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Allen-Bradley MPL-B320P-SK74AA Servo Motor

1. Product Overview

The Allen-Bradley MPL-B320P-SK74AA is a high-performance, low-inertia brushless AC rotary servo motor designed for demanding industrial motion-control applications.

It belongs to the MPL Low-Inertia Servo Motor Series and is configured for the 460 V class, with a 100 mm frame, 50.8 mm magnet stack, 5000 rpm rated speed, single-turn high-resolution absolute feedback, a keyless shaft extension, a right-angle SpeedTEC DIN connector, and an integrated 24 V DC holding brake.

The B320P configuration provides approximately 1.5 kW of continuous output power, 3.05 Nm of continuous torque, and 7.91 Nm of peak torque. This combination makes it suitable for servo axes that require fast acceleration, repeated positioning, rapid speed changes, and accurate closed-loop motion.

Compared with a conventional induction motor, this type of servo motor is designed specifically for controlled motion rather than simply continuous rotation. The encoder continuously provides position and speed feedback to the servo drive, allowing the complete motion system to regulate the motor according to the machine’s programmed movement profile.

The SK74AA configuration is especially useful where a keyless shaft and integrated 24 V DC holding brake are both required. The keyless shaft is suited to compatible clamping-type couplings, while the brake can provide mechanical holding when the servo axis is stopped or servo power is removed, subject to the machine’s safety and load requirements.

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2. Brand and Product Series

Item	Specification
Brand	Allen-Bradley
Product Series	MPL Low-Inertia Servo Motor Series
Product Family	MP-Series MPL Servo Motors
Model	MPL-B320P-SK74AA
Motor Type	Brushless AC Rotary Servo Motor
Voltage Configuration	460 V
Voltage Class	400 V AC
Frame Size	100 mm
Magnet Stack	50.8 mm
Rated Speed	5000 rpm
Maximum Speed	5000 rpm
Continuous Output Power	1.5 kW
Continuous Output Torque	3.05 Nm
Peak Output Torque	7.91 Nm
Feedback	Absolute single-turn high-resolution encoder
Feedback Resolution	1024 Sin/Cos cycles/rev
Feedback Protocol	Hiperface
Shaft	Keyless shaft extension
Brake	24 V DC holding brake
Connector	SpeedTEC DIN
Connector Orientation	Right angle
Connector Rotation	180° rotatable
Mounting	IEC metric flange
Shaft Seal	No
Approx. Weight	4.54 kg
Approx. Physical Envelope	About 307 × 203 × 239 mm; verify the mechanical drawing before final installation

The MPL series is a low-inertia servo motor family intended for applications where dynamic response, speed, positioning accuracy, and compact mechanical construction are important.

The MPL-B320P-SK74AA occupies a useful middle range within the MPL family. It is larger and more powerful than smaller B310P configurations while remaining more compact than higher-torque B330P, B420P, and B430P configurations.

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3. Model Number Explanation

The model number MPL-B320P-SK74AA contains several pieces of configuration information.

Model Code	Meaning	Configuration
MPL	Product family	Low-Inertia Servo Motor
B	Voltage configuration	460 V
3	Frame designation	100 mm
20	Magnet stack designation	50.8 mm
P	Speed designation	5000 rpm
S	Feedback designation	Single-turn high-resolution encoder
K	Shaft designation	Keyless shaft extension
7	Connector designation	SpeedTEC DIN, right angle, 180° rotatable
4	Brake designation	24 V DC brake
AA	Configuration suffix	Standard configuration

This model coding is useful when comparing similar motors.

For example, the SK72AA version is closely related to the SK74AA, but the SK72AA does not have the integrated 24 V DC brake. The SJ74AA version changes the shaft arrangement from keyless to keyed while retaining the brake.

Therefore, the complete catalog number should always be checked when selecting a replacement motor. Two motors may have the same frame, stack length, speed, and power but still have different mechanical interfaces or brake configurations.

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4. Main Technical Parameters

Parameter	MPL-B320P-SK74AA
Model	MPL-B320P-SK74AA
Brand	Allen-Bradley
Series	MPL Low-Inertia Servo Motor
Motor Type	Brushless AC Rotary Servo Motor
Armature Voltage	460 V
Voltage Class	400 V AC
Rated Speed	5000 rpm
Maximum Speed	5000 rpm
Continuous Rated Power	1.5 kW
Continuous Output Torque	3.05 Nm
Peak Output Torque	7.91 Nm
Rotor Inertia	9.2 × 10⁻⁵ kg·m²
Frame Size	100 mm
Magnet Stack Length	50.8 mm
Feedback Type	Absolute single-turn
Feedback Resolution	Sin/Cos, 1024 cycles/rev
Feedback Protocol	Hiperface
Shaft Configuration	Keyless
Shaft Seal	No
Brake	24 V DC holding brake
Connector	SpeedTEC DIN Type M7
Connector Style	Right-angle
Connector Rotation	180° rotatable
Mounting	Metric flange mount
Maximum Operating Temperature	40 °C
Approx. Dimensions	307 × 203 × 239 mm
Approx. Weight	4.54 kg
Mounting Hole Style	Free mounting holes, Type FF

The technical data identifies the motor as a 5000 rpm, 1.5 kW low-inertia servo motor with 3.05 Nm continuous torque and 7.91 Nm peak torque. The technical configuration specifies a single-turn absolute encoder, 1024 Sin/Cos cycles per revolution, Hiperface feedback, keyless shaft, and 24 V DC brake.

The exact model is listed at approximately 4.54 kg. The dimensional envelope should be treated as an installation-planning value rather than a substitute for the final mechanical drawing, particularly because connector orientation and installation hardware can affect the required machine clearance.

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5. Electrical and Performance Characteristics

The MPL-B320P-SK74AA provides 1.5 kW of continuous rated output power.

Its continuous output torque is approximately 3.05 Nm, while the peak torque capability is approximately 7.91 Nm. The difference between continuous and peak torque is important because servo applications frequently require short bursts of additional torque during acceleration, deceleration, indexing, or rapid changes in machine load.

The motor is rated for 5000 rpm, making it suitable for high-speed motion applications.

At the same time, the low-inertia rotor allows the motor to respond quickly to changes in commanded speed. This combination of high speed and relatively low rotor inertia is one of the major characteristics of the MPL product family.

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6. Torque and Speed Parameters

Performance Parameter	Value
Model	MPL-B320P-SK74AA
Continuous Power	1.5 kW
Continuous Torque	3.05 Nm
Peak Torque	7.91 Nm
Rated Speed	5000 rpm
Maximum Speed	5000 rpm
Rotor Inertia	0.000092 kg·m²
Frame Size	100 mm
Magnet Stack	50.8 mm
Brake	24 V DC
Approx. Dimensions	307 × 203 × 239 mm
Approx. Weight	4.54 kg

The 3.05 Nm continuous torque is the more important figure for determining whether the motor can handle the machine’s normal operating load.

The 7.91 Nm peak torque should be considered when calculating acceleration, deceleration, indexing, short-duration overload, and other dynamic portions of the motion profile.

A correct motor selection should therefore be based on the complete motion cycle rather than simply comparing peak torque values.

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7. Low-Inertia Servo Motor Design

The MPL-B320P-SK74AA is designed as a low-inertia servo motor.

Low rotor inertia is particularly useful in machines that frequently change speed. When a servo motor accelerates and decelerates repeatedly, the motor must overcome both the inertia of the driven load and its own rotor inertia.

Reducing unnecessary motor inertia can improve dynamic response and can make it easier for the servo system to follow rapid motion commands.

This characteristic is useful in packaging machines, indexing systems, automated assembly equipment, converting machines, printing machinery, and other high-cycle equipment.

The motor’s approximate rotor inertia is 9.2 × 10⁻⁵ kg·m² in the specific technical data for this configuration.

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8. Feedback System

The MPL-B320P-SK74AA uses an absolute single-turn high-resolution encoder.

The specified feedback resolution is 1024 Sin/Cos cycles per revolution, and the feedback protocol is Hiperface.

The feedback system provides the servo drive with information about motor position and rotational movement.

This is important for applications where the motor must stop at precise locations, follow a programmed speed profile, synchronize with another axis, or repeatedly return to the same position.

The single-turn configuration should be distinguished from multi-turn encoder versions. If the machine needs absolute position information across multiple revolutions, a multi-turn configuration may be more appropriate.

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9. Keyless Shaft Configuration

The K in the SK74AA designation indicates the keyless shaft extension.

This configuration is intended for use with compatible shaft couplings or clamping systems that do not depend on a traditional shaft key.

A keyless connection can provide a clean mechanical interface and can be particularly convenient for applications where precision couplings are used.

However, the coupling must be correctly matched to the shaft diameter, shaft length, permissible radial load, permissible axial load, clamping requirements, and operating speed.

The keyless shaft configuration also means that the SK74AA should not automatically be treated as a direct mechanical replacement for a keyed-shaft B320P motor.

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10. Integrated 24 V DC Brake

One of the most important characteristics of the MPL-B320P-SK74AA is its 24 V DC holding brake.

The brake provides a mechanical holding function when the motor is stopped, making the configuration useful for applications where the load needs to remain mechanically restrained when servo power is removed.

This can be especially useful for vertical or inclined axes, positioning systems, lifting mechanisms, and other applications where the machine cannot safely rely solely on motor torque to maintain position.

The brake should not, however, be treated as a substitute for the machine’s complete safety system. Brake control, stopping behavior, gravity loads, emergency-stop requirements, and mechanical safety arrangements should all be considered during machine design.

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11. Brake Applications

The integrated brake can be particularly useful in the following types of equipment:

Application	Potential Brake Requirement
Vertical positioning axis	High
Lift mechanism	High
Vertical transfer unit	High
Z-axis positioning	Often required
Inclined conveyor	Depends on load
Horizontal conveyor	Often unnecessary
Rotary indexing table	Depends on mechanical design
Packaging axis	Application dependent
Assembly axis	Application dependent
Inspection stage	Application dependent

The brake-equipped SK74AA configuration provides an additional mechanical holding function that the SK72AA version does not provide.

For applications involving suspended loads, the exact braking and safety design should always be evaluated separately.

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12. Connector Configuration

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

The connector can be rotated through approximately 180°, giving the installer greater flexibility when routing motor cables.

This feature can be valuable in compact automation equipment.

A servo motor may be installed inside a machine frame with limited clearance around the motor housing. A fixed connector orientation can make cable routing difficult, whereas a rotatable connector allows the cable direction to be adapted to the available space.

Proper cable bend radius should still be maintained, and the connector should not be used as a mechanical support point for the cable.

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13. Mechanical Mounting

The MPL-B320P-SK74AA uses a metric flange mounting configuration with a 100 mm frame.

The published configuration specifies free mounting holes, Type FF.

The motor should be mounted on a clean, rigid, properly aligned machine surface.

The mounting bolts should secure the motor without forcing the motor shaft into alignment with the driven equipment. Shaft and coupling alignment should be established mechanically rather than corrected by tightening mounting hardware.

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14. Product Introduction

The MPL-B320P-SK74AA is designed for machine builders who need a combination of high rotational speed, moderate continuous torque, dynamic response, precision feedback, and mechanical holding capability.

Its 100 mm frame size makes it relatively compact for a motor capable of 1.5 kW continuous output and 5000 rpm operation.

The 50.8 mm magnet stack provides a relatively short motor configuration compared with longer versions of the same general family.

This makes the motor suitable for equipment where the motor must deliver substantial dynamic performance without occupying excessive machine space.

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15. Main Product Advantages

Advantage	Description
Model	MPL-B320P-SK74AA
High-Speed Performance	5000 rpm rated speed
Continuous Power	1.5 kW
Continuous Torque	3.05 Nm
Peak Torque	7.91 Nm
Low Rotor Inertia	Approx. 9.2 × 10⁻⁵ kg·m²
High-Resolution Feedback	1024 Sin/Cos cycles/rev
Absolute Feedback	Single-turn encoder
Keyless Shaft	Suitable for compatible clamping couplings
Integrated Brake	24 V DC holding brake
Flexible Connector	180° rotatable right-angle connector
Compact Frame	100 mm
Compact Stack	50.8 mm
Metric Mounting	IEC metric flange
Industrial Servo Construction	Brushless AC servo design
Approx. Dimensions	307 × 203 × 239 mm
Approx. Weight	4.54 kg

The strongest practical advantage of this particular configuration is the combination of a keyless shaft and integrated brake.

That combination distinguishes the SK74AA from the no-brake SK72AA and from keyed-shaft versions such as the SJ74AA.

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16. Typical Applications

Packaging Machinery

The MPL-B320P-SK74AA is well suited to packaging equipment where motion must be accurately synchronized with the machine cycle.

Typical applications can include indexing, product positioning, film feeding, sealing mechanisms, cutting mechanisms, rotary motion, and synchronized conveyor sections.

The 5000 rpm speed capability can support rapid machine cycles, while the servo feedback system allows the controller to regulate position and speed.

The integrated brake can also be useful when a machine axis needs to remain mechanically held during a stopped condition.

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Automated Assembly

Automated assembly equipment often requires several servo axes to move quickly and repeatedly.

The MPL-B320P-SK74AA can be used for positioning slides, rotary indexing units, transfer mechanisms, assembly heads, tooling axes, and other motion-control functions.

Its low-inertia design is useful where the axis must accelerate and decelerate repeatedly.

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Material Handling

The motor can be used in automated conveyors, indexing mechanisms, roller systems, transfer units, and positioning equipment.

The servo drive can regulate acceleration and deceleration instead of simply turning the motor on and off.

For inclined or vertical material-handling applications, the integrated brake may provide an additional holding function, subject to proper machine and safety design.

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Printing Machinery

Printing equipment often requires synchronized motion between rollers, feeders, cutters, and material-handling mechanisms.

The high-speed servo motor can be used for roller drives and other controlled rotary axes.

The encoder provides feedback for accurate speed regulation and positioning.

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Converting Machinery

Converting machines used for paper, film, foil, labels, and other flexible materials often contain several servo-controlled axes.

Possible applications include feeding, indexing, cutting, rewinding, positioning, and tension-related motion.

The low-inertia characteristics can be useful when the axis frequently changes speed.

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Labeling Machines

High-speed labeling machines require synchronization between the product conveyor, label feed, cutting system, and other mechanical sections.

The MPL-B320P-SK74AA can be used for controlled label feeding and indexing.

The servo’s feedback system supports repeatable motion, while the high-speed rating can accommodate rapid machine cycles.

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Electronics Manufacturing

Electronics manufacturing equipment frequently requires controlled and repeatable positioning.

The motor can be used for transfer mechanisms, positioning stages, indexing tables, inspection systems, and automated handling equipment.

The low-inertia design can be advantageous where the axis repeatedly moves short distances at high acceleration.

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Inspection and Test Equipment

Inspection equipment may require servo-driven stages to position cameras, sensors, fixtures, test heads, or products.

The MPL-B320P-SK74AA can provide the controlled movement needed for these systems.

The absolute single-turn encoder provides feedback to the servo system, helping maintain repeatable positioning.

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17. Application Selection Guide

Application Requirement	MPL-B320P-SK74AA
High-speed rotation	Well suited
5000 rpm operation	Yes
1.5 kW continuous power	Yes
3.05 Nm continuous torque	Yes
Short-duration high torque	Up to 7.91 Nm peak
Repeated acceleration/deceleration	Well suited
Precision positioning	Well suited
Horizontal servo axis	Well suited
Vertical axis	Suitable when brake and safety requirements are properly designed
Keyless coupling	Yes
Keyed coupling	Not the preferred configuration
Integrated holding brake	Yes
Single-turn absolute feedback	Yes
Multi-turn absolute feedback	No; consider an appropriate multi-turn model
Compact machine design	Suitable
Approx. Dimensions	307 × 203 × 239 mm
Approx. Weight	4.54 kg

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18. Five Closely Related Models

The following five models are closely related to the MPL-B320P-SK74AA and can be considered when different shaft, brake, or feedback requirements exist.

Model	Speed	Power	Continuous Torque	Feedback	Shaft	Brake	Dimensions	Weight
MPL-B320P-SK74AA	5000 rpm	1.5 kW	3.05 Nm	Single-turn absolute	Keyless	24 V DC	Approx. 307 × 203 × 239 mm	4.54 kg
MPL-B320P-SK72AA	5000 rpm	1.5 kW	3.05 Nm	Single-turn absolute	Keyless	No	Approx. B320P family envelope	Approx. 4 kg class
MPL-B320P-SJ74AA	5000 rpm	1.5 kW	3.05 Nm	Single-turn absolute	Keyed	24 V DC	Approx. B320P family envelope	Approx. 4.54 kg
MPL-B320P-SJ72AA	5000 rpm	1.5 kW	3.05 Nm	Single-turn absolute	Keyed	No	Approx. B320P family envelope	Approx. 4.5 kg
MPL-B320P-MJ74AA	5000 rpm	1.5 kW	3.05 Nm	Multi-turn absolute	Keyed	24 V DC	Approx. B320P family envelope	Approx. 4.5 kg

The SK72AA is the closest configuration when the keyless shaft is required but the brake is not needed.

The SJ74AA is a close alternative when the machine uses a keyed shaft rather than a keyless coupling.

The MJ74AA becomes relevant when the machine requires multi-turn absolute feedback together with a keyed shaft and brake.

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19. Related Model Comparison

Feature	MPL-B320P-SK74AA	MPL-B320P-SK72AA	MPL-B320P-SJ74AA	MPL-B320P-SJ72AA	MPL-B320P-MJ74AA
Voltage	460 V	460 V	460 V	460 V	460 V
Frame	100 mm	100 mm	100 mm	100 mm	100 mm
Stack	50.8 mm	50.8 mm	50.8 mm	50.8 mm	50.8 mm
Speed	5000 rpm	5000 rpm	5000 rpm	5000 rpm	5000 rpm
Power	1.5 kW	1.5 kW	1.5 kW	1.5 kW	1.5 kW
Continuous Torque	3.05 Nm	3.05 Nm	3.05 Nm	3.05 Nm	3.05 Nm
Peak Torque	7.91 Nm	7.91 Nm	7.91 Nm	7.91 Nm	7.91 Nm
Feedback	Single-turn	Single-turn	Single-turn	Single-turn	Multi-turn
Shaft	Keyless	Keyless	Keyed	Keyed	Keyed
Brake	24 V DC	No	24 V DC	No	24 V DC
Approx. Dimensions	307 × 203 × 239 mm	Family envelope	Family envelope	Family envelope	Family envelope
Approx. Weight	4.54 kg	Approx. 4 kg class	Approx. 4.5 kg	Approx. 4.5 kg	Approx. 4.5 kg

This comparison demonstrates why the complete model number is important.

The basic B320P motor rating remains similar across these configurations, but the shaft, brake, and feedback arrangement changes the practical application of each motor.

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20. Five Representative Same-Brand Models

The following are five representative Allen-Bradley models from the same general servo-motor family or closely related MPL configurations.

They are presented as comparison choices rather than as a ranking.

Model	Series	Speed	Power	Continuous Torque	Feedback	Shaft	Brake	Dimensions	Weight
MPL-B310P-MJ74AA	MPL Low Inertia	5000 rpm	Approx. 0.77 kW	Approx. 1.58 Nm	Multi-turn absolute	Keyed	24 V DC	Approx. 100 mm frame	Approx. 2.7 kg
MPL-B320P-MK74AA	MPL Low Inertia	5000 rpm	Approx. 1.5 kW	Approx. 3.05 Nm	Multi-turn absolute	Keyless	24 V DC	Approx. 100 mm frame	Approx. 4.5 kg
MPL-B330P-MK74AA	MPL Low Inertia	5000 rpm	Approx. 1.8 kW	Approx. 4.18 Nm	Multi-turn absolute	Keyless	24 V DC	Approx. 100 mm frame, longer stack	Approx. 6.1 kg
MPL-B420P-MJ74AA	MPL Low Inertia	5000 rpm	Approx. 1.9 kW	Approx. 4.74 Nm	Multi-turn absolute	Keyed	24 V DC	Approx. 115 mm frame	Approx. 6.4 kg
MPL-B430P-MJ72AA	MPL Low Inertia	5000 rpm	Approx. 2.2 kW	Approx. 6.55 Nm	Multi-turn absolute	Keyed	No	Approx. 130 mm frame	Approx. 9.2 kg

The MPL family performance data shows the progression from smaller B310P configurations through B320P, B330P, B420P, and B430P motors. As frame or stack size increases, continuous power and torque also increase.

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21. MPL Family Performance Comparison

Model Family	Speed	Continuous Power	Continuous Torque	Peak Torque	Rotor Inertia	Approx. Weight	Dimensions
MPL-B310P	5000 rpm	0.77 kW	1.58 Nm	3.61 Nm	0.000044 kg·m²	Approx. 2.4–2.7 kg	100 mm frame
MPL-B320P	5000 rpm	1.5 kW	3.05 Nm	7.91 Nm	0.000078 kg·m² family value	Approx. 4.5 kg class	100 mm frame
MPL-B330P	5000 rpm	1.8 kW	4.18 Nm	11.1 Nm	0.00012 kg·m²	Approx. 6.1 kg	100 mm frame
MPL-B420P	5000 rpm	1.9 kW	4.74 Nm	13.5 Nm	0.00026 kg·m²	Approx. 6.4 kg	Approx. 115 mm frame
MPL-B430P	5000 rpm	2.2 kW	6.55 Nm	19.8 Nm	0.00038 kg·m²	Approx. 9.2 kg	Approx. 130 mm frame

The B320P is positioned between the smaller B310P and the larger B330P/B420P/B430P configurations.

For many machines, this makes the B320P a practical choice when the B310P does not provide enough torque but a larger motor would add unnecessary size or mass.

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22. MPL-B320P-SK74AA Versus MPL-B320P-SK72AA

Feature	MPL-B320P-SK74AA	MPL-B320P-SK72AA
Speed	5000 rpm	5000 rpm
Continuous Power	1.5 kW	1.5 kW
Continuous Torque	3.05 Nm	3.05 Nm
Peak Torque	7.91 Nm	7.91 Nm
Feedback	Single-turn absolute	Single-turn absolute
Shaft	Keyless	Keyless
Brake	24 V DC	No brake
Connector	SpeedTEC DIN	SpeedTEC DIN
Connector	Right-angle, 180° rotatable	Right-angle, 180° rotatable
Frame	100 mm	100 mm
Stack	50.8 mm	50.8 mm
Approx. Weight	4.54 kg	Approx. 4 kg class
Dimensions	Approx. 307 × 203 × 239 mm	Similar B320P envelope

The principal difference between these two configurations is the integrated brake.

If the machine requires mechanical holding at the motor, the SK74AA configuration provides that additional function.

If the machine does not require a holding brake, the SK72AA can provide a simpler no-brake configuration.

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23. MPL-B320P-SK74AA Versus MPL-B320P-SJ74AA

Feature	MPL-B320P-SK74AA	MPL-B320P-SJ74AA
Voltage	460 V	460 V
Speed	5000 rpm	5000 rpm
Power	1.5 kW	1.5 kW
Continuous Torque	3.05 Nm	3.05 Nm
Peak Torque	7.91 Nm	7.91 Nm
Feedback	Single-turn absolute	Single-turn absolute
Shaft	Keyless	Keyed
Brake	24 V DC	24 V DC
Frame	100 mm	100 mm
Stack	50.8 mm	50.8 mm
Connector	SpeedTEC DIN	SpeedTEC DIN
Approx. Weight	4.54 kg	Approx. 4.54 kg
Approx. Dimensions	307 × 203 × 239 mm	Similar B320P envelope

The principal mechanical difference is the shaft.

The SK74AA uses a keyless shaft, while the SJ74AA uses a keyed shaft.

The electrical and performance characteristics are closely related, but the coupling arrangement must match the motor shaft configuration.

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24. Servo Drive Compatibility

The technical specification for the MPL-B320P-SK74AA identifies compatibility with several motion-control drive families, including Kinetix 5500, Kinetix 6200/6500, Kinetix 6000, Kinetix 300, Kinetix 350, Kinetix 2000, Kinetix 7000, and Ultra 3000 families.

The exact drive selection should still be confirmed against the specific machine configuration.

The motor, servo drive, feedback cable, motor power cable, brake circuit, and mechanical load should be treated as one complete motion-control system.

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25. Installation Requirements

The first installation requirement is correct mechanical mounting.

The motor flange must be securely mounted to a rigid machine surface.

The second requirement is proper shaft alignment.

Because the SK74AA has a keyless shaft, the coupling must be selected specifically for a keyless servo shaft.

The third requirement is cable management.

The right-angle connector provides flexibility, but the cable should still have an appropriate bend radius and should not be exposed to excessive pulling or twisting forces.

The fourth requirement is brake control.

The 24 V DC brake must be integrated into the machine’s control architecture correctly.

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26. Brake Control Considerations

The brake should generally be considered a holding device, not simply an operating torque source.

During machine operation, servo torque is normally responsible for controlling the axis.

When the machine reaches a condition where the brake needs to engage, the servo system and brake control should be coordinated appropriately.

For vertical axes, the timing between servo torque and brake engagement can be especially important.

The exact brake control strategy should be determined from the machine’s load, stopping behavior, safety requirements, and control system.

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27. Maintenance Considerations

The MPL-B320P-SK74AA does not require the same type of routine maintenance as a conventional mechanical transmission, but regular inspection remains important.

The mounting bolts, coupling, shaft connection, motor cable, feedback connector, brake wiring, and surrounding machine structure should be inspected periodically.

Abnormal vibration should be investigated rather than ignored.

Potential causes can include coupling misalignment, excessive shaft loading, mechanical resonance, incorrect servo tuning, damaged bearings, cable problems, or changes in the driven load.

The motor’s operating temperature should also be monitored.

A sudden increase in temperature may indicate excessive continuous torque demand, inadequate machine cooling, excessive acceleration, mechanical friction, or a servo-control problem.

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28. Keyless Shaft Advantages

The keyless shaft configuration can provide several practical advantages when used with an appropriate coupling.

It eliminates the need for a traditional shaft key and allows the machine designer to use compatible clamping-type couplings.

This can be particularly convenient for precision positioning systems.

The keyless arrangement can also simplify certain coupling installations because the coupling is secured through its clamping mechanism rather than depending on a traditional key-and-keyway connection.

However, the coupling must be correctly installed and tightened according to its manufacturer’s requirements.

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29. Integrated Brake Advantages

The integrated 24 V DC brake gives the SK74AA an important advantage for applications where the axis needs to remain mechanically held.

This is particularly relevant to vertical positioning systems.

For example, a vertical machine axis may need to remain in position when servo power is removed. Without a holding mechanism, gravity could cause the axis to move.

A brake-equipped motor provides an additional mechanical holding function that can help address this requirement.

The brake should still be incorporated into the machine’s complete safety design and should not be treated as the only protective measure.

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30. High-Speed Operation Advantages

The 5000 rpm rating makes the motor suitable for high-speed rotary motion.

High speed can be valuable in applications where machine throughput is directly related to rotational speed.

Examples include rollers, indexing mechanisms, feeding systems, packaging components, and high-cycle automated equipment.

However, the actual operating speed should be selected according to the load, inertia, bearing requirements, coupling rating, mechanical balance, and machine duty cycle.

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31. Compact Mechanical Design

The 100 mm frame and 50.8 mm magnet stack give the B320P a relatively compact physical configuration.

For machine builders, compact motor dimensions can be useful because the motor is often installed inside a machine frame where available space is limited.

The right-angle connector also helps reduce the space needed for cable routing behind the motor.

The approximate motor envelope should be used for initial machine layout, while the final production design should use the exact mechanical drawing and connector clearance requirements.

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32. Application Examples

Machine Type	Typical Servo Function	Suitability
Packaging machine	Indexing / feeding	High
Cartoning equipment	Positioning / transfer	High
Labeling machine	Label feeding	High
Printing machine	Roller synchronization	High
Converting machine	Feeding / cutting	High
Automated assembly	Positioning / indexing	High
Inspection machine	Stage movement	High
Material handling	Conveyor / transfer	High
Vertical positioning system	Z-axis movement	High when brake and safety design are appropriate
Rotary indexing table	Indexing	High
Electronics production	Transfer / positioning	High
Test equipment	Precision movement	High

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33. Engineering Selection Checklist

Selection Item	MPL-B320P-SK74AA Requirement
Model	MPL-B320P-SK74AA
Brand	Allen-Bradley
Series	MPL Low-Inertia
Voltage	460 V
Continuous Power	1.5 kW
Continuous Torque	3.05 Nm
Peak Torque	7.91 Nm
Rated Speed	5000 rpm
Feedback	Absolute single-turn
Feedback Resolution	1024 Sin/Cos cycles/rev
Feedback Protocol	Hiperface
Shaft	Keyless
Brake	24 V DC
Frame	100 mm
Stack	50.8 mm
Connector	SpeedTEC DIN
Connector Direction	Right angle
Connector Adjustment	180°
Approx. Dimensions	307 × 203 × 239 mm
Approx. Weight	4.54 kg
Mounting	IEC metric flange
Operating Temperature	Up to approximately 40 °C

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34. Important Replacement Considerations

When replacing an existing servo motor with an MPL-B320P-SK74AA, the complete model number should be compared.

The following items should be checked individually:

1. Voltage class.
2. Continuous power.
3. Continuous torque.
4. Peak torque.
5. Rated speed.
6. Feedback type.
7. Feedback protocol.
8. Shaft type.
9. Brake availability.
10. Connector style.
11. Mounting dimensions.
12. Motor weight.
13. Cable compatibility.
14. Servo-drive compatibility.
15. Mechanical coupling compatibility.

A motor with the same basic B320P designation may still have a different shaft or brake arrangement.

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35. Overall Product Advantages

The Allen-Bradley MPL-B320P-SK74AA combines several characteristics that are valuable in industrial servo applications.

Its 5000 rpm speed supports high-cycle machine operation.

Its 1.5 kW continuous power provides a useful output level for medium-duty motion axes.

Its 3.05 Nm continuous torque and 7.91 Nm peak torque provide both normal operating capability and short-duration dynamic torque.

Its low-inertia rotor supports rapid acceleration and deceleration.

Its single-turn absolute encoder provides accurate feedback for closed-loop motion control.

Its keyless shaft is suited to compatible clamping couplings.

Its 24 V DC holding brake provides a useful mechanical holding function for applications where the axis needs to remain stationary after servo power is removed.

Its 180° rotatable right-angle SpeedTEC DIN connector can simplify cable routing in compact machines.

Its 100 mm frame and 50.8 mm stack provide a relatively compact mechanical package for its power and speed class.

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36. Final Technical Summary

Category	Specification
Model	MPL-B320P-SK74AA
Brand	Allen-Bradley
Series	MPL Low-Inertia Servo Motor Series
Product Type	Brushless AC Rotary Servo Motor
Voltage	460 V
Voltage Class	400 V AC
Frame Size	100 mm
Magnet Stack	50.8 mm
Rated Speed	5000 rpm
Maximum Speed	5000 rpm
Continuous Power	1.5 kW
Continuous Torque	3.05 Nm
Peak Torque	7.91 Nm
Rotor Inertia	9.2 × 10⁻⁵ kg·m²
Feedback	Absolute single-turn
Resolution	1024 Sin/Cos cycles/rev
Protocol	Hiperface
Shaft	Keyless
Shaft Seal	No
Brake	24 V DC holding brake
Connector	SpeedTEC DIN
Connector Orientation	Right angle
Connector Rotation	180°
Mounting	IEC metric flange
Mounting Holes	Free mounting holes, Type FF
Maximum Operating Temperature	40 °C
Approx. Dimensions	307 × 203 × 239 mm
Approx. Weight	4.54 kg

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37. Final Product Description

The Allen-Bradley MPL-B320P-SK74AA is a 5000 rpm, 1.5 kW low-inertia AC rotary servo motor belonging to the MPL Low-Inertia Servo Motor Series.

It is configured for 460 V operation, uses a 100 mm frame and 50.8 mm magnet stack, and provides approximately 3.05 Nm continuous torque and 7.91 Nm peak torque. Its feedback system is an absolute single-turn high-resolution encoder with 1024 Sin/Cos cycles per revolution and Hiperface protocol.

The motor uses a keyless shaft extension, making it suitable for compatible clamping-type couplings. It also incorporates a 24 V DC holding brake, which makes this configuration particularly useful for machine axes where mechanical holding is required.

The right-angle SpeedTEC DIN connector with 180° rotational flexibility is another practical feature for industrial machine construction, especially where cable-routing space is restricted.

Typical applications include packaging machinery, automated assembly equipment, material-handling systems, printing machinery, converting equipment, labeling machinery, electronics manufacturing equipment, inspection systems, indexing mechanisms, positioning stages, and other automated production equipment.

For engineering selection, the most important parameters are the 1.5 kW continuous power, 3.05 Nm continuous torque, 7.91 Nm peak torque, 5000 rpm speed, single-turn absolute feedback, keyless shaft, 24 V DC brake, 100 mm frame, 50.8 mm stack, approximately 4.54 kg weight, and the required installation envelope.

The main distinction between this model and the closely related MPL-B320P-SK72AA is the integrated brake. The SK74AA includes the 24 V DC holding brake, while the SK72AA is the no-brake version. The distinction between the SK74AA and SJ74AA is primarily the shaft configuration: the SK74AA uses a keyless shaft, while the SJ74AA uses a keyed shaft.

For a machine requiring high-speed servo motion, low rotor inertia, absolute single-turn feedback, a keyless shaft, and an integrated holding brake, the MPL-B320P-SK74AA provides a comprehensive configuration within the B320P motor class.