MOTOR MULTI-PROTECTION RELAY S91

S91 is a protection device for electric motors that allows the detection of wrong phase sequence or lack of a phase, of the excess current consumption, no-load operation with the power factor measurement. Equipped with rotary programming switches and a display of alarm signaling, the device is characterized by an input for PTC to protect the motor from overtemperature and enable input for starting the engine. S91 operates in 3 operation modes: single-phase or threephase, maximum current range 5 or 16 A, operation with or without PTC. Main applications are protection of single-phase or three-phase pumps for possible rotor stop and for overtemperature as well as device failure detection of mechanical transmission (e.g. belts or chains) with protection against transmission system lockdown.

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Front diagnostics via LED and display.
Simplified settings and adjustments via trimmer and front selector.
Current measurement up to 16 A directly or by Current Transformer.

Maximum rated voltage 660 Vac (F-F).
Motor control input 195 ÷ 255 Vac.
SPDT Relay @ 250 Vac – 8 A.
Alarm, temperature, power factor, maximum current, minimum voltage or phase failure management.