Warco VMC mill

Hi everyone

I have just taken delivery of a new Warco VMC mill.

I have a curious problem that when switched on the fan runs and then when the spindle is switched on as soon as I increase the revs above 150rpm the main RCCB in the house drops out.

The workshop is wired separately from the house dis-board via a 40amp circuit and the main trip is 40amp and 30ma.

The workshop dis-board is a total of 40 amps and the main trip is 40ma.

I'm sure that many of you will know what is wrong and I would value your input before I do anything.

Many thanks

Richard2.

Is this a 3 phase motor powered by a VFD or a simple single phase motor? It makes a big difference to the diagnostics!

Andrew.

Hi Andrew

As far as I can make out from Warco it is a 3-phase motor with VFD.

I'm sorry that's all I can tell at the moment.

The Warco "manual" consists of 4-A4's with very little info - certainly nothing technical.

Richard.

Hi Richard,

Firstly I would check your trip is in tolerance, if possible use a neighbours supply and a quality extension lead and see if it still does it. Also you could have other appliances fridges etc that are already pushing the limit so don't automatically assume the mill is the problem just because it's tripping on speed increase.

I have had a faulty trip going out too early, they are probably designed when failing to be more sensitive as it's a safety device.

No doubt the leakage on the machine is increasing with speed but is it in tolerance?. I have a WM20 which more than likely uses the same set up. The motor cooling fan is on all the time is normal and very annoying. I have disconnected mine as I am not loading the machine, but will eventually put a remote switchor sensor on it.

Alan

Edited By Norfolk Boy on 08/08/2017 18:11:29

Edited By Norfolk Boy on 08/08/2017 18:12:11

Richard,

How far is your workshop? Just re reading your post. I would have put a separate 100mA trip on the feed at the main board to protect the cabling and have a local 25mA trip in the workshop and without getting into arguments about rules and regs exported a good earth from the house too.

Knowing how that's arranged may help, I am no expert but for every electrician I asked about my workshop supply I got a different answer.

Alan

Not sure if it's of significance but when I had my workshop wired they put a standard A type breaker in the consumer unit which used to trip once in a while. I later read it should have a C type breaker so I had it replaced and it hasn't tripped since.

I have a Warco VMC and it has no fan on it.

Hi Richard - if it does have a VFD then it's a new model of VMC (not even on the web site yet!), I'm not sure you'll find many people with the same version as yours. The fact that the VMC didn't have any electronics to go wrong has actually been a selling point, especially when you compare it to all the problems people have with the DC motors and speed controllers.

If you could get a picture or the model number of the VFD I'm sure a full manual will be available somewhere. It does sound like an earth leakage fault rather than an over-current fault. This is very common with the cheaper chinese VFDs.

On other forums (mainly DIY CNC forums where lots of the chinese 400hz VFDs are used) people check for this by running the VFD without an earth on the AC input side, obviously you earth the machine independantly for saftey - to be honest Richard unless you are experienced with machine tool electronics I wouldn't try this.

Another vote for the earth leakage from the VFD EMC filter tripping the circuit. My VFD powered lathe is on dedicated circuit with a 20A C rated breaker. I was specifically advised not to use a RCD with a VFD. I would recommend checking with Warco for their installation instructions. BTW my old school single phase VMC runs fine on a 13A plug on a standard ring main. That said a VFD powered one would be nice, should run much smoother.

Firstly, many thanks for all suggestions and help.

I now feel very guilty as I called in a highly experienced "sparks" and he eventually found that damp was running along the workshop supply cable.Also the house dis-board wiring is suspect. Having sorted it all out the mill is now electrically OK and runs quite happily at top speed.

The workshop supply is to be changed to armoured cable on Monday and the dis-board will be replaced.

I now have to replace a lot of tooling and the clamp set from MT2 to R8.

I do like not having to wind the head up and down between changing the laser centering device and the collet chuck - I push the handle and the table raises without any effort - marvelous for an oldie"

Also one-shot lubrication and an almost silent belt drive.

Once again thank you all.

Richard2.

Hi Richard - great that you have found the problem!

I'm in the market for something VMC-sized at the moment. Have yet to see any info on the VFD equipped VMCs so will be interested to hear how you get on with it!

Cheers,

Nick

Hi Nick

Thanks for email.

So far I am well pleased with the VMC but am going to remove the handle that raises the table as I am not happy with impaling myself on said handle every time I turn away from the lathe!!!!!!!!! Where the handle goes you can guess.

As there is power feed to raise the table I will simply put the handle on when I need it.

Will let you have more comments when I get down to serious use of the machine - probably later this week.

Richard.