Patent ID: 7737645

Claim:
An electronic trip unit for a motor circuit breaker of an electric motor, comprising: at least one detection unit configured to sense at least one current that is delivered to the electric motor so as to provide at least one corresponding measured current value; a discriminator circuit, the discriminator circuit being in a first state when no measured current value of the at least one measured current value exceeds a predefined trip threshold, the discriminator circuit being in a second state when at least one measured current value of the at least one measured current value exceeds the predefined trip threshold, the discriminator circuit including: an output configured to output a control signal for controlling the motor; a voltage-limiting component having a breakdown voltage, the predefined trip threshold being determined by the breakdown voltage; a resistor connected in series with the voltage-limiting component; and a switching unit configured to, in the first state, switch the control signal to the first level, and, in the second state, switch the control signal to the second level, the switching unit being configured to be switched by a voltage drop across the resistor.