6RX31 Trip Circuit Supervision Relay

Features

• Low burden
• Monitors CB in both open & closed condition
• Contacts picked up for healthy supply condition contacts
• Slug time delay
• Hand reset flag indicator
• 2 C/O contacts standard
• Draw out case
• Equivalent function to MVAX31
• 1TM12 specification

Application

The operating element for the 6R MATRIX supervision relay functional elements are designated 6RX & are based on our 6R Series relays.

The operating element of the 6RX31 comprises three 6R heavy duty attracted armature relays as shown below. Supervision is active with the circuit breaker in the open or closed position via the “a & b” CB auxiliary contacts.

Under healthy conditions, with the CB in the closed position, relay 1 & 2 are energized & if the trip coil becomes open circuited or the supply fails, relay 2 will drop out causing alarm relay 1 to drop out & initiate the local visual indicator & output contacts. Similarly, when the CB is in the open position, relays 1, 2 & 3 are energized enabling the relay to detect failure of the trip circuit coil or supply in the same manner as if closed. Once set the alarm relay flag must be hand reset. If the protection trip contact operates alarm relay 1 will drop out after 300ms (approx.) unless the CB auxiliary contact opens within this time causing relay 3 to pick up. The 300ms delay prevents false alarms due to normal delays in the tripping operation."

Relay 1 element is fitted with a slug to provide a delay of 100ms (approx.) on deenergization to prevent false alarms due to voltage dips in the supply rail. If the protection trip contact should fail to reset, due to a failure of the circuit breaker tripping mechanism for example, the relay drops out initiating the local visual alarm indicator & output contacts