[premier_industr]

Our Mori MV 45 has been shutting off unexpectadly.
Any ideas ?
It is like someone pushes the off button on the operator panel.
This will happen if the machine is sitting idle or in a program.
Most of the time the machine will power back up by pushing the on button.
Sometimes the machine will stay on for 10+ hours at a time, other times it will shut off after 15 min. of on time.
The machine is a MV45 with a Yasnac MX1 control.
Mori says that the problem is on the Yasnac side, or a 24 volt short somewhere in the wiring.
Yasnac says that it is probably the 24 volt power supply.
My question is this, if it is the power supply, wouldn't just fail completly ? ( and not power back up ? )
Also what other possible problems could be causing this ?
I would like to look at all options before replacing a $1800 power supply.
Thanks
Tom

[Egar Twins]

It could definitely be the power supply or perhaps a nicked wire somewhere along the 24v line. The intermittance of your problem points to this. Throughout your workd day incoming power fluctuates as much as 20 v AC on your main line. This fluctuation will trickle down throughtout your system and be evident also in the 24v DC supply, since this is fed off of the main line. Your 24V power supply never actually operates at 24v...it actually functions normally at around 19v, which is till enough to trip sensors, relays etc into functioning properly. If the power supply is dying, then it could be averaging around 15v which tiptoes along the line of your 24v system not functioning properly. When your incoming power goes through its normal fluctuations throughout the day from increasedload of additional machinery, air conditioning, etc, your output is probably dropping to around 14v which is just simply too low to keep your systems runnning correctly. Check the power coming in the power supply after your main transformer. It should read whatever your required AC power is (ie 208, 240 440). If you check the outgoing (DC line) from your power supply it should read no less then 19V for your system to function properly. If it is down in the 14-17V range your power supply is dying. ( You will need a volt meter to check this) If this turns out to be true ( which I believe it will be), you will need to swap the power supply. An OEM is going to run you around the figure you said 1800.00. However, a perfectly suited equivelant/aftermarket will do u just fine and will only cost around 200-300 bucks. Google search power supplys and find a suitable equivelant based on your incoming and outgoing power needs.
Post back if you need anymore help,
J

[Eurisko]

We had an identical problem with a Mori MV40.

Our problem was caused by overheating inside the control cabinet. Clean all of the exhaust and intake fans, replace the air filters, and clean the heat exchanger.

For a quick fix, you can try running with the door open. ( NOT RECOMMENDED )

Still not sure if there is a thermal shutdown circuit or a heat sensitive component, but I'll wager that heat is the problem.

[Egar Twins]

The thermally sensitive part you are searching for is the power supply...99% of all power sources (even the one in your garbage disposal) are thermally protected. Although cleaning fans and running with the door open may temporarily alleviate your problem( I have fitted a few of my machines with internal Air Conditioning units) excessive heat is a by product of worn electrical equipment trying to eek by and the damage may already be done. As the copper wears the unit has to work harder ( higher amps) and thus generates more heat. I would check and replace your power supply and then look for a long term cooling solution as excessive heat will also drastically reduce the life of any electrical component.

The erraticness of the error points to electrical failure

[dertsap]

We had an identical problem with a Mori MV40.

Our problem was caused by overheating inside the control cabinet. Clean all of the exhaust and intake fans, replace the air filters, and clean the heat exchanger.

For a quick fix, you can try running with the door open. ( NOT RECOMMENDED )

Still not sure if there is a thermal shutdown circuit or a heat sensitive component, but I'll wager that heat is the problem.

our mv40's as well as few other machines (new and old) do not like the hot summer temperatures , at times we will run the machines with the cabinet open and a fan blowing towards the controls ,when things cool down we close them all up again ,

i wouldn t consider it a fix , it's only dealing with the elements

[premier_industr]

We have had this problem in the past even at 65 -70 deg. temps.

But it seems as though it is getting worse.

Just today the machine shut down about every 15 min.

Even from a cold start in the morning.

I'm leaning more towards a keep relay that holds the control on, or the power supply.

My question is this, if the power supply is bad, wouldn't it stay bad ? ( dead )

Thanks again.
Tom

[Egar Twins]

Once the power supply dies completely...you are correct that is it...you will be lucky if the machine even fires up...As the coils are breaking down you are experiencing it "dying". If you are only getting 15 minutes...then you are probably close...I would run through the diagnostic I posted above just to confirm and then begin shopping on the internet... Power supplys can be had pretty cheaply. Consult your wiring diagrams to find out all remote, input voltage, output voltage requirements and then match an aftermarket to your machine. Act now, as it seems you are close to death on that thing.
Post back if you need any help finding one or installing them; I have done many of these. Remember, every single OEM part on that machine was made by someone else. The only thing the manufacturer did was put it together.
your friend in technology,
J

[premier_industr]

Egar

Could you please let me know of a source for a new power supply ?

The power supply is a CPS25N.

It is in a Mori Seiki MV45 machining center with a Yasnac MX1 control.

Incoming voltage is 208v.

Voltages going out are +15v, -15v, +24v, +12v, and +5v.

Thanks in advance.
Tom

[gar]

070726-1022 EST USA

premier_industr:

Have you proven that your power supply is the problem?

There has been a lot of conjecture in the comments. If possible you need some quantative data. Do you have a decent meter? A Simpson 260 is an analog meter that sometimes gives better information than a digital. However, a good Fluke digital is a better starting point.

Is the input to the power supply actually 208 or is it maybe 120 from a stepdown transformer? Or is the power supply a switching type that may have an input range of 110 or so up to 240? Voltage specifications are not enough to specify a power supply. You also need to specify the current rating for each output voltage.

If your current supply is a switching type in one package, then a problem on one output voltage might imply problems on other outputs. But suppose that this is not the case and only one output of the power supply was faulty, then you do not need to replace the entire supply. You just get a single output supply of the correct rating for that single voltage output and use it in place of the output from the existing supply. Most likely for the multiple output supply you have there is a single common.

If the input AC to the existing supply is lost whenever the machine stops, then it is difficult to pinpoint the cause.

Very likely your machine has a CRM relay (a master relay). This is usually turned on by a momentary closure of a pushbutton and a holding contact on the CRM shorts across the pushbutton holding the relay on until a normally closed series contact opens removing excitation to the CRM. CRM probably controls power to your multiple output supply. So you want to know if CRM drops out when your problem occurs. It is unlikely that power for CRM comes from the power supply in question.

Really you need an electrican familiar with your machine to look at the problem.

.

[Egar Twins]

Are these the actual readings from the supply or what the poles are labeled? I have a feeling that they are the labels...the data I need is actual readings from the output posts of the supply....this will tell me if the supply is kicking enough or not...of note...summer is the time that all good power supplies go to die

[bborb]

Tracing the ladder diagram will reveal multiple devices that are suspect to your problem. The electric schematic can also be instrumental for same. Do you have access to either of these?
A 5volt device failure or 5volt flucuation can be just as catastophic in this case. That control sounds old enough to use 15volt logic also, the same applies.

[premier_industr]

Update

Directly below the power supply are two axial fans that run off of 208v.

They were shot ( not working ).

So there was no air moving inside the cabinet.

I replaced the two fans and the machine has been powered up for over 16 hours with no shutdowns.

I am not sure if this was the problem that was leading to the shutdowns but I'm sure it is a step in the right direction.

Could the power supply have been overheating and shutting the machine down ?

In this warm weather I'm sure it doesn't take much to overheat it.

But we have had this problem with cooler temps 70 deg. etc.

But with no fan on the power supply, could the P/S slowly warmed up and shut the machine down ?

A buddy of mine used to work at a shop that never had any use for preventative maintenance.

Like cleaning the filters and fans on the electrical cabinets !

He claims that on a hot day ( 80 deg+ ) some machines would not even power up unless the doors were open with a fan blowing on the electronics.

Granted I'm sure that there were other problems with the machines, but it goes to show how much heat can affect electronics.

I'll keep you guys posted on how my situation works out.

Thanks to all that have been helping.
Tom

[gar]

070802-2225 EST USA

The answer is yes. Maybe even at 30 deg and no fan you could have problems. It all depends upon design.

I like to design for no fans and 140 deg ambient. This, however, does not produce small packages. Fans and/or insufficent heat transfer are a significant cause for failure of otherwise reliable equipment.

.

[bborb]

When bench testing electronics, its an "old school" practice to have a light bulb in the power circuit.
Fans are basically motors and a bad fan can sometimes "dim the light" so to speak.

[gar]

070803-0834 EST USA

bborb:

Can you explain your comment in more detail? How would you chose a bulb size for a particular test?

I assume you are putting the lamp in series with a load.

The following is background for those unfamilar lamps.

The near zero current resistance of a 120 V 100 W tungsten filament lamp at 80 deg F is about 10 ohms. I measured one at 9.7 ohms. At 120 V and 100 watts the calculated resistance is 144 ohms. This is a large postive temperature coefficient of resistance vs temperature.

One Edison carbon filament lamp that I have has a zero current room temperature resistance of about 300 ohms, this measured at 298 ohms. At 123 V the current is 0.62 A or a calculated resistance of 198 ohms. This is a negative temperature coefficient and and a much lower coefficient than tungsten.

.

[bborb]

Hi gar,
I first heard of the practice at ITT from the older instructors, we never did it. I was mostly mentioning it to set-up the metaphor that a bad fan can be a "light dimmer".
I've stumbled across the reference to inserting a serial light bulb for troubleshooting purposes several times while I surf electronic documentation, heres a link but there are several more if you search hard enough (Google).
http://www.repairfaq.org/sam/tshoot.htm
HTH

[premier_industr]

It appears that the problem with our machine was an overheating problem in the control cabinet.

By opening the cabinet doors and putting a fan on the electronics it seem to run fine.

I don't like the idea of leaving the doors open, with my luck a bird will fly into it and start shorting out the electronics.

Has anyone here retofitted their control cabinets with air conditioners ?

Where is a good place to find one ?

What kind of a price range ?

[gar]

070812-222 EST USA

premier_industr:

Here is just one source I found on a Google search:
http://www.adproductsco.com/kooltronic_ac.htm

Try calling a local industrial electrical supplier like:
McNaughton-McKay Detroit. Their web site was no help.
Madison Electric Detroit
Try Hoffman directly. Their web site was no help.
Try any Hoffman dealer.

Do not use a compressed air type cooler. Way too costly to operate.

Maybe just a heat exchanger will work.

However, I suspect a more basic problem resulting from marginal components exists. But, an air conditioner may be expedient.

.