Mechanical Vibration Cutout Switch; Electronic Vibration Cutout Switch - BAC HXV Operation & Maintenance Manual

Mechanical Vibration Cutout Switch

The Mechanical Vibration Cutout Switch and the Optional Electronic Vibration Cutout Switch
should be tested and field adjusted at start-up and yearly thereafter.
Mechanical Vibration Cutout Switch (Standard)
Set Point Adjustment When Installed:
1. For safety, turn off, then lock and tag-out the electrical supply to the fan motor(s).
2. Turn adjustment screw counterclockwise 1/8 turn at a time until you hear the control trip.
3. Once tripped, rotate adjustment screw ¼ turn clockwise. Push in the manual reset button.
4. Start up the fan(s) to determine if the start-up will cause the cut-out switch to trip.
5. If the VCOS does not trip, start and stop the fan two more times. If the VCOS still does
not trip, then calibration is complete.
6. If the VCOS trips, follow the steps in the note to the right.
Electrical Reset and Start-up Lockout (Optional):
1. If rated voltage is continuously applied to the reset circuit at unit start-up, the reset solenoid
energizes for a fixed time interval (approximately 30 sec), after which time the solenoid is
automatically de-energized by the thermistor. This provides a trip lockout during machine
start-up roughness.
2. The voltage must be removed from the reset circuit when the machine is stopped to allow
the thermistor to cool off.
3. The switch mechanism can be reset electrically by a momentary application of the reset
voltage or it can be reset manually.
Electrionic Vibration Cutout Switch (Optional)
The single set point, electronic hybrid vibration cutout switch (VCOS) contains one trip limit
for shutdown. The shutdown set-point is factory set at 0.45 in/sec. Additional details can be
found in the submittal packet.
Operation
Considerations for
Accessories
Stand Alone BAC Heater
Control Panel
Operation
Vibration Cutout Switch (VCOS)
Mechanical Vibration Cutout Switch

Electronic Vibration Cutout Switch

NOTE: If the VCOS trips, turn off,
then lock and tag out the electrical
supply to the fan motor(s). Adjust
the set point screw an additional
1/4 turn clockwise, and push in the
manual reset button. Start up the
fan motor(s) to determine if the
start-up will cause the VCOS to trip.
Repeat this adjustment process
until the VCOS no longer trips when
the unit is operated. Make sure to
lock out and tag out the electrical
supply to the fan motor(s) before
entering the unit or re-setting the
switch, each time an adjustment
to the VCOS is made. After the final
adjustment has been made, start
and stop the fan motor(s) two more
times to ensure that the VCOS is
properly set.
Calibrated set point controls enable
operator to set specific velocity points.
Figure 12. Electronic VCOS with Alarm Contact
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