The LiftMaster MJ Medium-Duty Logic Jackshaft Operator is a commercial-grade door operator designed for smaller and lighter rolling steel doors, grilles, and high or vertical-lift sectional doors in mid-range duty cycle environments.

This operator is engineered for dependable performance in commercial facilities where controlled operation and reliability are essential. It supports wall-mounted installation and is suitable for applications requiring up to 12 cycles per hour and fewer than 50 cycles per day.

The MJ series features a mechanical limit system, solid-state logic control board, and emergency disconnect for manual operation, ensuring safe and consistent door control in daily commercial use.

Specifications Radio receiver

• Security+R 315 MHz radio receiver

• Supports up to 23 Security+ remote controls and unlimited DIP switch remotes 

Electrical

• Single-phase 115V

• Control circuit: 24V NEC Class 2

Drive system

• First-stage heavy-duty 4L V-belt

• Second and third stages: #48 chain

Bearings / bushings

• Heavy-duty oil-filled bushings 

Brake

• Heavy-duty solenoid-actuated brake 

Construction

• NEMA 1 electrical enclosure

• Heavy-duty 11-gauge steel frame

• Baked-on powder coat finish

• Drilled and pinned reduction sprockets

Warranty

• 2-year limited warranty

Installation Features

• Universal mounting: Yes

• Maximum door height: 14 ft standard (additional capability available)

• Maximum door width: 22 ft

• Maximum allowable door area: 320 sq. ft.

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Price available upon request. Contact us for a custom quote.