Delta VFD-M / 2.2kw spindle - ground fault! - wiring help needed
 

I have a Delta VFD-M and 2.2kw spindle purchased from UgraCNC.

I have had no luck getting the spindle to move. I keep getting error "GFF" (ground fault) but can't figure out where the issue lies.

I have 220v single-phase power, with the Black wire connected to R terminal, White wire connected to T terminal, Green to Ground terminal.

On the spindle side, I have checked my cable for stray copper strands/shorts, etc. All looks good. Double checked the pin #s on the connector and wires and they also look to be correct. Pin 1 is connected to V terminal, Pin 2 to W terminal, Pin 3 to U terminal, Pin 4 to Ground (green screw) on the outside of the Delta VFD case.

Can somebody please help walk me through the setup of this thing?

In the US, I would expect 220V single phase to be delivered on a black and a red wire, possibly with the white as a neutral (not used in this application) and the green as a ground.

Do you have a meter, and can you tell us what the voltage readings between R & T, R & Ground, and T & ground are?

Or, can you work back up the line and explain or give a picture of where those power wires are coming from? Are you plugged into an outlet of some kind? Wired from a panel?

I suspect you may need to consult someone locally with some wiring experience.

Ground fault sometimes indicates reverse polarity of the supply active and neutral check your active and neutral polarity first. Transpose them if you are unsure.

Second it sometimes indicates poor insulation resistance. Often poor insulation resistance is caused by shaving of the insulation around gland plates through entries that are not grommeted. The best way to check insulation resistance is to use a Megga. Often the resistance will be high when you check with an ohmmeter but break down when voltage is applied. To test use a Megga connected to earth and both active and neutral of field wiring disconnected from motor. Test with Megga between active and earth and between neutral and earth and between active and neutral. If the cable is not damaged test the motor in the same way but omit the active neutral test.

You need to go back to your service panel and determine if your line voltage is coming from a 220v (double pole) breaker. If it isn't then you are attemping to energize your spindel with 110v power ( single breaker w/1black wire). The white (neutral) wire is not used. If you do not understand this then I advise you contact a licensed electrican.

All is definitely good on the power side. I'm plugged in to an outlet that was previously used with a MIG welder. It is a 220v double pole breaker. 2x20 amps if I recall correctly.

This was my troubleshooting process:

I started the VFD with the spindle cable disconnected from the terminals. everything runs and startup looks to be okay.

I reconnected the spindle cable to the terminals and pushed "run" and turned up the potentiometer. Again, it looks okay.

I then plugged the cable into the spindle and got the ground fault after pushing "run".

Reversed polarity of the incoming power to the VFD and tried all three above. Same outcome.

So my conclusion is that the problem seems to be in the wiring on the spindle side. The spindle is brand new, tested, confirmed working before it was shipped to me. http://youtu.be/xhS7-xkt0W8

I emailed Andy @ UgraCNC to try to get assistance with wiring, but according the the info on their site, he is out of the country until Nov 19th and may or may not reply to my email. I'm not even sure he has received my message.

I'm going to go work on getting my X rails drilled and tapped. Hopefully I'll get an answer to this before I'm ready to start cutting.

(reminds me - I need to update my build history! I have about 7 months of work I need to post photos of.)

First try with vfd ground to spindle disconnected, spindles usually have no ground wired on the 4th pin of the connector and your may be touching internally some of the phase wires.

On ugracnc site you can find an anatomy of the spindle and try to locate the problem.
http://ugracnc.com/technical-resourc...e-anatomy.html
Just open the top, or easier ... use a multimeter to measure pin 4 to all others for connection.

From the manual Gff

Ground fault :
The AC drive output is abnormal.
When the output terminal is
grounded (short circuit current is
50% more than the AC drive rated
current), the AC drive power
module may be damaged. The
short circuit protection is provided
for AC drive protection, not user
protection.

Danilo - looks like you were right! I disconnected Pin #4 and am no longer getting the GFF error. Thanks for the tip.

So naturally, my next question is: Should Pin #4 be connected properly inside the spindle and grounded?

If this is something necessary I will fix it. If not, I might leave it.

you can either ground to the machine frame or leave it disconnected, since the MM frame will be properly grounded if you follow what everyone else did during wiring :D

okay... now I can HEAR the VFD running (that high-pitched buzzy whine when the frequency is changed on the potentiometer), but I'm getting ZERO movement in the spindle.

It was my assumption that the VFD would be configured for my spindle, but I have no way to confirm that. The "manual" included with the spindle isn't any help. The VFD manual is comprehensive but covers all sorts of applications. Again, no way to know what the settings should be.

I have:
P03 = 400.0
P04 = 400.0

Not sure which other parameters are applicable to my spindle.

The word "spindle" is just a fancy name for a motor. thats it. there is really nothing to it other then 4 or 3 wires connection.

Yes, I get that it's "just a motor", but it's the interface between the VFD and the spindle that is unfamiliar territory for me.

P00 through P09 and P54 are the ones you should care about to get started.

Update, and some good news:

Andy from UgraCNC wrote back and pointed out a crucial mistake in my wiring. On the GMT spindles the ground is Pin #1, NOT Pin #4!

U-V-W on the Delta VFD are wired to Pins 2-3-4 respectively.

I'm up and running now.