The Liftmaster® Medium-Duty Trolley Operator is designed for use on commercial standard lift sectional doors. Its high-torque industrial 1/2 HP motor provides dependable lift along a high-strength L-rail track featuring an exclusive nylon guiding chain for quieter operation.  A quick-mount header bracket means faster installation. In addition, its featured Auxiliary Reversal System protects the door and operator from damage in case of obstructions.  

FEATURES
Liftmaster® Medium-Duty Trolley Operator

Standard Features:

• Our high-torque industrial 1/2 HP 115V single-phase motor features instant reverse and automatic reset thermal overload. The motor can be removed without affecting limit switch settings.
• A high-strength dual L-rail track features a nylon gliding chain on rail spacers for quieter and smoother operation.
• A quick-mount swivel header bracket is designed for faster installation.
• A 3-button station for OPEN/CLOSE/STOP functions is standard for all operators.  Controls with one, two and three buttons are available.
• An adjustable friction clutch helps protect against damage to the door and operator should the door meet an obstruction. Works in conjunction with the Auxiliary Reversal System.

Safety Features:
The MT features an Auxiliary Reversal System which is designed to protect the door and door operator from damage.  The system detects the slip of the clutch in the event of an obstruction, then immediately reverses the door to full open position. This system is not a substitute for light-beam or other personal safety systems.

Other Features:

• Wiring Type: All operators are factory preset to C2 wiring providing momentary contact to open and stop, with constant contact to close. Momentary contact to close (B2 wiring) can be easily set. The operator is pre-wired to accept a sensing device, photoelectric control, radio controls and most types of access control equipment.
• Operator/Motor Control: Dependable dual relay system (NEMA 1 enclosure).
• Control Circuit: 24V NEC Class 2.
• Drive Reduction: First stage heavy-duty 4L V-belt; second and third stages #48 chain; output on trolley #48 chain.
• Emergency Disconnect: Spring-loaded disconnect for emergency manual operation.
• Construction: NEMA 1 type electrical box, heavy-duty 11-gauge steel frame with baked-on powder coat finish, all reduction sprockets drilled and pinned to shafts.
• Bearings: Heavy-duty, oil filled bearings.
• External Radio Control Terminal: External terminals provide quick, convenient connections for universal radio controls.

OPTIONS
Control Accessories and Options:

• Solenoid Brake: Solenoid actuated brake prevents coasting. Order operator BMT. Standard on 3/4 HP and higher.
• Auto-Reconnect Trolley Assembly: Spring-loaded trolley features nylon inserts for quiet operation and auto-reconnect feature eliminating the need to manually reattach the door arm to the trolley after emergency disconnect.
• Sensing Edge: (Recommended) Designed to sense an obstruction and signal door operator to stop or reverse as desired. Either an electric or pneumatic sensing device can be added to bottom edge of door.
• Radio Control: Universal transmitters and receivers are available to signal the operator to open and/or close.
• Key Switch: Designed to restrict operation of door to authorized personnel only. Various types available.
• Interlock Switch: Prevents accidental operation of the door by interrupting the control circuit.
• Commercial Protector SystemTM (Recommended): An inexpensive "non-contact" photo safety sensor designed to sense an obstruction and signal the door operator to reverse to open.

• Safety of a non-contact infrared reversing sensor
• Fast and easy-to-install
• Patented electrical interface monitors system status at all times
• LED indicators for quick alignment
• One size fits all (for doors up to 30 feet wide)