220 volt huanyang vfd

[Aiph5u (Aiph5u (not affiliated with Onefinity))]

Hey Dean,

@Dustoff00

From what I understand, the shielding/drain wire should only be tied to the Earth ground on the side of the vfd. Otherwise you could have a ground loop. (i.e. a shielding/drain wire should only be grounded on one end.

Since the 4th wire, PE, is already there, and shield and PE are interconnected, there can not be a ground loop introduced by connecting shield at both ends. If there was a ground loop, it would already be there with the PE wire.

Also PE and shield do not participate in a current flow here (=PE and shield are no circuit conductors that complete the circuit back to the source). The three-phase current here needs no neutral wire. PE is just for safety here.

Both earth portions of the shielded cable must be connected to the earth point by cable clamps.

– Source: Omron MX2 User’s Manual

An example of a ground loop is if your cable TV provider grounds its cable in his distributor board out there a few miles down the road and then it is grounded again at your cable TV wall outlet or in the receiver. This can produce a lot of hum that deteriorates the signal. This is because in an unbalanced line, ground participates in signal flow (=ground is a circuit conductor that completes the circuit back to the source here). The solution here would be galvanic isolation.

@Dustoff00

You will also need to check for continuity on pin 4 on the spindle to the casing of the spindle. If there is no continuity, you will need to ground the chassis to the inside of the Pin4 connector. Some of the spindles, this is done at the manufacture, but many it is not done as this is not a requirement in China.

You are right here, internal connection between the 4th pin (PE) and the spindle case, and then the PE wire connected to earth, is mandatory in terms of saftey. For the same reason, all metal parts of a CNC machine should be grounded too.