Member postings for Paul Thomas 1

Update.

I was able to get my hands on another VFD unit to check the value of the resistor. It turns out it is a 390 ohm.

I checked the relay by removing it from the circuit and checking it. It's fine. The capacitors aren't shorted at least.

I put it all back together, but still no joy. I suspect the mosfets may also be blown, so next step is to remove them and check.

I'll come back and give an update when I've done that.

Thanks again.

You guys are the best !

Thanks very much for your help. I'll go ahead and find a resistor and try it out. I'll come back with feedback once I've done that.

Best wishes for the new year.

Paul

Still trying to load the first picture.....in the meantime, here's the link to the Album entry

https://www.model-engineer.co.uk/albums/member_photo.asp?a=58742&p=917745

Thanks for your answers.

Sorry for the second photo. It is in the Album named "VFD", but looks like it didn't insert into the post. I'll try to get that in a follow-on post below.

The green component reads OL on the multimeter, so open circuit. There are no other components that appear to be damaged.

Any idea of what nominal value would be suitable for the resistor? I may have some old PCBs lying around that have some resistors I could recycle, otherwise it'll be a trip to the local electronics store.

Paul

Hi all,

I have an inverter to convert 220VAC monophase to 380VAC triphase (XSY-220T380-RY is the marking on one of the PCBs inside the box, bought as XSY AT4). It worked fine on my Schaublin 102 lathe, but when I tried running a newly acquired Schaublin 12 milling machine, something started burning in the inverter. (I later discovered that the milling machine only had 2 phases out of 3 connected through the power-on switch, so I suspect the imbalance may have caused some problems....but that's a problem for another day.....back to the inverter...).

I opened it up, and the burned component is one of 2 components on the breakout board in the bottom left of the photo. I am trying to identify it to replace it, but there are no markings. I am hoping that someone can point me in the right direction as to what it is. It is mounted beside a power relay, JQX-105F-1 024D-1HS, which is a 24VDC coil, 250VAC 30A output, form A, sealed unit that seems to still be functional. As there is normally a flyback diode mounted directly beside a relay in DC applications, I suppose that the burned-out component is a diode. However, it's not a form that I recognise. As I said, it has no markings, it is green, axial, has a fairly heavy feel to it, has some kind of matt-ish friable coating over what appears to be a metal casing.

Does anyone recognise it? If indeed it is a diode, what is the type and probable ratings so that I can find a suitable replacement?

Is it possible that the relay itself is used as some kind of AC relay, and the green component is some other kind of current limiting device, like a thermistor or something?

The first photo shows the green axial component removed from the burned board, bottom right, and placed on top of the large capacitor for the photo.

The second photo is one I copied from a posting on this site showing the component in place on a functioning board.

Thanks in advance.