Product description

Phase failure relay (sequence and phase failure) for protection of three-phase motors. Action against phase breaks, or inverted sequence of motor phases.

Applications

• Protection of three-phase motors against phase breaks or wrong phase sequence
• Protection against phase unbalance
• Control of the voltage value in generator sets

Operation

Power the relay (green led on – A.1)

The “S1” contact arms when the phase rotation is in sequence and the voltage value of all three exceeds the set minimum limit on the front panel scale, whether or not the neutral is present.

The “S1” contact disarms when the individual value of the measurement of one or more phases falls below the set minimum limit.

The neutral connection is optional, however when connected improves the stability of the measurement.