Type TR relays are a range of multi-contact attracted armature relays designed to both IEC 255-5 and to BS142. A wide range of models is available to meet the requirements of the electric supply industry. High speed, positive action Can be supplied in modular and drawout type case Robust design for a long, reliable service life TR1 Low burden to ESI 48-4 EB1 & NGTS 3.6.15, ESI 1. TR2 High burden to ESI 48-4 EB2 & NGTS 3.6.15, ESI 2 TR312 NGC (CEGB) P15. (low burden trip relay) TR431 NGC (CEGB) TDM 5/11. (switching relay) TR512 NGC (CEGB) P11 1978. (unstabilising relay) Low burden, TR1 series Type TR1 relays are suitable for application for tripping and auxiliary duties where immunity to capacitance discharge is not required. These relays are not intended for use with current operated series follower relays. High burden, TR2 series High burden relays with immunity to capacitance discharge currents. They are also suitable for certain applications where they are remote from the initiation signal. A high burden also permits reliable operation of current operated series repeat relays. TR relays can be provided with an instantaneous or time-delayed cut-off. Low burden relay, TR312 Designed to meet the requirements of NGC specification P15, this is an electrically reset relay (no flag indicator) with additional terminals in the economy circuit to enable a direct connection to the dc supply. This arrangement allows a reduction in the break duty of the initiating contact. Switching Relay, TR431 Designed to meet the requirements of NGC TDM 5/11, this is an electrically reset relay with a flag indicator which follows the contact operation. These relays are intended to switch protection and auto reclose equipment in and out of service when controlled over pilot wires from a remote point. They are intended to operate from a remote 50V d.c. battery with a pilot loop resistance of up to 200 ohms. Protection unstabilising relay, TR512 Designed to meet the requirements of NGC specification P11, this is a self reset relay without a flag indicator. Special purpose relays, TR9 series This designation identifies TR relays designed to meet a special purpose e.g. TR901 is a high burden repeat relay, a type TR231 with a 2 position flag indicator used as a plant follower relay for circuit breakers and disconnectors. 7PG15 - TR Relays High Speed Tripping D