Apparatus for inspecting electric component for inverter circuit

An apparatus for inspecting an electric component in an inverter circuit composed of a voltage-smoothing electrolytic capacitor, a plurality of transistors, and a plurality of diodes coupled in inverse parallel connection to said transistors, respectively, for protecting the transistors, comprising:

• a DC power supply for supplying a direct current to the inverter circuit;
• voltage detecting means for detecting a voltage at a predetermined position in the inverter circuit;
• current detecting means for detecting a current flowing at a predetermined position in the inverter circuit;
• switching means for changing positions at which the direct current is supplied from said DC power supply to the inverter circuit, positions at which the voltage is detected in the inverter circuit by said voltage detecting means, and positions at which the current is detected in the inverter circuit by said current detecting means;
• switching control means for outputting a switching signal to said switching means;
• electrolytic capacitor determining means for calculating an electrostatic capacitance of the electrolytic capacitor based on a time consumed after the electrolytic capacitor has started being charged by the direct current supplied from said DC power supply through a resistor until a voltage across the electrolytic capacitor as detected by said voltage detecting means reaches a predetermined voltage, and also on a resistance of said resistor, and determining whether the electrostatic capacitance falls within a preset range;
• and
• transistor determining means for determining whether a difference between a collector-to-emitter voltage of each of the transistors as detected by said voltage detecting means when a given collector current is supplied from said DC power supply to the transistor as detected by said current detecting means, and a collector-to-emitter voltage of the transistor as detected by said voltage detecting means when said given collector current is supplied until a junction temperature of the transistor reaches a predetermined temperature, falls within a preset range;
• the arrangement being such that the electrolytic capacitor and the transistors will be determined as to whether they are acceptable or not by changing said positions at which the direct current is supplied from said DC power supply to the inverter circuit, said positions at which the voltage is detected in the inverter circuit by said voltage detecting means, and said positions at which the current is detected in the inverter circuit by said current detecting means, based on the switching signal outputted from said switching control means.