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MPL-B520K-MK74AA Servo Motor

1. Product Overview

The MPL-B520K-MK74AA is a high-performance low-inertia rotary servo motor from the MP-Series MPL low-inertia servo motor family. It is designed for industrial motion-control applications that require accurate positioning, rapid acceleration and deceleration, stable speed control, and reliable repetitive operation.

This model belongs to the 460 V AC class, uses a 165 mm frame size, has a 50.8 mm magnetic stack length, and operates in the 4000 rpm maximum-speed class. It is equipped with a multi-turn high-resolution absolute encoder, a keyless shaft extension, a right-angle SpeedTEC DIN connector, and an integrated 24 V DC holding brake.

The combination of low rotor inertia, high-speed operation, absolute feedback, and a built-in brake makes this motor particularly suitable for automated machinery in which both dynamic motion and load-holding capability are important.

The brake is one of the most important differences between the MPL-B520K-MK74AA and the closely related MPL-B520K-MK72AA. The MK74AA includes a 24 V DC brake, while the MK72AA is the non-brake version.

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2. Brand and Product Series

Item	Information
Model	MPL-B520K-MK74AA
Brand	Allen-Bradley
Product Family	MP-Series
Product Series	MPL Low-Inertia Servo Motors
Product Type	Rotary AC servo motor
Motor Technology	Low-inertia brushless servo
Voltage Class	460 V AC
Speed Class	4000 rpm
Frame Size	165 mm / 6.50 in
Magnetic Stack Length	50.8 mm / 2.00 in
Feedback	Multi-turn high-resolution absolute encoder
Shaft	Keyless shaft extension
Brake	24 V DC integral brake
Connector	SpeedTEC DIN connector
Connector Style	Right-angle
Connector Adjustment	Approximately 180° rotatable
Mounting	IEC metric
Mounting Hole Configuration	Free mounting holes, Type FF
Typical Application	Industrial motion control

The MPL designation identifies the low-inertia servo motor family. The product family is intended for applications in which the motor must respond quickly to position, speed, and torque commands.

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3. Model Number Explanation

The model number contains information about the motor’s principal configuration.

Model Section	Configuration
MPL	MPL low-inertia brushless servo motor family
B	460 V AC class
5	Frame size 5, approximately 165 mm
20	50.8 mm magnetic stack
K	4000 rpm speed class
M	Multi-turn high-resolution absolute feedback
K	Keyless shaft extension
7	SpeedTEC DIN right-angle connector
4	24 V DC brake
AA	Standard model configuration

The model code is especially useful when comparing closely related motors. A change in the shaft, brake, feedback, connector, or speed configuration can produce a different motor model even when the basic frame and torque class remain similar.

For this particular motor, the K shaft designation indicates the keyless shaft configuration, while the 4 brake designation indicates the integral 24 V DC brake.

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4. Detailed Technical Parameters

Parameter	MPL-B520K-MK74AA
Model	MPL-B520K-MK74AA
Motor Type	Low-inertia brushless AC rotary servo motor
Product Series	MPL Low-Inertia Servo Motors
Voltage Class	460 V AC
Maximum Speed	4000 rpm
Typical Rated Output Speed	Approximately 3500 rpm
Continuous Stall Torque	10.7 N·m
Peak Stall Torque	23.2 N·m
Rated Continuous Power	Approximately 3.5 kW
Rotor Inertia	Approximately 0.000897 kg·m²
Feedback	Absolute multi-turn
Feedback Resolution	Sin/Cos, 1024 cycles/revolution
Feedback Protocol	Hiperface
Shaft Type	Keyless
Shaft Key	No
Shaft Seal	No standard shaft seal
Brake	24 V DC integral brake
Connector	SpeedTEC DIN
Connector Orientation	Right-angle
Connector Rotation	Approximately 180°
Frame Size	165 mm
Frame Size in Inches	6.50 in
Magnetic Stack Length	50.8 mm
Magnetic Stack in Inches	2.00 in
Mounting	IEC metric flange mounting
Mounting Holes	Free mounting holes / Type FF
Motor Weight	Approximately 13.9 kg
Motor Weight in Pounds	Approximately 30.6 lb
Motor Construction	Low-inertia permanent-magnet servo motor
Environmental Temperature Class	Up to approximately 40 °C operating condition
Typical Use	Positioning, indexing, feeding, packaging, assembly and automated machinery

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5. Dimensions and Mechanical Parameters

The 165 mm frame size is one of the key mechanical specifications of the MPL-B520K-MK74AA. The motor also has a 50.8 mm magnetic stack length.

Mechanical Parameter	Specification
Model	MPL-B520K-MK74AA
Frame Size	165 mm
Frame Size	6.50 in
Magnetic Stack Length	50.8 mm
Magnetic Stack Length	2.00 in
Mounting Standard	IEC metric
Flange Mounting	Metric flange
Mounting Hole Type	Free mounting holes / Type FF
Shaft Design	Keyless
Shaft Key	None
Shaft Seal	None in standard configuration
Brake	Integral 24 V DC brake
Connector	SpeedTEC DIN
Connector Style	Right-angle
Connector Rotation	Approximately 180°
Approximate Weight	13.9 kg
Approximate Weight	30.6 lb
Overall Motor Envelope	Must be confirmed from the applicable mechanical drawing
Exact Flange Dimensions	Must be confirmed from the applicable mechanical drawing
Exact Shaft Projection	Must be confirmed from the applicable mechanical drawing
Exact Overall Length	Must be confirmed from the applicable mechanical drawing

The 165 mm figure refers to the motor frame size and should not be interpreted as the complete external motor length or height.

For an actual machine installation, replacement, or mounting-plate design, the exact mechanical drawing should be used to verify the flange dimensions, mounting-hole spacing, shaft projection, overall motor length, connector clearance, and brake-end dimensions.

The approximate 13.9 kg weight is particularly important for moving axes, vertical axes, robot mechanisms, and equipment where motor mass affects the total load inertia.

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6. Electrical and Performance Characteristics

The MPL-B520K-MK74AA is designed around a relatively high-speed servo operating range.

Its maximum speed is approximately 4000 rpm, while its continuous stall torque is approximately 10.7 N·m and its peak stall torque is approximately 23.2 N·m.

The approximately 3.5 kW continuous output rating places the motor in a useful medium-power industrial servo class.

Performance Item	Value
Model	MPL-B520K-MK74AA
Maximum Speed	4000 rpm
Rated Output Speed	Approx. 3500 rpm
Continuous Stall Torque	10.7 N·m
Peak Stall Torque	23.2 N·m
Continuous Rated Power	3.5 kW
Rotor Inertia	0.000897 kg·m²
Feedback	Multi-turn absolute
Brake Voltage	24 V DC
Voltage Class	460 V AC

The difference between continuous torque and peak torque is important.

The 10.7 N·m continuous torque represents the motor’s continuous torque capability under the specified operating conditions, while the 23.2 N·m peak torque is intended for short-duration dynamic requirements such as acceleration, deceleration, or transient load conditions.

The actual application should always be checked against the complete motor torque-speed curve and the drive configuration rather than using peak torque as a continuous operating value.

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7. Multi-Turn Absolute Feedback

The motor uses a multi-turn high-resolution absolute encoder.

This is one of the major features of the MPL-B520K-MK74AA because the servo drive can use feedback information to determine the motor’s position, speed, and movement direction.

The multi-turn configuration is particularly useful when the motor makes multiple revolutions during normal operation.

Typical applications include:

• Screw-driven positioning axes
• Rotary indexing
• Conveyor synchronization
• Packaging mechanisms
• Automated assembly
• Material positioning
• Winding mechanisms
• Rotary tables
• Feeding mechanisms
• High-speed indexing systems

The feedback system helps the motion controller maintain a closed-loop relationship between the commanded movement and the actual motor position.

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8. Keyless Shaft Design

The MPL-B520K-MK74AA uses a keyless shaft extension.

This is important when selecting a coupling, pulley, gearbox, timing-belt mechanism, or other transmission component.

A keyless shaft is normally paired with a compatible clamping hub or other suitable mechanical connection.

The keyless configuration can be advantageous where the mechanical system is designed around a friction-clamping connection rather than a conventional shaft key.

The main benefits can include:

• Clean mechanical shaft interface
• Suitable for compatible clamping couplings
• Convenient coupling installation
• Reduced dependence on a traditional keyway
• Good suitability for precision motion systems
• Flexible mechanical transmission design

However, the shaft interface must always be matched to the actual coupling or transmission component.

A keyed coupling should not simply be installed on the motor without confirming mechanical compatibility.

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9. Integrated 24 V DC Brake

The 24 V DC brake is one of the most important features of the MK74AA configuration.

The brake is particularly useful when the motor is used in applications where the load needs to remain mechanically held while the motor is stopped or when servo power is removed.

Typical applications include:

• Vertical lifting axes
• Vertical positioning systems
• Hoists
• Z-axis mechanisms
• Elevating equipment
• Vertical ball-screw axes
• Load-holding mechanisms
• Machines where uncontrolled movement after power loss must be minimized

The brake should not be treated as a substitute for a complete safety system. Its suitability depends on the machine’s load, inertia, stopping requirements, safety architecture, and mechanical design.

The brake is one of the major reasons to select MPL-B520K-MK74AA instead of the otherwise closely related MPL-B520K-MK72AA.

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10. Connector Design

The motor uses a SpeedTEC DIN right-angle connector.

The right-angle connector configuration is useful in industrial machines where available installation space is limited.

The connector can be rotated through approximately 180 degrees, allowing the cable exit direction to be adjusted to the machine layout.

This can be helpful when:

• The motor is installed close to a machine frame.
• Cable routing space is restricted.
• The machine has a compact enclosure.
• Multiple motors are installed close together.
• The cable must be routed around guarding or structural components.

Good cable routing can reduce unnecessary cable bending and make installation and maintenance easier.

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11. Product Introduction

The MPL-B520K-MK74AA is designed for applications where a conventional induction motor is not sufficient and accurate servo control is required.

Unlike a standard motor that primarily provides continuous rotation, a servo motor operates as part of a closed-loop motion system.

The controller sends a command to the servo drive, the drive supplies the appropriate electrical power to the motor, and the encoder provides feedback about the motor’s actual movement.

This closed-loop operation allows the system to control:

• Position
• Speed
• Direction
• Acceleration
• Deceleration
• Torque response
• Repetitive motion

The low-inertia design makes the motor particularly suitable for applications with frequent speed changes.

Instead of spending a large amount of energy accelerating a heavy rotor, a low-inertia motor can respond relatively quickly to changes in the commanded motion.

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12. Main Product Advantages

12.1 Low-Inertia Design

The low-inertia rotor is one of the main advantages of the MPL series.

Low inertia is valuable for machines that repeatedly accelerate and decelerate.

Examples include indexing machines, packaging equipment, pick-and-place systems, feeding mechanisms, and automated assembly equipment.

A lower rotor inertia can help the servo system achieve quicker dynamic response when properly matched to the machine load.

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12.2 High-Speed Operation

The motor has a 4000 rpm maximum-speed class.

This makes it appropriate for high-cycle industrial machinery where the motor must complete many movements in a short period.

High-speed operation can help reduce machine cycle time when the mechanical transmission, load, and servo drive are all correctly matched to the required operating point.

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12.3 Strong Torque Capability

The approximately 10.7 N·m continuous torque and 23.2 N·m peak torque provide a useful combination for medium-power motion systems.

The motor can therefore support both normal continuous load requirements and short-duration acceleration or transient torque requirements.

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12.4 Multi-Turn Absolute Feedback

The multi-turn absolute feedback system provides accurate position information for closed-loop control.

This is especially valuable for applications where position accuracy and repeatability are important.

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12.5 Integrated Brake

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

This makes the MK74AA version particularly attractive for vertical or load-holding applications.

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12.6 Keyless Shaft

The keyless shaft provides compatibility with suitable clamping-style mechanical transmission components.

It is a useful configuration for precision mechanical systems where a conventional keyed shaft is not required.

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12.7 Flexible Connector Orientation

The right-angle connector with approximately 180° rotation provides additional installation flexibility.

This can be especially useful in compact machine designs.

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12.8 Medium-Power Industrial Servo Class

With approximately 3.5 kW continuous output, the motor is positioned between smaller compact servo motors and larger high-torque industrial servo motors.

This makes it useful for applications that need more capability than a small servo but do not require a very large motor.

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13. Typical Applications

Packaging Machinery

Packaging machines frequently require rapid positioning, synchronized movement, and repeated acceleration and deceleration.

The MPL-B520K-MK74AA can be considered for:

• Film feeding
• Product feeding
• Cutting
• Sealing
• Label positioning
• Rotary indexing
• Conveyor synchronization
• Product transfer
• Packaging indexing mechanisms

The low-inertia design can be useful when the machine repeatedly changes speed.

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Automated Assembly Equipment

Automated assembly equipment often requires precise and repeatable movement.

Possible applications include:

• Component positioning
• Rotary indexing tables
• Automated insertion
• Screw mechanisms
• Pick-and-place systems
• Component feeding
• Fixture positioning
• Assembly transfer mechanisms

The absolute multi-turn feedback is useful for systems that need reliable position information.

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Vertical Positioning Equipment

The integrated 24 V DC brake makes the motor particularly suitable for applications in which the load must remain held when the servo is stopped.

Potential applications include:

• Z-axis positioning
• Vertical ball-screw mechanisms
• Lifting equipment
• Elevating platforms
• Vertical transfer systems
• Automated storage mechanisms
• Vertical material-handling axes

The mechanical brake should be selected and evaluated according to the actual load and safety requirements.

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Material Handling

The motor can be used in motion-controlled material-handling systems.

Typical examples include:

• Servo conveyors
• Indexing conveyors
• Transfer systems
• Sorting mechanisms
• Position-controlled feeding
• Automated handling axes

The motor’s speed and torque capabilities can be useful when the machine needs controlled acceleration and deceleration.

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Printing and Converting Equipment

Servo motors are widely used in machinery that needs coordinated movement between rollers, feeders, cutters, and other mechanical elements.

Potential applications include:

• Web feeding
• Roller control
• Material positioning
• Cutting
• Registration control
• Tension-related motion
• Indexing mechanisms

The exact motor size should be selected according to the material load and required acceleration profile.

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Textile Machinery

The motor can also be considered for textile machinery where accurate rotary motion is required.

Potential applications include:

• Feeding
• Winding
• Roller control
• Positioning
• Indexing
• Synchronized material movement

The motor’s brake configuration may also be useful in certain vertical or load-holding mechanisms.

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14. Five Same-Series or Closely Related Models

The following models are closely related to the MPL-B520K-MK74AA and are useful when comparing shaft, brake, feedback, or configuration requirements.

Model	Voltage Class	Frame	Stack	Max Speed	Continuous Torque	Peak Torque	Power	Feedback	Shaft	Brake	Approx. Weight
MPL-B520K-MJ72AA	460 V AC	165 mm	50.8 mm	4000 rpm	10.7 N·m	23.2 N·m	3.5 kW	Multi-turn absolute	Keyed	No	Approx. 9.8 kg
MPL-B520K-MJ74AA	460 V AC	165 mm	50.8 mm	4000 rpm	10.7 N·m	23.2 N·m	3.5 kW	Multi-turn absolute	Keyed	24 V DC	Approx. 13.9 kg
MPL-B520K-MK72AA	460 V AC	165 mm	50.8 mm	4000 rpm	10.7 N·m	23.2 N·m	3.5 kW	Multi-turn absolute	Keyless	No	Approx. 11.3 kg
MPL-B520K-SJ22AA	460 V AC	165 mm	50.8 mm	4000 rpm	Approx. 10.7 N·m	Approx. 23.2 N·m	Approx. 3.5 kW	Alternative feedback configuration	Keyed	No	Approx. 9.8–11 kg
MPL-B540K-MJ74AA	460 V AC	165 mm class	Longer stack	4000 rpm	Approx. 19.4 N·m	Approx. 48.6 N·m	5.4 kW	Multi-turn absolute	Keyed	24 V DC	Approx. 15 kg

The closest alternatives are the other B520K configurations.

The MPL-B520K-MJ72AA is appropriate when the machine needs a keyed shaft without a brake.

The MPL-B520K-MJ74AA provides a keyed shaft and 24 V DC brake.

The MPL-B520K-MK72AA keeps the keyless shaft but removes the integral brake.

The MPL-B520K-SJ22AA represents an alternative feedback/configuration direction within the same general B520K motor class.

The MPL-B540K-MJ74AA is a more powerful option when the 10.7 N·m continuous torque of the B520K is not sufficient.

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15. Five Popular Models for Broader Brand Comparison

The following models provide useful alternatives across different frame sizes, speeds, torque levels, and power classes.

Model	Frame Class	Stack / Size	Max Speed	Continuous Torque	Peak Torque	Power	Approx. Weight	Typical Position
MPL-B430P-MJ74AA	Approx. 115 mm	Compact	5000 rpm	6.55 N·m	19.8 N·m	2.2 kW	Approx. 5.5 kg	Compact high-speed servo
MPL-B4530F-MJ74AA	Approx. 130 mm	76.2 mm class	3000 rpm	8.25 N·m	20.3 N·m	2.1 kW	Approx. 7.3 kg	Compact medium-torque servo
MPL-B4540F-MJ74AA	Approx. 130 mm	101.6 mm class	3000 rpm	10.2 N·m	27.1 N·m	2.6 kW	Approx. 8.6 kg	Medium-duty positioning
MPL-B4560F-MJ74AA	Approx. 130 mm	152.4 mm class	3000 rpm	14.1 N·m	34.4 N·m	3.2 kW	Approx. 11.82 kg	Higher-torque compact frame
MPL-B540K-MJ74AA	Approx. 165 mm	Larger stack	4000 rpm	19.4 N·m	48.6 N·m	5.4 kW	Approx. 15 kg	High-torque, higher-power servo

These models cover several practical selection directions.

The MPL-B430P-MJ74AA is a smaller and lighter option when the machine needs higher speed but does not require the torque level of the B520K.

The MPL-B4530F-MJ74AA is suitable for applications where a smaller frame is preferred and the required torque is below the B520K range.

The MPL-B4540F-MJ74AA offers a torque level close to the B520K while using a smaller frame class and a lower 3000 rpm speed class.

The MPL-B4560F-MJ74AA provides more torque than the B520K in a compact frame class, making it useful when torque is more important than maximum speed.

The MPL-B540K-MJ74AA is the logical direction when considerably more torque and power are required.

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16. B520K Family Comparison

Parameter	MPL-B520K-MJ72AA	MPL-B520K-MJ74AA	MPL-B520K-MK72AA	MPL-B520K-MK74AA
Frame	165 mm	165 mm	165 mm	165 mm
Stack	50.8 mm	50.8 mm	50.8 mm	50.8 mm
Max Speed	4000 rpm	4000 rpm	4000 rpm	4000 rpm
Continuous Torque	10.7 N·m	10.7 N·m	10.7 N·m	10.7 N·m
Peak Torque	23.2 N·m	23.2 N·m	23.2 N·m	23.2 N·m
Power	3.5 kW	3.5 kW	3.5 kW	3.5 kW
Feedback	Multi-turn absolute	Multi-turn absolute	Multi-turn absolute	Multi-turn absolute
Shaft	Keyed	Keyed	Keyless	Keyless
Brake	No	24 V DC	No	24 V DC
Approx. Weight	9.8 kg	13.9 kg	11.3 kg	13.9 kg
Recommended Use	Horizontal axis	Load-holding axis	Horizontal axis	Vertical/load-holding axis

This comparison shows that the main difference between these B520K models is not the basic motor torque or speed. Instead, the most important differences are the shaft type and brake configuration.

For example, if the machine already uses a keyless coupling and requires a brake, the MPL-B520K-MK74AA is the natural configuration.

If the machine uses a keyed coupling and needs a brake, the MPL-B520K-MJ74AA would be the more appropriate direction.

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17. Why Choose the MPL-B520K-MK74AA?

The MPL-B520K-MK74AA is particularly attractive when four characteristics are required at the same time:

1. High-speed servo operation.
2. Low-inertia dynamic response.
3. Keyless shaft connection.
4. Integral 24 V DC brake.

Many industrial machines need the first three characteristics but not necessarily the fourth. The brake makes the MK74AA more suitable for vertical axes and other load-holding applications.

The approximately 3.5 kW continuous power provides a useful amount of output for medium-sized automated equipment, while the 23.2 N·m peak torque provides additional short-term capability for acceleration and transient loads.

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18. Advantages Compared With a Standard Motor

A standard industrial motor is generally selected for continuous rotation and efficiency, while a servo motor is selected when controlled motion is required.

The MPL-B520K-MK74AA provides several capabilities that make it more suitable for motion-control systems:

Requirement	Benefit of the MPL-B520K-MK74AA
Precise positioning	High-resolution absolute feedback
Rapid acceleration	Low rotor inertia
Rapid deceleration	Servo-controlled torque response
Repetitive indexing	Closed-loop positioning
High operating speed	4000 rpm maximum-speed class
Load holding	Integral 24 V DC brake
Keyless transmission	Keyless shaft extension
Restricted installation space	Right-angle rotatable connector
Medium-power machinery	Approximately 3.5 kW continuous power
High dynamic demand	23.2 N·m peak torque

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19. Important Selection Points

When using the MPL-B520K-MK74AA as a replacement motor, several parameters should be checked together.

The first is the shaft configuration. This model uses a keyless shaft, so the existing coupling or transmission must be compatible.

The second is the brake requirement. Because this model includes a 24 V DC brake, the electrical and mechanical system must be designed to accommodate the brake function.

The third is the motor weight. At approximately 13.9 kg, the motor itself contributes a significant amount of mass to a moving axis.

The fourth is the load inertia. The motor’s low rotor inertia does not automatically mean that the complete machine has low inertia. Gearboxes, pulleys, screws, belts, rollers, tooling, and workpieces can all contribute to the reflected load inertia.

The fifth is the torque-speed operating point. The 10.7 N·m continuous torque and 23.2 N·m peak torque should be considered together with the actual operating speed and duty cycle.

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20. Typical Machine Configurations

Horizontal Servo Axis

For a horizontal axis, the motor may drive a ball screw, belt, gearbox, roller, or other transmission.

In this situation, the brake may not be essential, but it can still provide additional holding capability depending on the machine design.

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Vertical Servo Axis

For a vertical axis, the integral brake becomes considerably more important.

A typical system might use the motor to drive:

• Ball screw
• Timing belt
• Gear reducer
• Linear actuator
• Vertical slide

The brake can provide a mechanical holding function when the servo is stopped, subject to the application’s load and safety requirements.

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Rotary Indexing System

The motor can also be used with a rotary table or indexing mechanism.

The low-inertia rotor and high-speed capability can help achieve rapid indexing cycles.

The absolute multi-turn feedback can provide precise motor position information for the motion-control system.

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21. Maintenance and Installation Considerations

The motor should be installed on a sufficiently rigid machine structure.

The mounting surface should be properly aligned, and the coupling should be installed according to the mechanical requirements of the selected transmission component.

Because the motor uses a keyless shaft, excessive clamping force or incorrect coupling installation should be avoided.

Cable routing should also be planned carefully. The right-angle connector allows flexibility, but the cable should still be protected from excessive bending, pulling, abrasion, and mechanical interference.

The brake wiring should be treated separately from the motor power connection and installed according to the control-system design.

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22. Product Selection Summary

Selection Requirement	Recommended Model Direction
Keyless shaft + 24 V brake	MPL-B520K-MK74AA
Keyless shaft + no brake	MPL-B520K-MK72AA
Keyed shaft + 24 V brake	MPL-B520K-MJ74AA
Keyed shaft + no brake	MPL-B520K-MJ72AA
More continuous torque	MPL-B540K family
Smaller and lighter motor	MPL-B430P / MPL-B4530F family
Smaller frame with similar torque	MPL-B4540F family
Higher torque in compact frame	MPL-B4560F family
High-speed compact servo	MPL-B430P family

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23. Overall Product Evaluation

The MPL-B520K-MK74AA is a well-balanced industrial servo motor for applications that require a combination of speed, torque, precise feedback, low dynamic inertia, and mechanical holding capability.

Its 165 mm frame, 50.8 mm magnetic stack, 4000 rpm maximum speed, 10.7 N·m continuous torque, and 23.2 N·m peak torque make it suitable for a broad range of medium-power automated machines.

The multi-turn absolute encoder is valuable for accurate position control, while the keyless shaft provides a specific mechanical interface for compatible couplings and transmission components.

The integrated 24 V DC brake makes this model especially useful for vertical axes and other applications where the load needs to remain mechanically restrained while the motor is stopped.

The approximately 13.9 kg weight should be included when calculating moving-axis mass and overall machine inertia.

From a selection perspective, the most important characteristics of this model are not only its power rating but the combination of:

• 4000 rpm maximum speed
• 10.7 N·m continuous torque
• 23.2 N·m peak torque
• 3.5 kW continuous output
• Low-inertia construction
• Multi-turn absolute feedback
• Keyless shaft
• 24 V DC integral brake
• 165 mm frame
• 50.8 mm magnetic stack
• Right-angle rotatable DIN connector
• Approximately 13.9 kg motor weight

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24. Final Technical Specification Table

Category	Specification
Model	MPL-B520K-MK74AA
Brand	Allen-Bradley
Product Family	MP-Series
Product Series	MPL Low-Inertia Servo Motors
Product Type	Rotary AC servo motor
Motor Construction	Low-inertia brushless permanent-magnet servo
Voltage Class	460 V AC
Maximum Speed	4000 rpm
Rated Output Speed	Approx. 3500 rpm
Continuous Stall Torque	10.7 N·m
Peak Stall Torque	23.2 N·m
Rated Continuous Power	3.5 kW
Rotor Inertia	0.000897 kg·m²
Feedback	Multi-turn absolute
Feedback Resolution	Sin/Cos, 1024 cycles/rev
Feedback Protocol	Hiperface
Shaft	Keyless
Shaft Key	No
Shaft Seal	No standard shaft seal
Brake	24 V DC integral brake
Connector	SpeedTEC DIN
Connector Direction	Right-angle
Connector Rotation	Approx. 180°
Frame Size	165 mm
Frame Size	6.50 in
Magnetic Stack	50.8 mm
Magnetic Stack	2.00 in
Mounting	IEC metric
Mounting Holes	Free mounting holes / Type FF
Approximate Motor Weight	13.9 kg
Approximate Motor Weight	30.6 lb
Typical Applications	Packaging, assembly, indexing, material handling, positioning, vertical axes, printing, converting and automated machinery
Main Advantage	Combination of low inertia, high speed, absolute feedback and integral brake
Main Mechanical Feature	Keyless shaft
Main Holding Feature	24 V DC brake

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25. Conclusion

The MPL-B520K-MK74AA is a medium-power, high-speed, low-inertia servo motor designed for industrial motion-control applications where accurate positioning and dynamic response are important.

Its 4000 rpm maximum speed, 10.7 N·m continuous torque, 23.2 N·m peak torque, and 3.5 kW continuous output provide a useful performance range for automated machinery.

The multi-turn high-resolution absolute encoder supports precise closed-loop motion, while the keyless shaft provides a dedicated mechanical interface for compatible couplings.

The integrated 24 V DC brake is particularly valuable for vertical axes, lifting mechanisms, and other applications where the load needs additional mechanical holding capability.

With its 165 mm frame, 50.8 mm stack length, approximately 13.9 kg weight, right-angle rotatable connector, and low-inertia design, the MPL-B520K-MK74AA is well suited to demanding industrial automation equipment.

For direct replacement work, the most important items to verify are the motor frame and mounting dimensions, shaft configuration, brake wiring, feedback compatibility, connector arrangement, drive compatibility, load inertia, required torque, speed profile, and duty cycle. These factors should be checked together before final motor selection.