MST Motor Switch Terminal

click to zoom
(2 more images)

In Stock

Trol-A-Temp MST Motor Switch Terminal

The Motor Switch Terminal, Model MST, is a 24 Volt, AC two-position motor. This motor is used with Trol-A-Temp and EWC opposed blade dampers, automatic registers and diffusers. The MST replaces the similar Trol-A-Temp model and the EWC MAN model.  Can replace part # MSTN.

The MST requires a Single Pole-Double Throw (SPDT) to operate the motor to the open and closed position. Once the motor reaches the Open or Closed position, the motor's internal end switches cuts power to the motor. Therefore the MST only uses power while moving between open and closed. Once the motor is in either the open or closed position it consumes no power. The MST also has 3 auxiliary end switches that can be used to turn on the furnace, fan or cooling when the damper is open, as well as control a secondary slave damper. See the legend below for the function of each terminal.

NOTE :  This Trol-A-Temp MST is shipped in the "OPEN" position

Terminal Functions

24 Volt Power Common -C
(2) 24 Volt Power Hot -R
(3) End Switch, makes to 2 when damper is 50% open and breaks when 50% closed. Typically used to turn furnace on for Heating Only.
(4) Makes with 5 to drive motor OPEN.
(5) Common of switch and makes to either 4 or 6 to operate damper.
(6) Makes with 5 to drive damper CLOSED.
(X) End switch that makes with 2 when damper is closed. Typically used to control slave damper.
(Z) End switch that makes with 2 when damper opens.
Typically used to control a slave damper.