Direct Drive Damper Actuator
The M847D is a two position, 24 Vac spring return damper
actuator designed to operate directly driven zone dampers,
used to control air flow in ducts. The synchronous motor
actuator can be driven open (or closed) using any 24 volt
rated two position switch - e.g. a wall switch or a thermostat
The M847D replaces the RDMH and RDMZ damper actuators
for use on Trol-A-Temp® ARD and ZD dampers.
Electrical Rating: 24 Vac 60 Hz 0.32 Amp., 8 VA
Electrical Connection: 1/2" conduit
Nominal Angular Rotation: 90° (max. 105°)
Torque: Min. 423 mNm* (60 in. oz) output torque available
when motor is energized and device is at the spring
returned initial start position.
Nominal Motor Timing: ( @ 25° C ambient)
Energized at rated load - 30 seconds.
De-energized (spring return) - 10 seconds.
Ambient Temperature Rating: 5 to 60° C (+40 to 140° F)
Finish: zinc plated steel, anodized aluminium
Direction of Shaft Rotation: clockwise, when energized and
viewed from the base or shaft end.
Mounting Means: direct connection to damper shaft.
Mounting Position: Multi-poise.
Dimensions: See Figure 1.
*mNm = milli newton meter.
Table 1. Nominal Device Dimension
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