[Newbie] VFD Undervolt Error with SVC

[slow-poke]

IF those are the generic (read cheap Aliexpress type resistors), your asking for a catastrophic VFD failure. Good quality resistors from reputable manufacturers have a isolation voltage rating often in the 500V - 2kV range. I Hi-pot tested a bunch of those cheap ass resistors and many failed at low voltage, some with very low voltage. Zero chance I would connect Ali type power resistors to 380V.

With power off and fully discharged, I would unscrew and isolate those resistors from the heatsink and see what happens. Their not going to overheat for the testing you're doing. If that happens to solve the problem order a quality name brand resistor like Dale, Ohmite.

 

[mMcFab]

IF those are the generic (read cheap Aliexpress type resistors), your asking for a catastrophic VFD failure. Good quality resistors from reputable manufacturers have a isolation voltage rating often in the 500V - 2kV range. I Hi-pot tested a bunch of those cheap ass resistors and many failed at low voltage, some with very low voltage. Zero chance I would connect Ali type power resistors to 380V.

With power off and fully discharged, I would unscrew and isolate those resistors from the heatsink and see what happens. Their not going to overheat for the testing you're doing. If that happens to solve the problem order a quality name brand resistor like Dale, Ohmite.

Noted, I'll get something better ordered if I can get past the current issues first (disconnecting the brake load has no effect on the running, general consensus is I'm causing too much voltage sag (probably with tiny baby wires, maybe the house just can't take it), will be able to confirm this for sure tomorrow after I replace all the wiring + input cable and plug in closer to the breaker), I'm of the opinion that there's not much point me replacing that stage before the motor can successfully start up tho (the only reason I added an external brake load in the first place was to see if that would fix anything, but yeah. ended up not changing anything)

 

[mMcFab]

Ok! It's solved. I received my thicker wires today, hooked em up and plugged the thing in to the closest plug to the main breaker and...
It works! That was it, I now get a maximum voltage sag of half a volt with the mains sitting at 220V today. I think a 0.23% drop is considerably better than the 17.4% I was getting the other day, and definitely code-compliant on that front now. Oh and of course the motor actually starts up consistently now. Yay! Now I just gotta hope it can keep it up when it's actually under load.
So I need to rearrange some things to minimise the VFD->mains distance for sure, and I'm also gonna update the wiring inside the box (update the brake load too, and probably add a voltmeter to the box so I can keep an eye on things and e-stop if something goes awry)

Seriously, huge thank you everyone!