Description
Allen-Bradley 1326AB-B720F-M2K7LS
Product Introduction
The Allen-Bradley 1326AB-B720F-M2K7LS is a high-power AC permanent-magnet servo motor from the Bulletin 1326AB Torque Plus series. It is designed for machine-axis applications requiring controlled acceleration, positioning and speed regulation rather than simple fixed-speed motor operation. The B720F frame configuration is specified for 460/380 VAC operation, 5,000 RPM maximum rated speed, 11.7 kW output class, 27.5 A current and a 31.8 Nm torque rating. The motor uses a 194 mm frame and belongs to the larger 1326AB servo range intended for demanding industrial motion applications.
The Allen-Bradley 1326AB-B720F-M2K7LS is distinguished from closely related 1326AB variants by its complete option code. The M2 configuration is associated with multi-turn high-resolution feedback, while the K7 option identifies the larger 41 Nm, 24 VDC brake configuration used across corresponding 1326AB variants. The LS configuration is associated with the IP67/environmental and connector arrangement; published product descriptions identify this exact model as a 460 V, 5,000 RPM, multi-turn high-resolution, brake-equipped, IP67 servo motor with the connector exiting toward the shaft.
For an existing machine, the Allen-Bradley 1326AB-B720F-M2K7LS should be matched by the complete catalog number rather than by the basic B720F frame designation. Allen-Bradley 1326AB motors with the same frame family are available with different feedback types, brake configurations and connector arrangements. Elwood’s current legacy-motor documentation maps the exact Rockwell part number 199861.60 to 1326AB–M2K7LS, confirming that the final suffix represents a specific configuration rather than a generic motor variant.
Technical Specifications
| Parameter | Specification |
|---|---|
| Product Model | 1326AB–M2K7LS |
| Manufacturer | Allen-Bradley / Rockwell Automation |
| Product Family | Bulletin 1326AB Torque Plus |
| Product Type | AC Permanent-Magnet Servo Motor |
| Frame Size | 194 mm |
| Rated Voltage | 460/380 VAC |
| Rated Speed | 5,000 RPM |
| Rated Power | 11.7 kW |
| Approx. Horsepower | 15.7 HP |
| Rated Current | 27.5 A |
| Torque Rating | 31.8 Nm |
| Feedback | Multi-turn high-resolution |
| Brake | 41 Nm, 24 VDC configuration |
| Environmental Protection | IP67 |
| Connector Configuration | Connector exit toward shaft |
| Rockwell Part Number | 199861.60 |
| Mounting | Servo motor flange / machine mounting |
| Motor Technology | Permanent-magnet AC servo |
| Series | 1326AB Torque Plus |
| Lifecycle | Legacy / discontinued product family |
The 11.7 kW, 27.5 A, 31.8 Nm and 5,000 RPM figures are consistently associated with the 1326AB configuration in available technical records. The exact configuration is specifically identified as multi-turn high-resolution feedback, brake-equipped and IP67.
1326AB-B720F-M2K7LS
Main Features and Engineering Considerations
High-Power Servo Construction
The is one of the larger motors in the 1326AB range, using a 194 mm frame. Its 11.7 kW rating places it in applications where a smaller servo motor would not provide sufficient continuous output. The motor is intended to operate with a compatible Allen-Bradley servo drive and feedback system rather than as a conventional induction motor connected directly to a line supply.
5,000 RPM Operation
The 5,000 RPM rating is significant when evaluating the mechanical load. At this speed, coupling, gearbox, lubrication, bearing condition and driven-machine balance become important. Do not select the motor solely by comparing horsepower. The machine’s required continuous torque, peak acceleration torque, speed profile and reflected inertia should all be checked.
Multi-Turn High-Resolution Feedback
The M2 configuration uses multi-turn high-resolution feedback. This is particularly useful where the motion controller needs detailed rotor-position information and where the application requires repeatable positioning. Feedback compatibility must be checked at the drive level; installing a physically similar motor with a different feedback configuration can prevent the drive from operating correctly.
Integrated Holding Brake
The K7 configuration is associated with a 41 Nm, 24 VDC brake. This brake should not automatically be treated as a dynamic stopping brake. In most servo applications, the motor drive performs controlled deceleration while the mechanical brake is primarily used for holding or preventing movement when power is removed. Brake timing and drive sequencing should follow the machine’s safety and motion-control design.
IP67 Construction
The exact model is identified with an IP67 environmental rating. This is useful for machinery exposed to dust and temporary water immersion, but does not mean that every connector, mating cable or shaft seal in the installed assembly automatically has the same protection. The complete motor/cable interface needs to be considered during installation.
Connector Orientation
The exact configuration is associated with the connector exit toward the shaft. This can matter in tight machine enclosures where cable bend radius and connector clearance are limited. A motor with a different connector orientation may be electrically compatible yet mechanically unsuitable.
Legacy Equipment Consideration
The 1326AB series is a legacy Allen-Bradley servo family. Elwood currently lists replacement motors corresponding to the 1326AB series, including the exact Rockwell part number 199861.60. For a maintenance replacement, however, a form-fit-function alternative should still be validated against the existing drive, feedback interface, brake wiring and mechanical mounting.
Application Scenarios
High-Speed Machine Axes
The 5,000 RPM capability makes this motor suitable for high-speed rotary axes where controlled acceleration and positioning are required.
Material Handling
The high power rating and integrated brake can be useful in conveyors, indexing systems and high-inertia material-handling machinery where controlled stopping and mechanical holding are required.
Machine Tools
The multi-turn high-resolution feedback configuration is appropriate for precision motion applications where the controller needs detailed position information.
Packaging Machinery
High-speed indexing, cutting, forming and synchronized rotary mechanisms can use large-frame servo motors such as the where continuous power requirements exceed smaller 1326AB configurations.
Legacy Rockwell Motion Systems
The motor is particularly relevant when maintaining an existing Allen-Bradley 1326AB servo installation and retaining the existing mechanical interface, drive architecture and feedback system is more practical than a complete motion-system migration.
Engineer’s Guide: Field Pitfalls
1. Do not substitute by horsepower alone.
A different 1326AB motor may have the same approximate power but a different feedback system, brake, connector orientation or electrical characteristics.
2. Verify the servo drive.
The motor must be matched to the drive’s supported 1326AB motor configuration. Check motor identification, feedback type, current capacity and drive parameter set before commissioning.
3. Confirm brake voltage and sequencing.
The K7 configuration uses a 24 VDC brake. Verify the machine’s brake supply and make sure the brake-release sequence is coordinated with servo enable and torque production.
4. Check feedback before powering the motor.
A feedback mismatch can produce immediate drive faults or, in an incorrectly configured system, unsafe motion. Confirm the exact feedback interface and cable assembly.
5. Inspect the connector and cable route.
The connector exits toward the shaft on this configuration. Make sure the existing cable has adequate clearance and bend radius and does not contact rotating components.
6. Do not assume covers the complete installation.
The motor’s rating does not eliminate the need for correctly sealed mating connectors, cables and shaft-side installation practices.
7. Check mechanical inertia.
With a high-power servo motor, the motor may be electrically capable of accelerating a load that the mechanical transmission cannot safely tolerate. Coupling, gearbox, shaft and load inertia should be reviewed together.
8. Test legacy motors before critical installation.
For stored or previously installed equipment, insulation resistance, winding condition, shaft/bearing condition, brake operation and feedback performance should be tested before connecting it to production machinery.
Frequently Asked Questions
What is Allen-Brad?
It is an Allen-Bradley Bulletin 1326AB Torque Plus AC permanent-magnet servo motor in the frame configuration. It is specified for 460/380 VAC, 5,000 RPM and 11.7 kW, with multi-turn high-resolution feedback, a 41 Nm 24 VDC brake and protection.
What is the power rating?
The configuration is rated at 11.7 kW, approximately 15.7 HP.
What is the rated speed?
The published specification for the configuration is 5,000 RPM.
What feedback does the use?
The M2 configuration is identified with multi-turn high-resolution feedback. This must be matched to the compatible servo drive and feedback cable/interface.
Does this motor have a brake?
Yes. The K7 configuration is associated with a 41 Nm, 24 VDC brake in the corresponding 1326AB configurations.
Is the motor ?
Yes. The exact configuration is identified as .
still a current Allen-Bradley motor?
The 1326AB series is a legacy product family, and the exact Rockwell part number 199861.60 is documented in legacy replacement-motor listings. When maintaining an existing machine, compatibility with the installed drive and feedback system is more important than simply finding another motor with the same frame size.
Procurement Note
For , specify the complete catalog number and, where possible, request a nameplate photograph before approving a replacement. The important identifiers are , M2, K7, and LS; changing any of these can change the feedback, brake, environmental or mechanical configuration.
The corresponding Rockwell part number is 199861.60. Elwood’s current 1326AB replacement documentation maps this number directly to , which is useful when cross-checking legacy inventory or replacement documentation.
For a used motor, I would require at minimum a winding/insulation test, brake test, feedback verification, shaft/bearing inspection and confirmation that the connector and shaft seal are intact. For a high-value production axis, a static visual inspection alone is not sufficient evidence that a stored 1326AB motor is installation-ready.
