Inverter interference

it’s not industrial equipment, it’s a small wood turning lathe offered to home users.

Thanks to everyone else for your comments. There seem to be several possible solutions but at least one may require the services of someone more experienced with electrics. Possibly the simplest solution would be to use this with the camera?

**LINK**

or maybe this.

**LINK**

Any thoughts on them?

We all seem to have assumed the inverter is emitting unacceptable levels of EMC. It is quite possible you have a camera (and maybe my digi readout transformer as well) that has substandard protection from mains borne EMC.

Martin

Totally missed the point. I was trying to explain why VFDs do not generally have built-in filters. The manufacturers don't give two hoots about home users, but design for the requirements of industrial installations.

I apologise for mentioning engineering on a modelling forum.

Andrew

I had to earth both ends of the screened cable before the interference stopped on my set up.

Just becuase the issue has only shown up with the video camera does not allow you to determine if the camera has poor immunity or the lathe hs excessive emissions. It could be either, or a bit of both.
As Andrew has already said the VFD unit is a component intended for industrial applications Thus it is designed to industrial emissions regulation maximum levels which are higher than domestic. Assuming the camera is a domestic unit it legally only needs to be immune (perform to a level defined by the manufacturer) to the lower domestic levels of interference.

It is actually quite difficult to get most VFD emissions down to the domestic levels. I've done it on various equipment. An example was bench mounted machine with three small drives and had to run from a "13A" socke in a lab envvironment. It required additional filters on the input of each drive, reactors (inductors) on the outputs, putting the drives inside a screened box (in addition to the basic metallic enclosure of the machine) and screened cables.
To reduce leakage current from the filters and screened cables an isolation transformer was required (This had some tricks in it's specification that helped with other issues). Adding the isolation transformer then required extra attention to electric shock protection.......

That level of effort is OK for a professonal machine costing 5 to 6 figures. People selling 3 to 4 figure hobby tools tend not to bother so much.

Vic, If you are anywhere near Cambridge (UK) I could come round and make some measurements.

Robert G8RPI.

.

My thoughts: They would help reduce the effects of mains-borne interference … BUT would be of little help if the interference is ‘airborne’

MichaelG.

.

See Andrew’s first reply, on p_1

Edited By Michael Gilligan on 23/02/2022 22:43:32

Thanks folks. Thanks Robert but I’m in Dorset and I don’t have free access to the equipment anyway. I can only go on the information I’ve been given. As I said in the OP I’ve been informed it’s mains not airborne interference. I think I’ll pass on the links to the two items mentioned and let them make a decision. If it’s solved I’ll come back with the solution in case it’s of help to anyone else.