Power Open, Power Close Damper Actuator. Replacement Motor For Trol-A-Temp or Trol-A-Temp Dampers. 24-Volt (Ac), 6 Volt Ampere (Va), 50- 60-Cycle, Two-Position Motor Actuator Used with All Aobd, Aobd-Bm, and Iobd Automatic Opposed Blade Dampers. Mstn Is A Uni-Directional Motor That Requires Single-Pole, Double-Throw (Spdt) Switching To Drive The Damper Open and Closed. It Uses A Wafer Switch To Power The Synchronous Motor For Only 30 Seconds While The Motor Is Moving Between Open and Closed or Vice-Versa. When The Motor Reaches The Open or Closed Position, The Internal Switches Cut Off Power To The Motor. Mstn Has Three Auxiliary End Switches, Rated At 1A At 24-Volt (Ac), That Can Be Used To Control Auxiliary Equipment and One Additional Damper When Necessary. Mstn Can Be Operated By Any Trol-A-Temp or Honeywell Zoning Panel. It Also Can Be Operated By Any Spdt Switch or Relay Contact. It Can Be Controlled with Five or Three Wires, Depending On The Application. Replaces Ewc Motor # Man.