VFD error

[routercnc]

I was cutting this morning and all of a sudden there was a large blue flash from the connector into the top of the spindle, and the RCD tripped on the consumer unit.

The connector is the standard 3 pin type for chinese wc spindles. Looking inside the female part of the connector (from the VFD) showed a burn mark around the clear plastic sleeve. I checked the resistance between each socket and earth, checked the spindle pins for resistance (about 2.2ohms so ok there) and resistance to earth. All fine.

I then noticed that the pins which stick up inside the spindle connector are split down the middle to provide some spring loading and make good connection. 2 of them had a gap between, but the third one was fairly close together. This meant that when the connector was applied, the pin wasn't making a great contact.

I think this was enough to momentarily break the circuit to the spindle (while it was cutting!). Part of the reason for this is probably because (like many DIY machines I suspect) the cable from the VFD goes into the spindle and any movement of the machine during cutting continually strains the cable. I've been running like this for about 4 years, and kept meaning to make a strain relief arm, but never have done.

Knocked one up in about 30 minutes after the problem, but it's too late now.

Now I can't start the VFD. It keeps telling me there is a fault (E14 - UVW to earth fault). It does this without the spindle connected, plus without the VFD cable connected. There is a reset procedure which involves briefly connecting a terminal mark P24 (24v?) to pin 5, which make symbols on the display goes round in little circles. But the error remains.

I've tried switching on and off many times, held the reset for a long time, nothing. Wondering about if there is a factory reset option. Also wondering if I've damage the VFD. It is a Moeller DV51.

Any ideas?

Thanks

p.s. Start making up strain relief arms for your spindle cable - you have been warned!

[IanParkin]

Cant help you with the inverter other than read the manual for any ideas but as to the the plug on the top of the spindle I removed the end cap and removed the socket and then drilled for a cable gland and hard wired the wires in with a good earth connection with 1.5mm2 cable to the inverter ..
The plug and socket doesn't look good to be carrying 5-8 amps at 240v
Ian

[IanParkin]

Have you done whats mentioned on page 65 of the manual?
Have you rewired from inverter to spindle?

[routercnc]

Hi Ian,

Yes, I didn't like the look of the connector from day 1 but it has worked ok up until now. If I had bothered to make the strain relief arm I think it probably would have lasted.

On page 65 of the manual I'm looking at it just talks about setting parameters:
"You can adapt the DF51 to your specific applications. To do this,
you need to change the frequency inverter’s parameters with the
built-in keypad, the optional keypads DEX-KEY-…"

Did you mean this or is there another manual you are looking at?

Also, to be clear, the spindle is not connected to the VFD, and the cable to the spindle is completely removed, so wiring the spindle direct won't help at this point. The VFD won't get past the error code on startup. I wonder if something is damaged inside.

I've managed to find all the settings for the VFD which I made 4 years ago, so if I can get it to work with after a reset I can get it going again quite quickly. Just can't find out how to do it . . .

[longy]

Does your spindle have the GX16-3 connector ? Have a look at the PLUG as well and see if there are any burn marks on the female pins they are split as well. I t could be the cable from the VFD has a break somewhere and that has shorted back to the spindle.

E14 "The inverter is protected by the detection ofground faults between the inverter output and themotor during powerup tests. This feature protectsthe inverter, and does not protect humans."

Sounds likely that there is a break in the cable which has flashed at the GX16 connection causing the split in the pin to draw together.

[JAZZCNC]

Been there done this and it cost me VFD + Spindle.!! . . . . . . I made the strain relief from start but temp removed spindle to check some spindle mounts I'd made for some one as didn't have a spare spindle handy but didnt put it back straight away as I had more to make then it got forgot until it did excatly what yours did.!! . . . . . Hope you haven't fried the spindle as well.!

[IanParkin]

I just searched for your model of inverter and page 65 had the error messages and how to reset (not like you refered to )

[IanParkin]

This is the manual I looked at

http://www.inverter.co.uk/applicatio...v51-manual.pdf

[routercnc]

Hi Ian,

OK yes I've tried that. Press stop, activate the digital input configured as RST (this mean links terminal P24 to terminal 5), and turn off. I've tried this lots of times. Fault is still there on start up.

Note that I don't have the spindle connected (UVW terminals) and it still faults E14 (earthing of UVW), so something must be broken inside the VFD.

Looking at my options now:
Have a look inside
Send off for repair - economical?
Buy a new one - I see that the Chinese 2.2kW VFDs are about £90 on ebay (my VFD was £360!)

Question, can I connect a 2.2kW VFD to my 1.5kW spindle? That would leave a future option of a 2.2kW spindle to give me larger collets.

I think that spindle itself is OK because there is about 2.2ohms between each pair of pins. Not a complete check I realise but promising.

Thanks

[IanParkin]

I have not worried about connecting a bigger VFD to a smaller motor
and indeed on occasions the other way for a test off load

just set the max current appropriate for your motor

I have 12 vfd's driving bits of machinery in my workshops and only 1 chinese branded ( i think they all made in china now)
the european brands are easier to set up perhaps ....manuals seem easier to understand
But they all perform as expected
so in your situation I think I would buy a chinese one for £90 and look into having yours repaired as a back up
or buy a package of spindle and vfd for £220 ish? if you thinking of the 2.2kw one
Ian