Inverse time relay ICM 21

The relay type ICM is an over current relay with an inverse-time characteristic. That means to say, its tripping time is shorter, the greater the fault current. As secondary relay parts it is fed by current transformers. It is used to protect parts of electrical installations and simple line systems against over current, earth fault and short circuits. For the protection of solidly earthed systems against earth faults, relays are available with current setting up to 0.1 A. The relay can be employed in all situations where delayed interruption of short circuits is required, provision also being made for instantaneous tripping at a set maximum current.