Delta 1.07 VFD-D D - Manual (Page 119)

Chapter 5 Troubleshooting |DD Series
5-14
5-13 Electromagnetic/Induction Noise
There are many noises surround the AC motor drives and invade it by radiation or power circuit. It may
cause the misoperation of control circuit and even damage the AC motor drive. Of course, that is a
solution to increase the noise tolerance of AC motor drive. But it is not the best one due to the limit.
Therefore, solve it from the outside as following will be the best.
1. Add surge killer on the relay or contact to suppress switching surge between ON/OFF.
2. Shorten the wiring length of the control circuit or serial circuit and separate from the main circuit
wiring.
3. Comply with the wiring regulation for those shielded wire and use isolation amplifier for long
wire.
4. The grounding terminal should comply with the local regulation and ground independently, i.e.
not to have common ground with electric welding machine and power equipment.
5. Connect a noise filter at the input terminal of the AC motor drive to prevent noise from power
circuit.
In a word, three-level solutions for electromagnetic noise are “no product”, “no spread” and “no
receive”.