Combivert......

[diverjohn46]

The main spindle drive on the Easiturn just went off, but I can't find any power going to it. It seems that there is a relay (Marked R1 on the circuit diagrams) and that there is no power getting past this point.
Has anyone any ideas as to how this relay is controlled?
ANy ideas would be very welcome!

[Steve]

I had a quick look and cannot find any EASITURN circuit diagrams to look at so cannot help.

Can you scan and post the diagrams here and we could then advise what R1 is?

[Martin]

Easiturn PNC3 electrical drawings.

It does appear that the power to the drive comes through contacter R1.

[Steve]

Right.

The Relay R1 disconnects the supply from the drive. R1 is operated when the control supply voltage is present and the Spindle Overload is not tripped and the drive is not in a fault condition.

Things to Check:

You should have mains power to the Combivert whenever the machine is on.
Check on Pins T1 (L) and R24 (N) should be 240VAC

There is a spindle overload wired in series with the motor. This will have a trip reset on it. Make sure that it is not tripped.

The control circuit is fused so check F3 is OK. I am not sure of the control circuit voltage as its not shown but should be labeled on the Relay coil of R1.

Measure the voltage at the Control Transformer at pins 7 - 9 (This is the control voltage and will be AC)
Using Pin 9 as a reference for the next checksnow measure at 67.
If the control voltage is here then the fuse is OK.

Now measure at Wire 27 or FLC on the drive if the control voltage is here then the Overload is not tripped.

Now measure at FLB on the drive if the control voltage is on FLC and not on FLB then the drive is indicating a fault.

All this circuit is show on page 3 of the diagrams as supplied by Martin.

[diverjohn46]

Well, I found the first problem! The fuse F3 had blown. But, the replacement blew immediately. Now, I removed the cooling fan which seemed to have a problem. But it now seems that the problem is in the motor overload relay which is permanently engaged. This is blowing the F3 fuse and preventing the motor drive relay from engaging (this 'rattles' as the overload relay cuts in) I think that the relay has been damaged by the problem with the case cooling fan.

Now I need to work out if it is the relay that's the main problem or if there is a problem with the Combivert which has caused the major problem with the overload relay!

do I buy a relay only to find that I need to buy a replacement VFD!?

[Steve]

Hi,

Sounds a bit strange.

If F3 has repeatedly blown then the chances are there is a short somewhere.

Wire 67 feeds the coolant and lube live as well as the spindle overload. A short anywhere on this circuit could cause the problem.

Disconnect wire 67 from the OLMM and then try and replace the fuse. If it still blows the fault is nothing to do with the spindle circuit and you will have to start tracing the wires to the coolant and lube pump.

If the fuse does not blow when the OLMM is disconnected.

Reconnect then disconnect wire 27 from FLC on the drive. Power back on. If it does not blow reconnect 27

Now disconnect 73 from FLB on the drive. If it still does not blow then reconnect.

Now all that is left in circuit is the coil of RL1 and the RC suppressor on its coil. I would first remove the suppressor and see if that is the cause.

Let us know what you find.

[diverjohn46]

Thanks guys.
I'll try and track it back through once i've got rid of the dreaded lurgy and can get back to the workshop!

JOhn

[diverjohn46]

Well, not got the brain working well, but got into the workshop and had a go.
The trail left the answer as being the R1 relay! This was not what I've expected from comments on other strings about the probability of an issue with the (20+ year old)Combivert if the e-stop was used!

So it seems that the combivert is OK, but need to have a look at the R1 relay to see if I can find the problem with this and if it's fixable or I need to get a replacement!

John

[diverjohn46]

OK, the relay has been removed and the coil is short circuited !
The relay is a Benedikt & Jager k2-09A10. These are still available so I'll try and get hold of a new one.

[Denford Admin]

I guess you've already sorted something, but Maplin or local electrical wholesaler, should be able to provide an equivalent relay.
Make sure the coil voltage is the same (prob 24 volts DC) and diode suppressed (if the other one was - it may have a diode across the coil terminals or one built in to the relay...).
Also look out for the same relay contact ratings (eg 12Amps at 250volts AC)

[Steve]

Glad you have got it sorted.

The relay is certainly a cheap solution. Any relay will do but I think the coil has to be 24V AC.

Let us know how you get on

[diverjohn46]

Hi Guys,
well a trawl through the 'web put me onto a company called Spartan Controls in Slough. They have a list of the Benedikt & Jager relays on their site and following a quick phone call to some very helpful people on Monday morning and a confirming e-mail to ensure the correct info was sent/received, supplied the correct B&J parts, (though now marked IMO) So a new motor control relay and overload to the original spec total cost of £ 50.00 and arrived in the post on tuesday morning!

One of the nice bits was the fact that the overload relay clicked straight into the housing clip that held the original 1984 overload....

If anyone is contemplating getting these bits and want the original spec they could do worse than speak to Spartans (http://www.spartans.co.uk)

now got to sort out a few other bits I started on before I get it up and running again!

john

[diverjohn46]

Well, finally got to re wire all sort of bits and got power back onto the lathe. But still no response from the spindle.

I've looked at the Combivert, and although I've got the 'power' LED lit, there is no '0 volt' LED lit. There is no response from the spindle when the computer tells it to move.

Now, I've got the control voltage, mains power, and as suggested checked the control voltage is on both of the connections for the 'fault' indicator. I've also got 240 volts coming out and through the overload relay.

My feeling is that there is a fault somewhere and that there is no control giving the variable frequency. My feeling is that there is 240 volts coming out, but at such a low frequency that there is no movement.

ANy ideas??

John

[Steve]

Hi,

So you have 240V on the L and N terminals?

You also say you have a control voltage what is the DC voltage on REF measured to COM?

What reading do you get from COM to PP? This should be 10V

You could try disconnecting all the wires from COM REF and PP then put a link from PP to REF, This would give a maximum demand and the drive should run at full speed when enabled.

[diverjohn46]

Hi Steve.

I've got 24.5 volt AC on FLB and FLC referenced to '9'. This gives the correct action of both the overload and motor control relay.

I'm getting 0v between com and ref, the com-pp differential is 14.5vdc.

I'm also getting a full variable from the pc to the combivert of 5 volt dc, but still not getting any response from the combivert. Still not getting a 0v indicator LED. I shorted as suggested between ref and pp but still gave no response when the spindle was enabled with the software.

I've tried checking the resistors and capacitors on the main panel and all seem to be giving the right values through the 'meter.

I'm starting to think that it's probably a fault on the unit. I'm getting the distinct impression that, failing the ability to diagnose to component level, the unit need replacing completely.

John

[diverjohn46]

Well, I finally decided to change the combivert and managed to get, via the 'inverter supermarket' a WEG CFW10 inverter. This I've used to replace the Combivert and it wires in with very little change. The only thing that I need to change is the wiring of the overload relay to ensure that it cuts out the feed to the motor which it currently doesn't. as it has a single output on a relay for fault conditions.

However, even as it is I've run the lathe under the computer control and it's working well, even without having had the opportunity of tuning the drive as yet.

[Steve]

Great!

Glad you have finally sorted it out.

[diverjohn46]

As a postscript.........

It was all my fault!
I had miss-wired the coolant relay circuit and fed it 24vdc( don't ask!) instead of just putting a small relay across the contacts - this caused all the grief!

When re connecting everything I found that what I was about to do didn't seem right, I went back through the diagrams and saw immediately what I had done! Idiot!
Expensive mistake to make! The only surprise is that it took so long to manifest itself!

On the plus side, it is all working very nicely and I don't have to worry about old electronics!
(just need to finally sort out the cross slide backlash)

John

[Denford Admin]

oops ! at least you can rely on it now for another 20 (?) years