Milnor 72044 WP2, Service, Page: 152 / 202

BMP750047/81307A
MAINTENANCE - VIB SAFETY SWITCH
The vibration safety switch will shut off the machine if properly adjusted. The unit consists of a
sensitive micro switch having a long extended actuating arm on which is mounted on eccentric
weight. The weight may be adjusted both by moving it up and down on the arm, and also by
rotating it on the arm. In addition, the micro switch itself may be turned from side to side.
Upon repeated machine movement caused by out-of-balance, the weight will vibrate sufficiently
to momentarily actuate the switch with electrically causes the 3 wire relay to de-energize.
The unit should be adjusted so that the weighted lever will always reset by itself, this being
accomplished by rotating either the switch or the weight to give just enough bias to cause the
switch to reset. Check the adjustment by moving the arm to the left then slowly releasing it.
Make sure the micro switch “clicks” when arm is slowly released, thus indicating that it has
reset. In the released position, the arm should reset lightly but definitely against the stop on the
micro switch case that prevents any further arm movement to the right.
The sensitivity of the unit increases as the weight is raised on the arm and decreases as the
weight is lowered.
It is not recommended that the adjustment of this switch be changed from the factory setting. It
is, however, true that many installation conditions will dictate readjustment. Essentially, this
device senses the movement of the machine during extraction. In installations with very
substantial foundations and ideal sub-soil condition, very little machine movement will occur for
a given degree of out-of-balance and under such conditions it may be well to adjust the switch to
be very sensitive. In poor installations, or ones where the sub-soil is mushy or springy or
otherwise not as desirable, considerably greater machine movement will occur for a given degree
of out-of-balance, in which case a less sensitive vibration switch adjustment may be indicated.
The vibration safety switch is attached to the frame of the sensing device on the right side of the
machine base of 25 and 60 lb. washer-extractors. Remove the sensing device cover to work on
this switch. On larger machines the vibration safety switch is located in the control box.
NOTE: The vibration safety switch is not installed on machines for shipboard use.