2-3 Wiring Countermeasures Against Induction Noise To reduce induction noise from the output side, the following method is also effective. •Run the cables collectively through the mounted metal pipe. Keeping the metal pipe at least 30 cm away from the signal line reduces induction noise. Molded case circuit-breaker (MCCB) Power supply 2 Inverter 3G3MX M Design 30 cm min. Signal line Controller Cable Length Between Inverter and Motor Use a cable of 50 m or less between the Inverter and the motor. If the cable length is increased, the stray capacitance between the Inverter outputs and the ground is increased proportionally.
An increase in stray capacitance causes high-frequency leakage current to increase, affecting the current detector in the Inverter's output unit and peripheral devices. If your system configuration requires a cable length of 50 m or more, perform the following: •Wire in metallic ducts. •Use separate cables for each phase. •Set the Inverter to a lower carrier frequency (b083). Do Not Use Single-phase Motors •A single-phase motor uses the capacitor start method or split-phase start method to determine its rotation direction at startup, and thus is not suitable for the variable speed control via the Inverter. Do not use single-phase motors.
*If a capacitor start motor is used, the capacitor may be damaged by a sudden electric charge and discharge caused by Inverter output. If a split-phase start motor is used, the startup coil may burn because the centrifugal switch does not operate. 2-22