CV Series Single Phase Under Over Voltage Monitor

The CV Series Single Phase Under Over Voltage Monitor from the ATC Diversified Electronics division of Marsh Bellofram combines the voltage monitor with short cycle protectors for appliance control. These units employ a user selectable voltage range Set Point switch.  This switch should be positioned to match the line voltage for proper operation. When the line voltage goes below (brown out) or above the pre-selected operating range, the internal relay drops out removing the plugged-in appliance from these adverse fault conditions. When the voltage returns to the normal operating range, a five (5) minute delay begins. Upon completion, the internal relay picks up allowing the plugged-in appliance to start. LED indicators give an immediate visual reference as to the status of the control. The GREEN LED indicates conditions are normal. When a fault condition occurs the GREEN LED will extinguish and the RED LED will glow. When a fault condition has been corrected, the RED LED will begin to flash. The RED LED will continue to flash until the five (5) minute delay period elapses. At the end of the delay period the RED LED will extinguish and the GREEN LED will glow. When both LED’s are extinguished, a total loss of power is indicated.

The CV-XXX-AFN Series monitors under voltage only and do not feature LED indicators. They also incorporate the five (5) minute short cycle delay. This style is epoxy encapsulated to protect against adverse environmental conditions.



  • Voltage Monitor for Appliances
  • Monitors Over & Under Voltages
  • Built-in Short Cycle Protection with Time Delay Feature
  • 110VAC & 240VAC Models