Liftmaster Medium Duty Trolley Operator

Model: Liftmaster - MT
Drive Type: Chain Drive
Horse Power: 1/2 Horse Power
Warranty: 2 Year Warranty

Model MT is a Medium-Duty Logic trolley operator for standard lift sectional doors. It features a high-starting torque motor, a compact design, quick-gliding rail spacers and a quick-mount swivel header bracket.

Medium-Duty Logic Technology


  • UL325-2010 compliant Medium-Duty Logic programmable integrated circuit board

  • Built-in 3-channel, 315MHz radio receiver accepts up to 20 Chamberlain® Security+® or unlimited DIP switch remotes.

    3-button remotes can be programmed for OPEN/CLOSE/STOP operation

  • Programmable C2 or B2 wiring options (B2 requires CPS-U, CPS-UN4, or CPS-EI)

  • Integrated Timer-to-Close (TTC) allows programming from 5 to 60 seconds in 5-second increments. Allows for timed automatic door closure after the door reaches the full open position (Requires monitored safety devices, with CPS-U, CPS-UN4, or CPS-EI)

  • Integrated 90-second maximum run timer

  • UL325-2010 Monitored Entrapment Capability

  • Monitored protection against transient overvoltage conditions

  • 3-button control station included

Standard Features


  • 2" thick sections constructed of pre-finished galvanized steel

  • Insulated models feature either heavy duty vinyl or 27 gauge steel backers

  • The steel characteristics and thickness used in models 3250/3251/3252 are equivalent to the "nominal 24 gauge" classification used by other manufacturers in the door industry

  • Box shaped stiles are riveted to the face of the section and are galvanized for additional corrosion protection

  • Tongue and groove meeting rails provide superior rail strength and weather resistance

  • Glass is available in 1/8" DSB, 1/8" Lexan, Insulated or 1/4" tempered glass

  • Glass is easily replaced or substituted by removing molded frames

  • Exhaust port is optional for bottom section

  • Track options include 2" or 3" bracket or clip angle mount and designed to accommodate virtually any headroom design requirements

  • Heavy duty hardware may be specified with 11 or 14 gauge hinges and 10 ball rollers

  • Bottom U-shaped astragal in an aluminum retainer is standard

  • Increased windload requirements may be specified

  • All models are available in finishing coat of white. Additional sandstone, brown and gray finishes are available in models 3240/41/42 ONLY

Control Accessories and Options

Primary Monitored Entrapment Protection: The presence of primary entrapment protection is required for all modes and features beyond basic constant-pressure-to-close performance. Primary entrapment protection devices are monitored continuously to insure safe operation of the door and limit door operator functionality should an obstruction be detected or in the event of device failure. LiftMaster Monitored Entrapment Protection devices, CPS-U, CPS-UN4 and CPS-EI, are designed to work in conjunction with LiftMaster commercial door operators to provide enhanced door safety and a broad range of modes and features to end users. Either monitored photo-sensor or monitored 4-wire sensing edge (in conjunction with the CPS-EI Edge Interface) protection may be selected, but one must be detected by the LiftMaster Logic 4.0 or Medium-Duty Logic circuit board in order to unlock full functionality.


Ancillary Entrapment Protection: (optional) LiftMaster Retro-Reflective Commercial Protector System® photo sensors, 2-wire non-monitored sensing edges and pneumatic sensing edges are considered secondary entrapment protection and may be used to supplement primary entrapment protction or basic constant-pressure-to-close.


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.


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.