The BD 5936 detecting standstills of 3- and 1-phase asynchronous motors. At 2 terminals of the stator winding the BD 5936 measures the voltage of the slowing motor which has been induced. If the induction voltage approaches 0 this indicates that the device is at a standstill and the output relay is activated. Additional the monitor detects strand breaks between measurement inputs Z1 / Z2. If a line breakage is detected, the output relay goes into the normal position (as when the motor is running). This state is saved and can only be cleared by (briefly) switching off the auxiliary voltage.