Fatek fbs Plc

[Ali1992 0]

Hello everyone,

I have been using a Fatek Fbs 32 MAC plc to control 3 phase induction motor (380 V, 9A). The PLC's single end relay output goes to an electromagnetic contactor, which basically switches the motor. Recently, one output relay of PLC went defective while there was no damage to the electromagnetic contactor. What might be the cause for failure of output relay?

[ITEC 0]

Check for possible voltage fluctuation or electrical noise upon contactor actuation

[pturmel 159]

Failure of the flyback protection on the contactor coil often proceeds to destroy the contact surfaces in the upstream relay.  But there are many possible reasons for mechanical failures, too.  You would need to dismantle the PLC output to determine anything for sure.