Patent ID: 7173395

Claim:
An inverter unit grounding method comprising: connecting an inverter unit comprising a sensor circuit to a winding of each phase of a motor and an AC power source; converting the AC power source into DC; switching a switching element on or off to supply current to the winding of each phase of the motor to thereby drivingly control the motor; detecting conditions of the motor with a sensor; connecting a shield braid of a shielded cable to the sensor circuit with an earth plate outside the inverter unit to reduce influence components that are generated as the switching element of the inverter unit is turned on or off; and connecting a 0V of a circuit system to the earth plate, wherein the 0V of the circuit system is connected to the earth plate by the shield braid of the shielded cable, causing impedance for frequency that constitutes the basis of noise upon the circuit system to decrease, thereby lessening influence of the noise upon the system.