Machines constantly blowing boards on startup, cant figure it out

[Al_The_Man]

I am switching from 240VAC 3-phase high leg delta to 208VAC 3-phase wye. Right now we have our machine transformer taps set to lower the incoming voltage being fed to the machine controls to around 200~210V since the 240V is to high. So by changing to 208V we will have to switch our taps around but it should cause no problems. If one or two machines arent happy on the lower voltage i could easily install a buck boost tx for that particular machine. I dont expect to have any issues but murphys law im sure will come into play.

I guess the reason i thought the utility bill might change a little is from running lower voltage which in my mind means you need more amp draw to make the same amount of watts at the motors. More amp draw means slightly higher temps and less efficiency doesnt it?
.

As a general rule, machines manuf in N.A. tend to be designed for one (domestic) voltage, but any that are either European or Asian origin, especially from Japan such as Mazak, Fanuc, Mitsubishi etc, tend to have internal transformers for secondary voltage tuning, in Japan, the common control voltages are 100vac and 200vac, so often the internal controls run on this voltage.
Consumption is based on Watts, this is a product of Amperage and Voltage, If you were running on the high voltage side previously, your bill should should actually be lower if anything, as your load demand has not changed but in your case if you dropped the voltage, therefore the product should be lower.
In any case if the problem is cured, it will be worth it.
Al.

[wizard]

Wizard - I agree with your comments about the electrician i am using but the reason i am using him is because i know for a fact he is the most knowledgable electrician in our area when it comes to machinery and factory wiring. I have used him many times over the years and almost every factory in our local area uses him exclusively for this reason.

The way you portrayed this guy left me with the impression that he wasn't very Hungry as a contractor.

I am switching from 240VAC 3-phase high leg delta to 208VAC 3-phase wye. Right now we have our machine transformer taps set to lower the incoming voltage being fed to the machine controls to around 200~210V since the 240V is to high. So by changing to 208V we will have to switch our taps around but it should cause no problems. If one or two machines arent happy on the lower voltage i could easily install a buck boost tx for that particular machine. I dont expect to have any issues but murphys law im sure will come into play.

Maybe it is me put I'd like a detailed plan of action or at the very least a check list before I started anything. What you intend to do is a lot of work, as such it would be best if attempts to minimize looses ends are made. On the other hand maybe I'm imagining bigger plants than you really have.

I guess the reason i thought the utility bill might change a little is from running lower voltage which in my mind means you need more amp draw to make the same amount of watts at the motors. More amp draw means slightly higher temps and less efficiency doesnt it? Maybe its a small enough amount to not really matter.

Yes you could get some additional looses due to power varying with the square of current in resistive circuits. However you are only going from 240 to 208 volts AC so the change in current draw and thus looses in wiring shouldn't be that noticeable. It isn't like you are dropping from a 480 or 600 volt system.

If you have any machinery with large AC heating loads you need to consider the possibility that those machines might have issues. Again in the power in the circuit varies with the square of the voltage in this case. So a small drop in voltage can impact things like mold machines, curing ovens or anything expecting to turn electrical power into heat.

I ran into a situation once where over the holidays some maintenance was done on some facility equipment which apparently resulted in changes to transformer taps. The manufacturing people came back to work and called in a problem on a solvent reduction oven "that wouldn't heat up". The machine obviously wouldn't reach set point but nothing obvious was wrong. The nominal voltage to the machine was slightly low, apparently the result of a couple of volts change in the line voltage. Obviously a machine that was running at the limits of its capability as it could not make set point due to a modest drop in line voltage.

In any event the point is sometimes unexpected problems show up.

Rcaffin - That is the main reason i have chosen to switch our power supply. Im hoping there is a problem with the current transformers and putting new transformers in place will eliminate that possibility. I could have just had them replaced with the same high leg delta setup that we have now but
1st we have no need for the high leg,
2nd its not likely but is possible the high leg is causing problems,
3rd unless i could prove that the current transformers are faulty i doubt the city would replace them just to see what happens.

So why not. If this doesnt solve anything at least i know the transformers arent the problem and i need to look elsewhere.

Even if it doesn't solve your problem I'd have to believe that you are better off in the long run. At least from the maintenance standpoint I've found wild leg systems to be a pain in the you know what.

[GITRDUN]

Finally have my main shop running on the 208V wye voltage. Heres the setup we now have, the incoming power lines are coming from the utility pole and going into a 480V 3-phase wye transformer which we have been using for a few years now. This transformer powers a bus bar in the main shop which feeds our 440V machinery. Now we have a second transformer installed which is being fed from the 480V transformer, and steps the voltage down to 208V. The machinery that was previously powered from the 240V high leg delta is now running on the 208V wye transformer.

We spent about 3 hours going through all the machines and adjusting tx taps and checking that all machines are happy.

The city is supposed to begin the installation of switching the transformers for the other building pretty quick. So right now i have one building on 208V wye and the other still on the 240V high leg delta for now.

Time will tell.

[GITRDUN]

Ok i have an update and another riddle.

The main shop which is now running the 208V WYE power had a weird occurance this morning. When we came in to work and powered up the machines 3 machines came on with alarms that wouldnt clear. Same old story. Also one employee noticed his radio wouldnt come on. My maint man checked voltage on the 110V outlet and it checked fine, then checked all three legs of the 3-phase and checked ok from phase to phase and also phase to ground. After about 2 hours he noticed the power light on the radio was on so he turned up the volume and it was working fine. So we then turned the three machines on and two of them came on and run fine with no alarms, one had a breaker tripped in the back but nothing blown. The third machine has the spindle drive blown up.

Im not quite sure what to make of this but no doubt its an indicator as to where our true problem lies.

[Al_The_Man]

Do you have any industrial neighbors that are experiencing similar problems?
Al.

[RCaffin]

Now that is really wierd.

Questions:
Do you know what can trigger any of the alarms on the machines? What were they sensing? That you could not clear them suggests a continuing problem there in the morning.
Do you know whether there was power to the radio when it would not turn on?
Can I assume that the blown spindle drive was damaged at the inputs again?
And of course, as Al suggested, what have your neighbours seen?

I recollect that you had acquired a data logger - do you still have it? If so, can I sugest it be hooked up permanently to your main board. I don't know what is happening, but I have this really nasty suspicion that your incoming grid is bringing all this stuff into your factory. You need the data from the logger to verify that. Yes, a serious problem on the grid could explain the really bad damage from the high-leg delta connection you used to have.

Cheers

[GITRDUN]

We are the only manufacturing facility in this area of town.

The alarms will usually be random axis alarms or power supply alarms and sometimes will change to another alarm when you hit the reset button.
I dont know that there was power to the radio but we checked the power on the 110V outlet where the radio was plugged in and it had power but the radio would not turn on, it has a red dot to show its on and the dot was not on. After a couple hours someone noticed the red dot was on and checked the radio and it was working fine. Also had a cordless phone plugged into the same outlet and it is toast.
The blown spindle drive has two drive modules bad and a hybrid chip on the electronics board.

I havent been monitoring the power since we had it changed over, i figured if we had no more problems then the problem was solved. Obviously its not. I will start recording again.

What gets me is we knew there was something going funny with the electric and we were unable to catch it by checking voltages with a volt meter while the problem was going on. Im about ready to call the exorcist.

[RCaffin]

Also had a cordless phone plugged into the same outlet and it is toast. ...
we knew there was something going funny with the electric and we were unable to catch it by checking voltages with a volt meter while the problem was going on.

Sounds like transient high voltage spikes punching through. They could be coming down the line from elsewhere. They would not be seen by a voltmeter, but your data logger should record them. The source - could be anything.

If the data logger shows lots of bad transients, you can moan to the supply company, but it may be hard to get them to make the source clean up its act. In that case you can, at some expense, install either heavy spike filters or ferro-resonant mains conditioners.

The spike filters are cheaper but not quite as good. They clip the transient peaks off. I would suggest getting technical advice from a vendor for these - you will need good earthing with them. They may have to be treated as semi-consumable if the transients are really bad. (In which case, really ouch!)

Ferro-resonant mains conditioners are more expensive, but I can vouch that they DO work well. We ended up with a stack of them at one place I worked for many years: completely solved our problems. The Sola brand is a starting point. We were using 0.5 kW, 1 kW and even a 3 kW unit. But they come much larger than that, up to many kW, maybe even enough to drive your factory. See
http://www.solahevidutysales.com/sol...onditioner.htm

You have my sympathy.

Cheers

[GITRDUN]

Can you get small 3-phase ferro resonant conditioners that connect at each machine or is it more advisable to use one large one to connect to the incoming power line? Thats something i will definately look into.

[RCaffin]

Can you get small 3-phase ferro resonant conditioners that connect at each machine or is it more advisable to use one large one to connect to the incoming power line?

Both are available. I suggest that the first step would be to work out how much power each machine requires, how much the factory requires, and get prices for both approaches. Leave room for expansion when budgeting the single large unit. Tech advice from the company is highly recommended.

Having individual units, one per machine, gives greater flexibility. However, it might not save that radio or the phone base station!
What you could do is put one FR unit on each machine and some large spike suppressors on the various distributions to other gear around the floor. Or run local outlets off the unit on each machine, if suitably sized. But ... maybe one big unit would be cheaper.

Cheers

[mactec54]

The alarms will usually be random axis alarms or power supply alarms and sometimes will change to another alarm when you hit the reset button.
I dont know that there was power to the radio but we checked the power on the 110V outlet where the radio was plugged in and it had power but the radio would not turn on, it has a red dot to show its on and the dot was not on. After a couple hours someone noticed the red dot was on and checked the radio and it was working fine. Also had a cordless phone plugged into the same outlet and it is toast.
The blown spindle drive has two drive modules bad and a hybrid chip on the electronics board.

Sounds like you had a lightening strike over night, to do the phone in on the 110 outlet, this could of also set off the alarms on the machines

How is the Grounding set up in the building, this is were you should be looking, at this point

[Al_The_Man]

We are the only manufacturing facility in this area of town.

The alarms will usually be random axis alarms or power supply alarms and sometimes will change to another alarm when you hit the reset button.
I dont know that there was power to the radio but we checked the power on the 110V outlet where the radio was plugged in and it had power but the radio would not turn on, it has a red dot to show its on and the dot was not on. After a couple hours someone noticed the red dot was on and checked the radio and it was working fine. Also had a cordless phone plugged into the same outlet and it is toast.
The blown spindle drive has two drive modules bad and a hybrid chip on the electronics board.

I havent been monitoring the power since we had it changed over, i figured if we had no more problems then the problem was solved. Obviously its not. I will start recording again.

What gets me is we knew there was something going funny with the electric and we were unable to catch it by checking voltages with a volt meter while the problem was going on. Im about ready to call the exorcist.

After what you had done, It certainly sounds like something upstream of your facility.
If it is very short or transitory, by the time you put a meter on it has passed?
If there were problems at the sub station feeding your line, I would have though others would be in the same fix, maybe time to get the chart recorder out again?
Al.
.

[mactec54]

GITRDUN

90% of all industrial problems with power supply is poor Grounding & Bonding within the Building, from the source to the machines, most of your problems point to this, no amount of accessories added to the power system is going to solve this problem

Start with a complete go through with the Grounding & bonding of everything in the building,to correct what is wrong in this area, You need someone that knows what they are doing to put it right

[Al_The_Man]

GITRDUN

90% of all industrial problems with power supply is poor Grounding & Bonding within the Building,

If you read the history of this saga, including the previous thread on it, the grounding issue has been thrashed over many times.
Al.

[mactec54]

Al_The_Man

By what I read in different posts about there grounding, I could see that there were problems in this area, that were not corrected, or even talked about, I can say without a doubt that this is were most of his problems are

[GITRDUN]

On the subject of grounding. Is it advisable to have a ground rod at each machine and also the ground wire from the service connected to a machine or should it be one or the other? I have heard of possible ground loop problems from having ground rods at each machine but its all over my head.

[mactec54]

GITRDUN

The Ground Rod at each machine need to be bonded to each other & then to the main Ground rod at the main power input to the building, There is more to it than just this, here is some good reading on the subject, Having this all correctly done in your building, will most likely solve most of your problems

[RCaffin]

A lightning strike is not impossible. We have had them, at work and at home.
One girl at work came back to the lab a bit shaken one day: she was sheltering in an outside doorway when lightning hit the tarmac outside. Rather loud. With great foresight I had linked the various buildings with fibre optics for the network, rather than copper wire.
I came home one day to be greeted by an apologetic wife: she had been just a bit too slow to unplug the modem when the storm hit. It was a bit cooked (like totally), and the interface on the computer was also damaged.

Some places do have a problem with grounding. We do. So I dug a wide hole and buried some stainless steel welded mesh - about 1/2 metre square, 3 mm wire. That has helped us a bit. I also ground outlying workshops locally.

A FR transformer solves all of that. Btw, don't confuse an 'isolation transformer' with a FR one. Isolation transformers do not block most of the spikes. However, an FR does contain an isolation transformer.

The 'Grounding and Bonding' doc posted by mactec is a very good one, and it may be worth your while to read through it once. Certainly, grounding is far more complex than most think. One point from it should be remembered: you should have the incoming neutral connected to ground at only one place in the factory (at the board). However, as far as I know, there is no reason why you cannot separately ground the frame of every machine in the place, as well as tying them all to the powerboard ground. That is roughly equivalent to using multiple earth stakes.

Especially worth reading is the 2nd bullet point on page 27. It may echo for you.

Cheers

[Al_The_Man]

While the importance of proper grounding is paramount, From all that has happened so far, I suspect it is something other than a grounding problem.
More in the realm of an anomaly in the power distribution.
Symptoms from Grounding etc may occur at any time, these machine failures appear to only occur at machine power up time.
Also see the sidebar, Myths of ground rods.
Al.

[neilw20]

Is there a possibility that the failure occurs at switching off? Depending on the loads, the machine itself can create big transients at switch off.