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Slow-Speed Hoist Operator for Rolling Sheet Doors


Model MHS is an Medium-Duty Logic slow-speed hoist operator for rolling sheet doors. It features a high-starting torque motor with overload protection, adjustable friction clutch, a compact design, and an emergency chain hoist with an electric interlock.

Added Value

  • 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

Motor: Powerful 1/2 HP, 115V single-phase motor with instant reverse, capacitor start and overload protection. Removable without affecting limit switch settings.

Drive Reduction: First-stage heavy-duty 4L V-belt; second and third stages #48 chain.

Emergency Manual Operation: Easy emergency manual operation using a floor level disconnect or an electrically interlocked chain hoist mechanism.
Operator/Motor Control: Solid-state Medium-Duty Logic circuit board.

Control Circuit: 24V NEC Class 2.

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, but requires the presence of either CPS-U, CPS-UN4, or CPS-EI safety devices. The operator is pre-wired to accept a sensing device, photoelectric control, radio controls and most types of access control equipment.

Radio Receiver: 315 MHz radio receiver is integral to the Medium-Duty Logic board. Accepts up to 20 Security+® remote controls and unlimited DIP switch remote controls.

Bushings: Heavy-duty oil-filled bushings.

Friction Clutch: Adjustable, helps protect against major damage to door and operator should the door meet an obstruction.

Construction: NEMA 1 type electrical box, heavy-duty 11-gauge steel frame with durable powdercoat finish, all reduction sprockets drilled and pinned to shafts.

Push Button Station: 3-button station for OPEN/CLOSE functions is standard for all operators. Controls with 1, 2 and 3 buttons are available.

Warranty: 2-year warranty.
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.

Radio Control: Universal remote controls and receivers are available to signal the operator to open, close and stop.

Rolling Door Interlock Switch: Disables the operator control circuit when a manual door lock is engaged, preventing damage to the door and operator.

Wireless Access Control Devices: Weather-proof single- or 3-button wireless control stations are available and compatible with the Medium-Duty Logic on-board receiver. In addition, a choice of either a 5- or 250-code wireless keypad is available. Wireless controls should be used to supplement hard-wired controls and should not be used in place of such controls unless a sensing device, such as photo-eyes or a sensing edge, is present.