Submittal Sheet

Direct Drive Damper Actuator
M847B
The M847B is a two position, 24 volt spring return damper
operator designed to operate directly driven zone dampers,
used to control air flow in ducts. The motor can be driven open
using any 24 volt rated two position switch - eg. a wall switch or
a thermostat subbase switch.
Specifications
Electrical Rating: 24 Vac 60 Hz 0.32 Amp.
Electrical Connection: 1 metre cable attached.
Nominal Angular Rotation: 90°
Torque: Min. 340 mNm (milli newton meter) [48 in.oz.] output
torque available when motor is energized and device is at the
spring returned position.
Nominal Motor Timing: (@25°C ambient)
Energized at rated load, 24 Vac power source - 30 seconds.
De-energized (spring return) - 20 seconds.
Ambient Temperature Rating: 5 to 60°C (+40 to 140°F)
Finish: zinc plated steel.
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.
Nominal Device Dimensions
LEGEND
1 - Driving Motor 4 - Return Spring
2 - Connection Coupling 5 - Device Case
3 - Anti-rotation Shaft
A B C D
E F G
H
J
K L M
N
mm
60 88 85 56
31.5 13 16
6.4
28
33.5 8.2 45
89
in
2-3/8 3-1/2 3-3/8 2-7/32
1-1/4 1/2 5/8
1/4
1-1/8
1-5/16 21/64 1-49/64
3-1/2
Fig. 1 - Dimensional Details
Installation and Checkout
MOUNTING
WARNING
The M847B can be mounted directly to the protruding damper
shaft using the sleeve attached to the operator output shaft.
1. DO NOT attempt to simulate operation of the operator by
Drill the prescribed hole directly below the damper shaft
rotating the connection coupling, or the damper shaft when it
opening to accept the anti-rotation shaft protruding from the
is connected to the operator.
base of the motor. The length of the damper shaft to which
2. Abuse of this nature can result in stripping the gears in the
drive train of the operator.
04-92 © Honeywell Limited. 1992 • Form Number: 95C-10661-1