Application

The protective stator earth fault relay type RMC-142D forms part of a complete

DEIF series of relays for protection and control of generators. The RMC-142D

is primarily designed for land-based installations. Also available are short circuit

relays (RMC-111D), combined short circuit and over-current relays (RMC-122D)

and double over-current relays (RMC-132D).

The RMC-142D is CE-marked and is applied for protection of voltage sources and

load networks against earth fault in a solid earthing or a low-resistance earthing system.

Normally de-energised contact

Recommended for installations for regulating and control purposes.

An auxiliary supply failure will not result in an unwanted activation of the contact.

Latch circuit

The contact can be locked in its warning position, even if the earth faulty current

(leakage current) returns to normal (add “L” to contact type in order specifications,

if this is required). The latch circuit is reset by disconnecting the auxiliary supply.

Hysteresis

In order to avoid “chatter” on the relay contacts the contact functions are provided

with a hysteresis, that is a difference of 2 % of full scale between energising and

de-energising of the delay.

Power-up/power-down circuits

The RMC-142D is provided with a 200 ms power-up circuit, ensuring the correct function

of the relay on connection of the auxiliary voltage.