method must be properly selected for the transmitted torque, acceleration, stopping loads, and shaft dimensions.

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12. Integrated 24 V DC Brake

The 24 V DC holding brake is one of the most important features of the MPL-B4540F-RK74AA.

The brake allows the motor shaft to be mechanically held when the servo system is not actively driving the motor.

This is particularly useful for:

• Vertical positioning axes
• Z-axis mechanisms
• Lifting equipment
• Vertical ball-screw systems
• Material-handling lifts
• Automated machine slides
• Robotic vertical axes
• Positioning systems requiring shaft holding

The brake should normally be considered a holding device rather than the primary means of dynamic stopping.

For normal machine motion, the servo drive should control acceleration and deceleration. The brake is used when the machine requires mechanical holding after the axis has stopped or when the servo drive is disabled.

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13. Connector Design

The motor uses a SpeedTEC DIN connector in a right-angle configuration.

The connector can be rotated through approximately 180°.

This feature is useful for machine builders because cable routing can become difficult in compact equipment.

The connector orientation can be adjusted to better suit:

• Motor mounting position
• Cable tracks
• Machine guards
• Adjacent motors
• Mechanical frames
• Control cabinet routing
• Limited installation space

The right-angle connector can also help reduce the amount of clearance required around the motor connection.

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14. Main Product Advantages

14.1 Low-Inertia Performance

The low-inertia design supports fast acceleration and deceleration.

This is especially useful for high-cycle industrial machinery where every reduction in positioning time can contribute to machine productivity.

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14.2 10.2 N·m Continuous Torque

The approximately 10.2 N·m continuous torque rating provides a useful performance level for medium-duty servo axes.

It can support sustained mechanical loads while maintaining the compact 130 mm frame format.

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14.3 27.1 N·m Peak Torque

The approximately 27.1 N·m peak torque capability provides additional dynamic torque for acceleration and short-duration load changes.

This gives the motor useful performance margin in applications with demanding motion profiles.

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14.4 Integrated Holding Brake

The 24 V DC brake makes the RK74AA configuration particularly useful for vertical axes and applications where the motor shaft must remain stationary after power is removed.

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14.5 Keyless Shaft

The keyless shaft is suitable for clamp-type and friction-lock mechanical transmission systems.

It can simplify integration when the machine has already been designed around a keyless coupling architecture.

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14.6 Resolver Feedback

The resolver provides closed-loop position feedback for servo control.

This allows the motor to operate as part of a controlled position, velocity, and torque system.

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14.7 Compact Frame

The 130 mm frame provides a useful balance between physical size and torque capability.

This can help reduce the required machine footprint.

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14.8 Flexible Cable Routing

The right-angle connector with approximately 180° rotation gives machine designers additional flexibility.

This can be especially useful in machines where motor cables must be routed through narrow spaces.

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14.9 IEC Metric Mounting

The IEC metric mounting arrangement is suitable for machinery designed around metric mechanical dimensions.

The free-mounting-hole arrangement can provide additional flexibility during machine design.

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15. Typical Applications

15.1 Packaging Machinery

Packaging machinery frequently requires rapid, repeatable, and synchronized motion.

The MPL-B4540F-RK74AA can be considered for:

• Indexing mechanisms
• Product feeders
• Film-feed systems
• Labeling equipment
• Cutting mechanisms
• Carton handling
• Product positioning
• Rotary indexing systems

The low-inertia construction is useful for rapid repetitive motion.

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15.2 Material Handling

The motor can be used in automated material-handling equipment requiring controlled movement.

Possible applications include:

• Conveyor positioning
• Transfer mechanisms
• Lift mechanisms
• Automated sorting
• Feed systems
• Indexing conveyors

For vertical material-handling applications, the integrated brake is particularly useful.

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15.3 CNC and Machine Tools

The motor can be used on selected CNC and machine-tool axes.

Potential applications include:

• Feed axes
• Positioning axes
• Rotary auxiliary axes
• Automated tool-handling systems
• Workpiece positioning
• Machine slides

The brake configuration can be useful for vertical machine axes.

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15.4 Automated Assembly

Automated assembly equipment requires repeatable positioning and fast cycle times.

The motor can be used for:

• Rotary indexing
• Pick-and-place mechanisms
• Component positioning
• Assembly fixtures
• Linear positioning systems
• Automated workstations

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15.5 Printing and Converting

Printing and converting machines often require coordinated speed and position control.

Potential applications include:

• Web handling
• Roller control
• Feed mechanisms
• Cutting
• Indexing
• Registration systems

The low-inertia construction is useful when the machine repeatedly changes speed.

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15.6 Robotics

The motor can be used for selected industrial automation and robotic mechanisms.

Applications can include:

• Rotary positioning
• Automated fixtures
• Machine-tending mechanisms
• Auxiliary positioning axes
• Material transfer

For a robotic axis, motor selection should be based on the complete load inertia, duty cycle, acceleration profile, gearbox ratio, and mechanical structure.

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16. Application Suitability

Application	Suitability	Main Advantage
Packaging Machinery	High	Fast indexing and positioning
Automated Assembly	High	Repeatable servo motion
Horizontal Conveyor	High	Low-inertia positioning
Rotary Indexing	High	Controlled speed and position
CNC Feed Axis	High	Closed-loop servo control
Vertical Axis	High with proper brake design	Integrated 24 V brake
Material Handling	High	Torque and dynamic response
Printing Equipment	High	Coordinated motion
Pick-and-Place	High	Rapid acceleration/deceleration
High-Speed Spindle	Limited	3000 rpm class is not primarily a spindle configuration

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17. Five Recommended Related Models

The following models are closely related to the MPL-B4540F-RK74AA and can be considered when the mechanical or electrical requirements change.

Model	Speed	Continuous Torque	Peak Torque	Power	Feedback	Shaft	Brake	Dimensions	Weight
MPL-B4540F-RK72AA	3000 rpm	10.2 N·m	27.1 N·m	Approx. 2.6 kW	Resolver	Keyless	No	130 × 101.6 mm	Approx. 9 kg class
MPL-B4540F-RJ74AA	3000 rpm	10.2 N·m	27.1 N·m	Approx. 2.6 kW	Resolver	Keyed	24 V DC	130 × 101.6 mm	Approx. 13 kg
MPL-B4540F-RJ72AA	3000 rpm	10.2 N·m	27.1 N·m	Approx. 2.6 kW	Resolver	Keyed	No	130 × 101.6 mm	Approx. 11 kg
MPL-B4530F-RK74AA	3000 rpm	Approx. 8.25 N·m	Approx. 20.3 N·m	Approx. 2.1 kW	Resolver	Keyless	24 V DC	130 × 76.2 mm	Approx. 10.9 kg
MPL-B4560F-RK74AA	3000 rpm	Approx. 14.1 N·m	Approx. 34.4 N·m	Approx. 3.2 kW	Resolver	Keyless	24 V DC	130 × 152.4 mm	Approx. 12–13 kg class

MPL-B4540F-RK72AA

The RK72AA is the closest no-brake alternative to the target motor.

It retains the same basic B4540F frame, stack length, resolver feedback, keyless shaft, connector arrangement, and 3000 rpm operating class.

The major difference is that the RK72AA does not include the integrated 24 V DC brake.

It is therefore particularly suitable for horizontal axes where mechanical shaft holding is not required.

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MPL-B4540F-RJ74AA

The RJ74AA provides approximately the same torque and speed performance but changes the shaft from keyless to keyed.

It retains the 24 V DC brake.

This model is suitable when the machine requires both a holding brake and a conventional keyed shaft connection.

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MPL-B4540F-RJ72AA

The RJ72AA is the keyed, no-brake version.

It is particularly useful for horizontal applications where a conventional keyed mechanical connection is preferred.

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MPL-B4530F-RK74AA

The B4530F has a shorter 76.2 mm magnet stack and lower torque capability.

It can be considered where the machine has lower torque requirements and where a shorter motor configuration is desirable.

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MPL-B4560F-RK74AA

The B4560F has a longer 152.4 mm magnet stack and provides a higher torque level.

It is a logical choice when the B4540F’s approximately 10.2 N·m continuous torque is not sufficient.

The larger stack increases the motor’s physical length and mass, so the machine structure and available installation space should be evaluated accordingly.

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18. Five Popular Models from the Same Brand

Model	Feedback	Speed	Continuous Torque	Peak Torque	Power Class	Shaft	Brake	Dimensions	Weight
MPL-B4540F-MJ74AA	Multi-turn absolute	3000 rpm	10.2 N·m	27.1 N·m	Approx. 2.6 kW	Keyed	24 V DC	130 × 101.6 mm	Approx. 10–11 kg
MPL-B4540F-MK74AA	Multi-turn absolute	3000 rpm	10.2 N·m	27.1 N·m	Approx. 2.6 kW	Keyless	24 V DC	130 × 101.6 mm	Approx. 10–12 kg
MPL-B4540F-HJ74AA	High-resolution incremental	3000 rpm	10.2 N·m	27.1 N·m	Approx. 2.6 kW	Keyed	24 V DC	130 × 101.6 mm	Approx. 11 kg class
MPL-B4560F-MJ74AA	Multi-turn absolute	3000 rpm	Approx. 14.1 N·m	Approx. 34.4 N·m	Approx. 3.2 kW	Keyed	24 V DC	130 × 152.4 mm	Approx. 12 kg class
MPL-B540K-MJ74AA	Multi-turn absolute	4000 rpm	Approx. 19.4 N·m	Approx. 48.6 N·m	Approx. 5.4 kW	Keyed	24 V DC	Approx. 165 × 101.6 mm	Approx. 15 kg

These models cover several common servo selection requirements.

The MPL-B4540F-MJ74AA is close to the target motor in physical size and torque but uses multi-turn absolute feedback.

The MPL-B4540F-MK74AA is especially interesting when the application requires a keyless shaft and holding brake while using a different feedback architecture.

The MPL-B4540F-HJ74AA uses high-resolution incremental feedback and is appropriate for control systems designed around that feedback technology.

The MPL-B4560F-MJ74AA provides higher torque while remaining within the same general 130 mm frame family.

The MPL-B540K-MJ74AA represents a larger motor class, providing substantially greater torque and a higher 4000 rpm speed class.

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19. Direct Comparison of the Four Closest B4540F Resolver Models

Parameter	MPL-B4540F-RK72AA	MPL-B4540F-RK74AA	MPL-B4540F-RJ72AA	MPL-B4540F-RJ74AA
Frame	130 mm	130 mm	130 mm	130 mm
Stack	101.6 mm	101.6 mm	101.6 mm	101.6 mm
Speed	3000 rpm	3000 rpm	3000 rpm	3000 rpm
Continuous Torque	10.2 N·m	10.2 N·m	10.2 N·m	10.2 N·m
Peak Torque	27.1 N·m	27.1 N·m	27.1 N·m	27.1 N·m
Feedback	Resolver	Resolver	Resolver	Resolver
Shaft	Keyless	Keyless	Keyed	Keyed
Brake	No	24 V DC	No	24 V DC
Connector	Right-angle DIN	Right-angle DIN	Right-angle DIN	Right-angle DIN
Connector Rotation	180°	180°	180°	180°
Mounting	IEC Metric	IEC Metric	IEC Metric	IEC Metric
Approx. Weight	9 kg class	9.1 kg	11 kg class	13 kg class

This comparison shows the main reason to select the RK74AA configuration.

It combines the keyless shaft of the RK family with the 24 V DC brake of the 74 configuration.

This makes it particularly attractive for machinery where the mechanical transmission is designed around a keyless shaft but the axis still requires a holding brake.

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20. RK74AA vs. RK72AA

The difference between these two models is primarily the brake configuration.

Feature	MPL-B4540F-RK74AA	MPL-B4540F-RK72AA
Frame	130 mm	130 mm
Stack	101.6 mm	101.6 mm
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
Feedback	Resolver	Resolver
Shaft	Keyless	Keyless
Brake	24 V DC	None
Connector	Right-angle DIN	Right-angle DIN
Application	Axes requiring shaft holding	Axes without brake requirement

For a horizontal positioning axis, the RK72AA may be sufficient.

For a vertical positioning axis, lifting mechanism, or other load where the shaft must be held mechanically, the RK74AA provides an important additional feature.

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21. RK74AA vs. RJ74AA

The difference between these two brake-equipped models is primarily the shaft configuration.

Feature	MPL-B4540F-RK74AA	MPL-B4540F-RJ74AA
Frame	130 mm	130 mm
Stack	101.6 mm	101.6 mm
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
Feedback	Resolver	Resolver
Shaft	Keyless	Keyed
Brake	24 V DC	24 V DC
Connector	Right-angle DIN	Right-angle DIN
Best Mechanical Match	Clamp-type coupling	Keyed coupling

If the machine already uses a keyed coupling or gearbox input, the RJ74AA may be the more natural selection.

If the machine uses a keyless coupling system, the RK74AA is the better mechanical match.

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22. Application Selection by Machine Type

Machine Type	Recommended Configuration	Reason
Horizontal Conveyor	RK72AA	Brake often unnecessary
Vertical Conveyor	RK74AA	Holding brake required
Vertical Ball Screw	RK74AA	Shaft holding capability
Packaging Indexer	RK72AA / RK74AA	Depends on holding requirement
Rotary Table	RK72AA	Often no brake required
Vertical Rotary Axis	RK74AA	Brake provides holding
CNC Horizontal Axis	RK72AA	Keyless + no brake can be suitable
CNC Vertical Axis	RK74AA	Brake can help hold axis
Keyless Gearbox	RK74AA	Keyless shaft compatibility
Keyed Gearbox	RJ74AA	Keyed shaft compatibility

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23. Important Engineering Considerations

Servo motor selection should not be based only on the motor’s rated torque.

The complete machine load should be evaluated.

Important parameters include:

• Continuous load torque
• Peak acceleration torque
• Load inertia
• Reflected inertia
• Maximum operating speed
• Acceleration time
• Deceleration time
• Duty cycle
• Gear ratio
• Screw pitch
• Belt ratio
• Mechanical efficiency
• Vertical load requirements
• Holding-brake requirements
• Ambient temperature
• Installation environment
• Cable routing
• Servo-drive compatibility

The motor’s 10.2 N·m continuous torque should therefore be compared with the actual machine load rather than treated as a universal application limit.

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24. Brake Selection Considerations

The integrated 24 V DC brake is a major advantage of the RK74AA, but the brake should be correctly integrated into the machine’s control system.

The brake is intended primarily for holding.

For a vertical load, the servo drive should normally decelerate the axis in a controlled manner before the brake is engaged.

The brake should not automatically be treated as the emergency stopping mechanism for every machine.

The machine safety design should determine how the brake is controlled, when it is released, when it is engaged, and what happens during power loss.

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25. Mechanical Integration

The keyless shaft requires careful coupling selection.

A suitable coupling should be capable of transmitting the required continuous and peak torque while accommodating the actual shaft dimensions and machine alignment.

Proper alignment is particularly important in servo systems because excessive radial or axial loading can reduce bearing life and affect machine performance.

The motor should be mounted on a sufficiently rigid structure.

Machine vibration, coupling misalignment, excessive radial load, and excessive axial load should be avoided.

The 130 mm frame provides a compact mounting package, but the actual machine mounting structure should be designed to withstand the motor torque and the forces generated by the driven mechanism.

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26. Why Choose MPL-B4540F-RK74AA?

The MPL-B4540F-RK74AA is a strong choice when the application requires the following combination:

• 130 mm frame
• 101.6 mm magnet stack
• 3000 rpm operation
• Approximately 10.2 N·m continuous torque
• Approximately 27.1 N·m peak torque
• Approximately 2.6 kW power class
• Low-inertia construction
• Resolver feedback
• Keyless shaft
• 24 V DC holding brake
• Right-angle SpeedTEC DIN connector
• 180° connector rotation
• IEC metric mounting

This combination makes the model particularly useful for machines where both mechanical flexibility and shaft holding are required.

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27. Overall Product Evaluation

The Allen-Bradley MPL-B4540F-RK74AA is a compact, industrial-grade low-inertia servo motor designed for controlled motion applications.

Its approximately 10.2 N·m continuous torque and 27.1 N·m peak torque provide a useful performance range for medium-duty servo axes.

The 3000 rpm speed class makes it suitable for general-purpose industrial motion systems.

The resolver feedback provides closed-loop motor position information, while the low-inertia design supports fast dynamic response.

The keyless shaft is particularly useful for clamp-type mechanical transmission systems.

The integrated 24 V DC holding brake makes this configuration more suitable for vertical axes and other applications where the motor shaft must remain mechanically held after the servo system stops.

The right-angle SpeedTEC DIN connector with 180° rotation provides additional installation flexibility and can simplify cable routing in compact machinery.

From a selection standpoint, the most important characteristic of the RK74AA is the combination of keyless shaft + resolver feedback + 24 V DC brake.

For applications requiring a keyed shaft, the RJ74AA is a closer mechanical alternative.

For applications that do not require a holding brake, the RK72AA provides a similar motor configuration without the brake.

For applications requiring more torque, the B4560F configuration is a logical step upward within the same general motor family.

Overall, the MPL-B4540F-RK74AA is well suited to industrial automation, packaging, material handling, machine tools, automated assembly, indexing systems, positioning equipment, and selected vertical-axis applications where accurate servo control and mechanical shaft holding are required.

For replacement applications, the final selection should always be checked against the actual motor nameplate, mechanical drawing, coupling dimensions, brake requirements, resolver interface, servo-drive compatibility, load inertia, duty cycle, and machine safety requirements.