I fitted a separate filter to VDF 3 phase mill power supply

+1 on the EMC filter. I fitted one when I did my lathe conversion and have never had any issues.
Only thing to watch out for is additional earth leakage, which may trip your RCD.

Is the kitchen radio in close proximity to house wiring, could be that the interference from the inverter is causing a field effect around the house wiring, try moving the radio away from any wiring and see if that makes any difference. My IPhone chargers can cause interference if the wire runs close to a radio, I have an alarm clock/radio on my bedside cabinet and I charge my IPhone on there as well, have to make sure that the charger cable is not near the radio otherwise it causes interference.

Dave W

No one has mentioned or asked the frequencies or bands in use by these radios. Medium wave, VHF/FM, DAB? If they are set to different bands, it is quite likely that one will be interfered with but not the other, even if listening to the same station, Radio Devon in this case.

Depending on your location relative to the fm transmitter your reception could be very variable even at different points around your property (multipath reception). Devon wasn't designed for good fm reception, the terrain is too lumpy (same problem just up the road in W Somerset!). As for MW, I don't have the info to hand but the MW transmitter is probably relatively flea-powered.

Your installation looks good, IMO is a good pedigree piece of kit, I'm not inclined to think there's anything wrong. All VFDs will produce interference, reduced but not eliminated by built in filters. It's quite likely your kit is all 'in spec' but your BBC signals are weak at your location.

Try a different station perhaps.

Radio Devon is on six VHF channels in the area, two MW freq's, DAB Multiplex 10C (Between 174-240 MHz) Freeview Ch. 720, and iPlayer. Mix and match these for best reception on each radio.

It is likely differential mode conducted interference from the VFD causing the issue. You should fit a suitable filter on the inlet. Most VFD instructions say one is required.
The current from differential interference flows in opposite directions on the two conductors.(Live and neutral). Where these are close together and physically balanced the fields cancel and no signal is radiated. This is likely the case near the VFD hence no interference near it. The house wiring on the other hand is less likely to be balanced especially lighting wiring. Un-balanced or separated conductors act as an antenna so when the currents reach the house wiring they radiate and cause interference.

All VFDs should be in a swarf and splash proof (at least IP34, preferably IP 45 or better) earthed metal box with appropriate mains switching, fuse, filter, ventilation or space for cooling and cable glands or connectors.

Robert G8RPI.

I have a old shortwave receiver in the shed, normally on the 20 meter amateur band. I noticed the other day when i powered up the vfd on the mill, it sent the receiver haywire, couldn't hear a thing.