Stand Alone Bac Heater Control Panels; Vibration Cutout Switch (Vcos) - BAC FXV-0806-12D Series Operation & Maintenance Manual

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.
Figure 9. Electronic VCOS with Alarm Contact is Shown
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Vibration Cutout Switch (VCOS)
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.
Electronic Vibration Cutout Switch (Optional)
Two models of electronic vibration cutout switches are available. The single set point model
contains one trip limit for shutdown. The dual set point model contains two independent trip
limits; one for alarm and one for shutdown. The shutdown set-point is factory set at
0.45 in/sec. Additional details can be found in the submittal packet.
Warning: Before performing an adjustment or inspection of the VCOS, make certain that all power
has been disconnected and locked in the off position. Moisture inside the switch can lead to
switch failure. Care must be taken when replacing the cover on the vibration switch to ensure
that the proper watertight seal is obtained.
Testing:
• The test position sets in the minimum set point so that any vibration will cause a trip condition.
• The light will come on immediately, and the trip will occur after the duration of the time
delay, proving the complete system is operational.
• If test position is maintained for less than the duration of the time delay, the trip will not
occur, thus permitting the system test without shutdown.
Calibration:
• A light adjacent to the set point control comes on the instant the
measured vibration level exceeds the set point.
• The unit can be periodically calibrated on line by turning the
set point control down until the light comes on. This setting is then
compared with the vibration measured with a portable vibration meter,
thus providing a calibration check of the unit.
• If the trip setting is maintained, trip will occur after the duration of
the time delay.
Remote Reset: Connection of between terminals 6 and 7 latches electromechanical relay output in
alarm state after set point is exceeded. Opening the connection will reset the output to non-alarm state.