MEDIUM-DUTY DOOR OPERATOR-MODEL MH

STANDARD FEATURES
Model Specific:
Work included ­ The electric operator will be Lift-Master Model MH as manufactured by The Chamberlain Group, Inc. Related work ­ Door preparation, miscellaneous or structural metal work, field electrical wiring, wire, conduit, fuses and disconnect switches are in the scope of work of other divisions or trades.

Product:
Supply Model MH, medium-duty, cUL listed, belt drive hoist type operator(s) rated 1/2 H.P., ___ Volts, ___ Phase.

General:
Provide cUL listed electric door operator assembly of size and capacity recommended by door manufacturer; complete with electric motor and factory-prewired motor controls, emergency manual chain hoist mechanism, positive locking mechanical brake, 3-button open/close/stop control station, conduit and wiring from control to motor and accessories required for proper operation.

Electric Motor:
Motor shall be high starting toque 1/2 H.P. rated for a maximum capacity of 12 cycles per hour, protected against overload by an internal automatic reset thermal overload device.

Control Circuit:
24V NEC Class 2 Circuit with a 20 VA transformer.

Frame and Reduction:
Primary speed reduction shall be heavy-duty 4L V-belt and #41 chain and sprocket reduced secondary. Operator shall be equipped with an adjustable friction clutch, solenoid brake and floor level disconnect and manual chain hoist mechanism. Output and door driven sprocket shall be provided with the operator. Operator shall be capable of driving the door at a speed of approximately 8 to 9 inches per second.

Limit Switches:
Fully adjustable, driven linear type limit switch mechanism shall synchronize the operator with the door. Low friction nylon limit nuts fitted on threaded steel shaft, rotating on oilite self-lubricating bronze bushings. The motor shall be removable without affecting the limit switch settings.

Execution:
Install the motor operator in accordance with Lift-Master instructions and standards and in compliance with applicable federal, state or local regulations.

Warranty:
Lift-Master Commercial Door Operators and accessories shall be warranted to be free of any defect in materials and workmanship for a period of two years.