Rpm Sensor (Hall Effect) Adjustment - Chamberlain LiftMaster Professional SW420 Owner's Manual

RPM SENSOR (HALL EFFECT) ADJUSTMENT

NOTE: Normally the RPM sensor (hall effect) does not need
adjustment, but may go out of alignment due to shipping
vibration or rough handling.
These operators use an internal entrapment protector system.
This system consists of the control board, magnet, and RPM
sensor. It may become necessary to adjust the sensor for correct
alignment. To do so please perform the following steps:
1. Loosen the two screws holding the hall bracket to the frame.
2. Adjust the bracket so that the sensor is:
a. Parallel with the pulley.
b. .020" (.051 cm) away from the pulley's magnet. Use a
feeler gauge to measure the distance.
3. Tighten screws to secure assembly.
4. Manually rotate pulley to ensure that each magnet clears the
sensor board.
If a magnet does not clear the board, re-adjust the RPM
(hall effect) assembly accordingly.
Cable
A D J U S T M E N T
Mounting
Operator Chassis
Screws (2)
To reduce the risk of SEVERE INJURY or DEATH:
CAUTION
• Disconnect power BEFORE performing ANY adjustments.
Bracket
ADVERTENCIA
PRECAUCIÓN
18
WARNING WARNING
Pulley
Pulley
Magnet
AVERT
AVERT
ATTEN
AVER