Patent ID: 9653906
Date: 2017-05-16
CPC Classifications: F04B,F04C,G01K,H02H

Claim:
1. An overcurrent detection circuit comprising: a current detection device connected between a direct-current power source and an inverter in series therewith, for detecting an electric current flowing through the inverter; an overcurrent level generation device for generating an abnormality judgment reference value; an overcurrent detection device for generating an interruption signal to the inverter on the basis of an output of the current detection device and the abnormality judgment reference value; and an adjusting apparatus for correcting the abnormality judgment reference value of the overcurrent level generation device on the basis of the output at a time when a constant electric current is applied to the current detection device, wherein the overcurrent level generation device includes one or a plurality of resistance value adjusting sections having a fixed resistor and a zener diode connected to the fixed resistor in parallel therewith, and generates the abnormality judgment reference value in correspondence to a resistance value of the resistance value adjusting section, wherein the adjusting apparatus performs a zapping operation by means of applying a reverse-bias to the zener diode, and corrects the abnormality judgment reference value so that the abnormality judgment reference value becomes equal to or less than the output at the time when the current, from which the overcurrent is detected, is applied to the current detection device, and exceeds the output at the time when the current, from which a maximum current in a normal state is detected, is applied to the current detection device, and wherein the overcurrent detection device outputs the interruption signal when the output of the current detection device becomes equal to or more than the abnormality judgment reference value.