Wiring Main Circuit Terminals2- 19Countermeasures Against Radio InterferenceRadio noise is generated from the Inverter as well as from the input and output lines. To reduce radio noise,install noise filters on both input and output sides, and also install the Inverter in a totally enclosed steel box.The cable between the Inverter and the motor should be as short as possible.Fig 2.11 Countermeasures Against Radio InterferenceCable Length between Inverter and MotorIf the cable between the Inverter and the motor is long, the high-frequency leakage current will increase, caus-ing the Inverter output current to increase as well. This may affect peripheral devices. To prevent this, adjustthe carrier frequency (set in C6-01, C6-02) as shown in Table 2.6. (For details, refer to Chapter 5 User Con-stants.)Ground WiringObserve the following precautions when wiring the ground line.• Always use the ground terminal of the 200 V Inverter with a ground resistance of less than 100 Ω and thatof the 400 V Inverter with a ground resistance of less than 10 Ω.• Do not share the ground wire with other devices, such as welding machines or power tools.• Always minimize the length of the ground wire.Leakage current flows through the Inverter. Therefore, if the distance between the ground electrode and theground terminal is too long, potential on the ground terminal of the Inverter will become unstable.• When using more than one Inverter, be careful not to loop the ground wire.Fig 2.12 Ground WiringTable 2.6 Cable Length between Inverter and MotorCable length 50 m max. 100 m max. More than 100 mCarrier frequency 15 kHz max. 10 kHz max. 5 kHz max.IMInverterMCCBPowersupply Metal pipeNoisefilterNoisefilterSteel boxOK NO
