Multi-protection relays for motors
S91 is a protection device for electric motors. It allows the detection of incorrect phase sequence or phase failure, excess current consumption, no-load operation with power factor measurement. The device has an input for PTC (thermistor with negative temperature coefficient) to protect the motor from over-temperature and enable input for starting the motor. S91 operates in 3 operating modes: single-phase or three-phase measurement, maximum current range 5 or 16 A, operation with or without PTC.
- Protection of single-phase or three-phase pumps for possible rotor blockage and overtemperature
- Detection of breakage of mechanical transmission devices, e.g. belts or chains and to protect against blockage of the transmission system.