Emco-Turn 340 - Shutting down on me

Today I turned on machine and found a problem in that the machine powers down, at the start of a cycle. However, if I leave machine spindle running it will run without a problem.

I started going over the wiring hoping to find something loose, but didn't find anything.

I checked the power coming into the machine and seems fine.

Now what I did come across is power going to the Power supply for the CPU seems to be off. I think it is supposed to be 24VDC, as it is labeled as such. I read 19.5-20VDC during and prior to the start of a cycle and drops down to 18.5 as machine starts a cycle. Can this be a problem, less voltage, heating up CPU and shutting it down? We are doing large batches of small parts, constant start and stops.

Put a call into service, but can be awhile before I hear back from them.

Any help would be appreciated.

If it is supposed to be 24V, then you are pretty low. But to clarify one thing... You have another supply in there someplace. Your CPU won't be running at 24V. It will be 5V or 3.3V as those are normal logic levels. For something as large as a CPU (and its associated logic), generally they have a separate 5V (or 3.3V) supply that goes to the board. Yes, you *can* regulate from 24V to 5V, but I'd be a little suprised if they did.

Nonetheless, the 24V level could certainly cause problems. I think I'd try to figure that out.

To further the discussion Doug has introduced... When an EmcoTronic goes down (main drive fault), it is a PITA. You have to shut down the power to reset the fault. Argh! There is a resistor you can change that, theoretically, will reduce the sensitivity to the power fluctuations but it didn't really make much of a difference in my setup. You can also re-tune the phase angle boards for the spindle (again, didn't make a big difference for me). This is only germane for the EmcoTronic T1 and TM02 controls though. And, of course, you can also do what Doug is suggesting. Mine tripped at about 500 RPM though...

--Alan

Thanks for the responces.

The Emco has a Siemans/General Numeric 810T Control.

I was inserting the slower ramp up as you mentioned, think I'll try a G4 as well.

Wrench, You may be correct about the 5VDC to the CPU.
From what I remember Emco uses an external transformer to bump our shop voltage from 220VAC to 380VAC to the machine. Then they have an internal transformer to convert to 24VDC to go to the power supply board for the CPU. The CPU Power Supply Board then converts the 24VDC to what I believe is 5VDC as you mentioned. I am not really sure where the output voltage from the power supply board is, but the input is right out in the open and easily checked, hence my checking it.

Hey Sim, your 24VDC is too low and it will do funky things. The CPU power supply is under the CRT and has test points to check the voltage. The power supply runs off of the 24 VDC circiut from the machine. If the entire 24 VDC system is low go to the +5 taps on the on the control transformer in the main elec. cabinent. It's been a while but I think on that modle you change it there. If not I believe the main step transformer Emco supplied can be wired for + or minus - 5%. I think those older style transformers had three bundles of wires ( one off of each coil ) you should see some unused wires in each bundle and they should be labled. You can boost the incoming 380 and get the same results. What drives do you have? Baumuller, Indramat or other. A boost of the 380 could posslibly require tuning but most likely not. Also check the incoming power to the step up transformer and the 380 out. This for reason could have dropped and may be the culprit for the voltage drop you are seeing.

Hope this helps,

Dave

Heh CNCMEK,
You know my machine thats for sure. I have Contravers Drives.

I saw the +/- 5% at the transformer. I already have three wires attached to the +5%, guess that would indicate I'm out of adjustment.

The voltage coming into the machine from the transformer was 120 at each leg. That would give 360VAC, too low? or within tolerance?

I'll check voltages again in the morning. A check out the incoming line as well.

Thanks,

Before changing the taps, there are some things to think about here.... First, something we never asked should be cleared up... Are you saying 24VDC or 24VAC is low. It is very important. 24VAC is probably just taking your 380VAC input and running it through a transformer. In that case, yes, you can fiddle with the taps. Of course, you are best off checking that you have 380V on each line first! Fundamentally, a transformer won't change its voltage over time, which is the point I'm trying to make.

If you are talking 24VDC, however, then all bets are off. Changing the taps on the bump-up transformer might *not* be the thing to do. In fact, it might damage the machine. The 24VDC would get converted through a power supply, not a simple transformer. And that PS could easily have problems or may need to be readjusted. The proper thing to do in that scenario would be to resolve the PS problem, *not* arbitrarily raise the input voltage to the machine.

--Alan

Wrench, most of the full blown Emco cnc's direct rectify off of 18 VAC to generate the 24 VDC. It was a common practice to set up the machines so you had 390 - 400 VAC output from the main transformer due to low 24 VDC problems. The machines get a little squirely around 21 VDC and below. Usually turret problems. actuaully used to shoot for 25-26 VDC to handle to drop when a lot of stuff was going on at once in the cycle or due to shop drop in voltage due to a lot of equipment running durring the day and not much at night.

Sim, If you are getting 360 off of the +5 taps on the main it seems like your incoming to the transformer is 208 not 220 VAC. Give it a check. The transformers Emco supplied had wires in the bundles i think for 208,220,240,460 and 480. Been a while but I think that is true. I was an Emco factory tech in the mid 90's. Ran the east coast for 2 years and have been to a lot of shops in the NYC and NY state area but I don't recall Staten Island. There was a shop in Floral Park on Long Island that had several 340's. Forget their name but they made gears. Anyways, Wrench is advising caution and I agree with him, I am just trying to get as much info. as possible. ( And refresh my memory, it's been a while ) I don't believe you would need the expense of a service call to resolve this but in the end you will have a lot info. to give to Emco over the phone if needed to resolve this.

The old 340's were peculiar beasts. The 810 GA1 control has some differences from the later GA2 and GA3's. Most had the lable of Sinumerik(sp) rather than Seimens. Someone please correct me on my history if I have it wrong but I believe this was the first high power control from seimens and was a spin off of the General Numerics of years ago. I was told that General Numeric was a combination of siemens and Fanuc. I worked on some old Leblond CNCs that had this set up. All Fanuc motors ( yellow cap ) and drives and the General numeric control. If I remember it was the GN6 control. It had bubble memory.

Oh well, sorry to get of on a tangent just had some brain cells trying kick back to life . I hope some of this helps Sim.

Dave

Thanks again gentleman,
Its a great help to get a background on what may be going on. Also gives me a chance to get comfortable to what needs to be done and checked.

The +5% taps are on a transformer within the cabinet on the left center. It also has a large blue capacitor in the area. I mention this as when I had to replace the Power Supply a few years ago they had me check the capacitor connections.

Anyway, don't know what to check at the Internal Transformer so I haven't checked anything other then the connections.

I did check the voltage coming into the machine from the External Transformer and got 213-215 VAC from each of the 3 legs. I must have read it wrong yesturday. I will get into the External Transformer later and see how its hooked up. And I will recheck voltage coming to the External Transformer.

I should mention yesturday I couldn't run more then 10-20 pcs before she pooped out.
This morning it has been running contiuously since 6:30, its now 11:09, thats several hunderd cycles.

Voltage to the Power Supply Board is still low @ 21VDC and drops to 19.5-20VAC at start of cycle. But slightly higher then yesturday.


Cncmek,
We purchased the Emco used in 98 from Digital in PA, so it is most likely a machine you worked on, setup etc.

So its all your fault.... Kidding, small world huh. Its been a great machine for us.

Thanks again,
Carl

Checked power coming from transformer, its 360 VAC, too low.

Power going into transformer is 212 VAC.

Transformer seems to be wired up for 208 and I have "taps" to up the voltage to 385-390. At least that is what I measure at the taps. That should be fine except...

Now, pops tells me he thinks we have 220 or 230 VAC and not 208. Yup I'm confused.

I asked my electrian to come up and tell me whats what with the power, before I start poking around and re-wiring stuff.

Anyway, thanks again, maybe I found out why machine poops from time to time.

Carl

Hey Carl, were most of your flakey times during the summer? I have seen this quite a bit. EVERYBODY runs there AC and the grid will drop in voltage. It can happen un the winter also but not normally as bad a fluctuation in drop. I would bet money the whole problem with your sporadic machines problems in the drop in the main incoming during peak hours. If you can, check your main( input and output and all the taps) at night the later the better. You have a baseline from today this will allow you to how much of a voltage swing you have. Then you can figure what steps to take. Let me know what your electrician has to say. I have known a lot shops that had to change their external transformer wiring with the seasons due to this type of thing.

Also, by all means call Emco befor making a change it's always nice to hear the manufacturer say what you are doing is ok or not. Plus it's been a few years and I may be forgeting something.

Dave


P.S. What city in PA and what product did Digital make? Trying to remember if it's my fault or not.

Dave,
Electricain just said the same thing you did. Bad incoming power.

He just checked incoming voltage at 212 VAC and transformer was putting out 375 VAC. I think that would be the best I would expect from Con-Edison. Wish I had checked Incoming Voltage yesturday the correct way to get a better baseline, I just went from Neutral to each leg.

Anyway, voltage at the power Supply is 21 VDC and drops to 20 at the start of the cycle, no problems all day.

I will speak with Emco or my local tech about using the other taps at the transformer, Electrician said to leave well enough alone as Con-Edison tends to send spikes of about 220 VAC around from time to time.
Output Voltage on the plus side taps is 390 now and he thinks it may be too high if a spike or surge comes along. But he too said ask the factory technicians there advice.

As for Digital, its been 8 years since I have been there so I really don't remember the town, but know it was just a few minutes into Philadelphia coming from the NJ Turnpike. They made mostly medical implant parts, lots of SS and 17-4ph being run. Greg and his #1 I think was either Dave or Jeff are the people I dealt with. They had several Emco's when I went by. Nice people, clean shop.

Thanks again for the help, and yes I would ask Emco and/or my tech prior to doing any modifications.

Carl, glad I could help you and would do so again any time. Darned if I can recall the company. I've been to hundreds of them and it get to be a blur at times, most likely I have.


Take it easy,

Dave

KNow the blurred feeling, don't do a brain strain on my account.

Thanks again, hopefully you uncovered the cause to my sometimes flakey machine .

Doug, I understand about working the holidays you do what you have to make it and be succesful. I have voltage and frequency problems effect a lot of different types of controls and drives. Of everything I've worked on I think the Emco's are right up there as far the 24VDC systems being finiky. The mitsubishi's seem to real main voltage sensitive. They are listed as 208 - 235 VAC if you are outside of that window you can have some serious problems, especially on the high end. By far the most robust control and drive packages I've dealt with are Fanuc.

In my experience you could almost split it this way. The Aisan machine tools seem to less problematic that the European ones. I believe this has a lot to do with, for lack of a better term, build phylosifies(sp).

The European stuff has great technology and very ( in a lot of cases overly ) complex components and a lot of them look great but are not very depenable IMHO. You can almost tell by the country of origin what you are going to run into and I think a good comparison is a look at the automobiles they produce. The Italin stuff I have worked on was good looking but the designs of the components complex and under built. The German machines were pretty reliable but very complex in some instances. You could look at something and think " why did they do that? it could have like this a lot simpler " The Swiss machines tend to be like their watches. Precise, compact and a whole lot of stuff in a small package. As an example there are two divisions of Guildemiester a German and an Itailin. From what I have been told avoid the Itailian ones.

I really think the car analogy is a good one. Pop the hoods and compare a Mercedes to a Ferrari. Look at the bodies. Compare time in the garage and what it takes to keep them running.

Now the Asian machines tend to be strait forward strong, precise and somewhat simpler to work on. You can again look at the country of origin and see what you are going to get for the most part. Most things out of Japan tend to rock solid in all aspects. Korea puts out some good machines but they aren't as refined, they are still coming into there own.You can see it in there components. Some of them are a little rough as problems are found they are addressed and corrected. The ones from Tawain are, for the most part,are cheaper and kind of rough as far as finish is concerned. China is behind them. The one thing I found with the Aisan vs. European builders is more of a willingness to change, to admit to a design flaw and correct it quickly.

Now back to the cars. Compare a Toyota to Mercedes. They both are good cars. Look at the body styles and pop the hoods. See how the components are arranged. One is a lot more complex and expensive but the both get the job done and will run for long time. Personally I'll take the price tag and repair bills on the Toyota.

Damn, that was long winded, sorry. I could go on for a while on this subject having worked with a lot of different builders and having been to there factories and seen them built and been given factory traning on maintenence. One thing for sure is the Europeans have the better food and beer.

Dave

I like that analogy, seems to fit quite right at many different levels too.

Does age have much to do with the machines sensitivity to voltage.

Hey Sim,

I feel that the older anolog drives tend to be more forgiving than the newer digital ones. Just look at the amount of older machines out there still making parts.

However, I believe the control end of things is more solid now. At the very least the dianostic packages are much better and it is a lot easier to come back from a major problem once one occurs. Gotta love popping in a flash card and bringing a control back from the dead vs. hand typing all the crap back in.

Take your 340 for example. That has a Seimens 810 GA1 version control. Those were a bummer to reload. The GA2 and GA3 versions were a LOT easier and could be done in about a third of length of time. I have run into occasions where it took 3 or 4 attempts to get a 810 GA1 to take all the data and keep it. By the way if you ever need a back up for your control I have several on floppy I would be happy to send one.

Take care,

Dave