<p style="text-align:justify"><span style="font-size:14px">When the circuit breaker opens on fault, there will be an arc struck between two contacts. The arc is quenched but there will be deposition of carbon products on the contacts. Hence, these contacts are to be periodically cleaned after certain ON-OFF functions. Spring adjustment is required to be done after certain breaks. These ON-OFF events and breaks due to fault clearing are recorded by numerical relays and a reminder generated on the front display window to let the maintenance staff know that the maintenance is due. Similar facility for transformer condition monitoring is available in these relays.</span></p>