The RSH-3 relay is a very fast (t ≤ 3ms) interposing relay intended mainly for controlling the power breaker coil. The relay has a high switching capacity and therefore it can frequently interrupt current in the power breaker coil operating in a 220V DC circuit. For instance number of operations for current of 3,2 A exceeds 5 000 times, and for current of 1,2 A exceeds 25 000 times. The RSH-3 relay is suitable to control typical power breakers used in 110 ÷ 400 kV substations.