Interposing and supervision relays
The range comprises electro-mechanical relays for a range of auxiliary and tripping functions. Various combinations of coils, contacts, operation indicator flags can be specified. Options are also available for operate and reset modes. 7PG17 XR relays - Interposing relay for control applications, supply supervision, trip circuit supervision, ferroresonance alarm.
- Interposing Relays:
The interposing relays are intended for the remote control operation of switchgear over pilot wires with a maximum resistance of 200 ohms. The relays are designed so that they are not susceptible to certain a.c. voltage levels which may be induced onto the pilot wires.
- Supply Supervision Relays:
The supervision relays are designed to monitor DC Voltages. They have a low operating current, specific settings, time delayed drop-off, a mechanical flag indicator which shows on de-energisation and contacts for the ability to initiate remote alarms.
- Trip Circuit Supervision Relays:
These relays are for the monitoring of the circuit breakers trip circuit to ensure integrity at all times. There are differing preferences for monitoring a trip circuit and our range is designed to meet these requirements.
- 7PG173 – Interposing Relays
Type XR205 and XR206 are two element versions of the XR105 and XR106 respectively with the same performance. Type XR105 has no flag indicator, XR106 and XR107 have a hand reset flag. Both types are available with a suppression diode across the coil to reduce the effects of the back emf which occurs on switch-off.
- 7PG1751 – Trip Relay Supervision
Type XR151 relays are designed to allow the supervision of a trip relay operating coil, supply and associated wiring.
- 7PG174 – DC Supply Supervision Relay
Types XR152 and XR153 relays are designed to comply with CEGB and other specification for protection supervision requirements and the monitoring of d.c. voltage supplies. These applications require relays with low operating current, visual indication and the ability to initiate a remote alarm.
- 7PG175 - Trip Circuit Supervision
XR250 and XR251 circuit breaker closed supervision will initiate an alarm and provide indication with the circuit closed for: Failure of the trip supply, open circuit trip coil, an open circuit in the trip circuit wiring and if the trip coil should fail to respond to a trip command.
- XR350 and XR351 provide continuous supervision with the circuit breaker in the open and closed positions and in compliance with the scheme requirements of BEBS S15 scheme H7. XR350 and XR351 relays also have a contact for pre-closing supervision, where a circuit breaker is prevented from being closed if trip relays have not been reset. BEBS S15 scheme H7 is applicable to trip circuit voltages of DC 125 V and DC 240 V.