Vibration Cutout Switch (Vcos); Mechanical Vibration Cutout Switch (Optional) - BAC Vertex VRC A-1012N Series Operation & Maintenance Manual

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. Both are located on the outside of the unit, next to the access door. For units
equipped with the EC fan drive system, vibrations are monitored by built-in sensors in the motors. A separate vibration cutout
switch is not needed.
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.

Mechanical Vibration Cutout Switch (Optional)

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 fans 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.
Vertex™ Evaporative Condenser Operation & Maintenance Manual – Operation Considerations for Accessories
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