017
2.10 Wiring Notices
◇ Cut o the input power of VFD while dismantling and changing the motor.
◇ Switching of motor or work frequency power supply should only be conducted when the VFD
stops output.
◇ To reduce the eect of EMI (electromagnetic interference), add a surge absorber when
electromagnetic connector and relay are close to VFD.
◇ Do not connect AC input power to output terminal U, V, W of VFD.
◇ Add an isolating device to the external control line or use shield line.
◇ Input order signal line should be wired separately with shielding, and away from major loop
wiring.
◇ When carrier frequency is less than 4kHz, keep the distance between VFD and motor within
50m; when carrier frequency exceeds 4kHz, make an appropriate reduction of the distance,
and better lay the wire in metal tube.
◇ When adding peripherals (lters, reactors, etc.) to the VFD, check the ground resistance with
1000V tramegger and ensure the value is above 4MΩ.
◇ Do not add phase advance capacitor or RC snubber to the U, V, W terminal of VFD.
◇ If the VFD starts frequently, do not cut o the power, use the COM/RUN of control terminal to
conduct start and stop so as not to damage the rectier bridge.
◇ The earth terminal must be grounded reliably (grounding impedance should be under 100Ω)
to avoid accidents, or there might be electric leakage.
◇ Choose the wire diameter according to national electrical code while conducting major loop
wiring.
2.11 Spare Circuit
It may cause big downtime loss or other accidental failure during VFD failure or tripping. Adding
spare circuit is recommended under this circumstance to ensure safety. Note: conrm and test
the operation characteristic of the spare circuit in advance to ensure the working frequency and
the phase sequence of converted frequency are agreed.
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