Installation of an Undervoltage Trip Coil in an ABB VD4 Vacuum Circuit Breaker

This video presented by Peter Steciuk of NEPSI shows how to install an undervoltage trip coil (-MU or Undervoltage Shunt Trip or Under Voltage Release Coil) in an ABB Medium-Voltage VD4 circuit breaker. The VD4 Vacuum Circuit Breaker if not ordered properly or if not planned correctly during the design stage can come without an under-voltage trip coil (MU- Option).

For capacitor banks and harmonic filter banks this option is often desired and recommended. It provides protection features that include loss of control voltage (AC or DC), or loss of a relay or control system ready signal, amongst others. In these cases and others, it would be desired to trip the filter/capacitor bank offline as not doing so could leave it unprotected.

If you find yourself in need of an undervoltage trip coil, no worries, as Peter demonstrates in this video, ABB has made is quite simple.