6RX21 Trip Circuit Supervision Relay

Features

• Low burden
• Monitors CB in both open &n 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 MVAX21
• 1TM10 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 6RX21 comprises a single 6R heavy duty attracted armature control relay with two operating coils wound on a single core.

Supervision is active with the circuit breaker in the open or closed position via the 52a & b auxiliary contacts.

Under healthy conditions, with the CB in the closed position, coil winding 1 is energized & if the trip coil becomes open circuited or the supply fails, the relay will drop out initiating the local visual indicator & output contacts. Similarly, when the CB is in the open position, both coil windings are energized enabling the relay to detect failure of the trip circuit coil or supply in the same manner as if closed. Once operated the electro-mechanical alarm flag must be hand reset.

The relay element is fitted with a slug to provide a delay on de-energisation preventing a false alarm due to voltage dips in the supply rail, or the normal delays in the tripping operation, when the first coil winding is momentarily short circuited by the protection trip contact. 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.