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zapster
10-13-2006, 09:21 AM
Well the welder is back to tripping the breaker again..
i'm lost when it comes to these problems...
it was suggested that the breaker although new could be defective...
its a 60 amp breaker..

my boss read the plate on the machine and said it should have a 100 amp breaker instead..

heres what the spec. plate says on it...

amps 250
max ocv 80....volts 30
% duty cycle 40
volts 200-230-460
amps 110/96/48
phase 1 hz 60


and thats what the plate looks like also...

any ideas on the breaker size??

...zap!

Shane@profab
10-13-2006, 09:57 AM
now steady there, we dont want people getting upset.....hahaha

sorry, back to your post - yes it would your breaker is too small, the important info off your nameplate is those three voltages and the three amp ratings (I didnt quote your message so I cant see them now) but the lowest voltage was 200v and the amps was 100, as teh voltages goes up so the amps come down (cos elec power stays the same and is the product of volts and amps)

Your boss said you needed 100amps, I assume thats cos you have 200 or thereabouts supply to your shop.
Be carefull about just putting a new breaker in, you need to be sure the cable size is correct for the breaker you want.

Hope that sorts that upsetting feeling.....probably just replaced it with a depressed feeling hey?

Birken Vogt
10-13-2006, 10:16 AM
You have to specify what voltage you are running to be able to start answering the question. Also for what size wiring is in the building and what size wire is the cord to the machine.

Birken

prop-doctor
10-13-2006, 10:20 AM
i would say the same
V 200-230-460
A 110- 96- 48------(96 A at 230V
but it is confusing why V-200-230-260 shouldn't it read one voltage
if it's a single phase an a 220/240v machine
you might want to check the voltage under load at the panel
but it has been30 yrs since i have realy messed with commercial/industrial electric loads

zapster
10-13-2006, 10:26 AM
thanks for the replies guys..

the volts is 220
we do have 200 amps feeding the breaker panel..
the wiring and panel is brand new and the welder is hard wired to the panel..
the cord is plenty heavy duty so that should not be an issue...

the thing about it is that sometimes i can weld for hrs and have no problems..
but one day last week i welded for about 5 hrs before it tripped the breaker..and when i went to re-set it it was pretty hot....

but like today i touch the footpedal and pop!
i've had the top off the machine..i cant see any arcing or anything like that when this happens...

...zap!

prop-doctor
10-13-2006, 10:39 AM
if breaker was hot then i think of loose connection at breaker or wire loose
or just bad breaker
try new breaker, check for tightness at lugs
hope you get it figured out ZAP
good luck

Birken Vogt
10-13-2006, 10:40 AM
A breaker can only be operated at 80% of its rating continuous reliably. You are probably operating near 100% most of the time on a 60A breaker.

As they get older they generate more heat internally and that causes them to trip sooner because they trip based on heat (and other things)

Once a breaker has opened under load it can never really be trusted again.

So that probably will serve to explain why your problems with breakers.

Now on to the load calculation.

Your welder rating panel states 96A so sizing the lower end of the breaker is pretty easy. It needs to be at least 100A to cover the load. The 80% does not apply here because the welder is rated 40% duty cycle.

For the cord the amperage figured is 61A. 4ga SO cord is rated at 70A so that is what it should be. The highest you can go on the breaker is 150A since you are allowed to go double the cord's rating (140A) and then the next size breaker up which is 150. But a 150A breaker is big and expensive so most likely you will want either a 100A or a 125A breaker. But I say again, verify the cord and wiring before you do that.

Birken

MoonRise
10-13-2006, 04:08 PM
Hey zap, you have a machine that has a nameplate current draw of 96-110 Amps at 230-200 Volts, and you are running it on a 60 Amp breaker. If you have the output turned up on the machine, you'll be easily popping the 60 Amp breaker! Especially if the power company or wire losses are dropping the voltage on the low side of 200V. Then the machine tries to draw more amps to make up for the lower voltage, and POP goes the breaker.

Size the breaker and the wire(s) to handle the current needed by the device. For continous duty, barring an exception clause, paragraph, or section within the NEC (National Electric Code) regarding welders, a breaker is supposed to be used at only 80% capacity. So a 20Amp breaker is supposed to be used with a machine that draws no more than 16Amps continous.

I'd say you need a 125Amp breaker minimum, with the appropriate wire for a 125Amp breaker, to avoid tripping the breaker 'falsely'. The breaker isn't really tripping falsely, it isn't sized correctly for the machine. I don't know the applicable NEC exceptions for high-amp circuits feeding welders, but the general lookup table I have here says you need to use a minimum #2 AWG wire rated for 90 degrees C to/from that 125 Amp breaker.

A 100Amp breaker will not really meet the machine's amp needs, at 200V input your machine will draw 110 Amps. Pop goes the breaker. I routinely saw incoming voltages less than 200 V on a nominal 230V line during the summer.

You need a minimum 125Amp breaker to not trip when the machine is running 'normally'. I'd suggest going to a 150Amp breaker and the appropriate wire (#1AWG rated 90 deg C, as a minimum) for the welder. Going larger on the wire would be OK, and would be needed if you use wire rated at less than 90 deg C ( 60 deg C wire needs to be 3/0 AWG for a 150 Amp circuit).

Again, I don't know or have the current NEC handy to check for welder exceptions on the wire sizes, but IMHO you really-really need a bigger breaker and the appropriate wires to feed your machine.

Birken Vogt
10-13-2006, 05:34 PM
Size the breaker and the wire(s) to handle the current needed by the device. For continous duty, barring an exception clause, paragraph, or section within the NEC (National Electric Code) regarding welders, a breaker is supposed to be used at only 80% capacity. So a 20Amp breaker is supposed to be used with a machine that draws no more than 16Amps continous.

I am not taking you to task here but I adressed this in the previous post. I have a 2002 NEC. Welder calcs are pretty simple. The 80% on the breaker only really applies for continuous draw and a 40% duty cycle welder is far from continuous...


I'd say you need a 125Amp breaker minimum, with the appropriate wire for a 125Amp breaker, to avoid tripping the breaker 'falsely'. The breaker isn't really tripping falsely, it isn't sized correctly for the machine. I don't know the applicable NEC exceptions for high-amp circuits feeding welders, but the general lookup table I have here says you need to use a minimum #2 AWG wire rated for 90 degrees C to/from that 125 Amp breaker.

He said he is on 240v so 96A rating. Per article 630 the wire is sized for the welder times the duty cycle correction factor which is .63. So the wire is sized for 61 amps. With SO cord that means 4ga, it sounds to me like he is probably running SO cord direct from the panel to the machine.


A 100Amp breaker will not really meet the machine's amp needs, at 200V input your machine will draw 110 Amps. Pop goes the breaker. I routinely saw incoming voltages less than 200 V on a nominal 230V line during the summer.

It is possible for the line to sag but it should not sag that bad.


You need a minimum 125Amp breaker to not trip when the machine is running 'normally'. I'd suggest going to a 150Amp breaker and the appropriate wire (#1AWG rated 90 deg C, as a minimum) for the welder. Going larger on the wire would be OK, and would be needed if you use wire rated at less than 90 deg C ( 60 deg C wire needs to be 3/0 AWG for a 150 Amp circuit).

He can use either a 100A, 110A, 125A, or 150A breaker assuming he has 4ga SO cord to the welder because the rating for the SO cord is 70A, so again per article 630 he can go double the rating plus up to the next standard breaker size.


Again, I don't know or have the current NEC handy to check for welder exceptions on the wire sizes, but IMHO you really-really need a bigger breaker and the appropriate wires to feed your machine.

I hope he has 4ga SO cord to that thing. That has got to be some heavy cord though. I have 10ga running one welder and that stuff is heavy enough. The other one has 12ga which is a lot more manageable. Both are on 50A breakers and within code as far as wire size goes.

Birken

MoonRise
10-13-2006, 06:00 PM
Well, the machine nameplate says 200V-110A, 230V-96A 1 phase 60 Hz (we'll skip the 460V since he's not running the machine on 460V).

Just this summer I routinely, the majority of the time, almost every day, saw incoming voltage from a supposed 230V line running at less than 200V. Routinely. Which means that the equipment tried to draw even more amps than it would have at a higher supply voltage.

To avoid 'nuisance' tripping of the breaker, size the breaker to handle the load. In this case I think he really-really needs that breaker to be greater than 110Amps, so the minimum breaker he needs is 125Amps. Then size the wire to/from the breaker to be appropriate for the breaker capacity and the current draw from the machine. The final hard-wired cord from the wall to the machine may have the NEC welder exemptions/recalculations for allowed sizing.

And yes, those big wires are heavy, awkward, expensive, and heavy.

But if the machine is running at high output, it will pull 110 Amps at 200 Volts. The circuit feeding the machine has to be up to the task.

Duty-cycle exemptions/allowances won't held the breaker tripping when the machine draws more amps than the breaker is rated for. The duty-cycle allowances/exemptions apply to wire sizing (to protect the wires in the walls, raceways, conduits, etc) allowing for wire cooling during the 'off' times.

Again, I think we both agree that he needs a much bigger breaker to feed that machine. NEC allowances don't matter there. NEC allowances may affect the sizing of the wiring, I'd rather have bigger wires.

MicroZone
10-13-2006, 06:05 PM
Does the breaker not reset? ( i think you're saying it does) If not, disconnect the power and see if it resets. If it does...there is a wire grounding. I know this is a simple troubleshooting step but most times people skip over the simple stuff and look for the hard answer. Just thought I would mention it. ;)

Find out what else is on that circuit. Something else could be tripping it with the added drain from the welder. Once the welder is on - boom, the circuit can't carry the load. Just a few idea'rs... :)

zapster
10-13-2006, 07:44 PM
Does the breaker not reset? ( i think you're saying it does) If not, disconnect the power and see if it resets. If it does...there is a wire grounding. I know this is a simple troubleshooting step but most times people skip over the simple stuff and look for the hard answer. Just thought I would mention it. ;)

Find out what else is on that circuit. Something else could be tripping it with the added drain from the welder. Once the welder is on - boom, the circuit can't carry the load. Just a few idea'rs... :)


we have a 100 amp blanchard grinder on the same panel...
even when its not in use the breaker pops..

but today after the orig post i welded for 3 hrs with no problems.. until it tripped again and it was hot to the touch...

100 amp breaker here we come...

and by the way.. my brother did the wiring..licenced in mass. and he used only the best...because i said so...

but i wonder why he put a 60 amp breaker in there??

cant ask him now...he's flying around somewhere on a C-5 galaxy...


...zap!

Birken Vogt
10-13-2006, 08:09 PM
Well, the machine nameplate says 200V-110A, 230V-96A 1 phase 60 Hz (we'll skip the 460V since he's not running the machine on 460V).

Just this summer I routinely, the majority of the time, almost every day, saw incoming voltage from a supposed 230V line running at less than 200V. Routinely. Which means that the equipment tried to draw even more amps than it would have at a higher supply voltage.

Possibly but this is probably not an auto sensing Miller, therefore it has to be reconnected to take advantage of the lower voltage. If the voltage drops to 200v and it is connected for 240v more likely the output voltage will simply drop by the same amount.


To avoid 'nuisance' tripping of the breaker, size the breaker to handle the load. In this case I think he really-really needs that breaker to be greater than 110Amps, so the minimum breaker he needs is 125Amps. Then size the wire to/from the breaker to be appropriate for the breaker capacity and the current draw from the machine. The final hard-wired cord from the wall to the machine may have the NEC welder exemptions/recalculations for allowed sizing.

I agree the breaker needs to be much bigger than 60A but 125A is the largest you can commonly buy for a reasonable price. A 150A breaker, if available, will take up 4 places in the panel and cost hundreds of dollars. A 125A breaker should be plenty.

As far as wire size goes, 4ga is what the SO cord needs to be but the cable from the breaker panel to the junction box where it goes from hard cable to flex cable is dictated by Article 310 where it can be as small as #6 copper for 90*C wire. The SO cable gets a bigger wire gauge because its resistance to heat dissipation is higher and I believe it is 75*C. That is accounting for wire heating and not voltage drop of course. The wire heating calcs work if it is an inch or a mile. Voltage drop depends on length.


And yes, those big wires are heavy, awkward, expensive, and heavy.

But if the machine is running at high output, it will pull 110 Amps at 200 Volts. The circuit feeding the machine has to be up to the task.

Duty-cycle exemptions/allowances won't held the breaker tripping when the machine draws more amps than the breaker is rated for. The duty-cycle allowances/exemptions apply to wire sizing (to protect the wires in the walls, raceways, conduits, etc) allowing for wire cooling during the 'off' times.

Again, I think we both agree that he needs a much bigger breaker to feed that machine. NEC allowances don't matter there. NEC allowances may affect the sizing of the wiring, I'd rather have bigger wires.

I agree. Zap, you stated 100A but I would get a 125A because the price will not be much different, wire size is no different, and it will give you that much more headroom. There is no reason not to put in the largest breaker allowed really, within reasonable cost. If there is a line fault any size breaker allowed by the NEC will clear it safely. So I would go 125A.

Birken

slamdvw
10-14-2006, 05:41 AM
Zap... does your machine have a copy of the schematics in/on or around it? Not that it's real relevant to the discussion at hand, but could you scan it for me?
I think everyone agrees that the 60a is too small, but I'm more interested in HOW they're controling that machine. I have a hobart TR250... not a TIG box, but from the pics I've seen of yours, it's the same hobart yellow; so im guessing same age group.
( this question also stems from what you mentioned earlier "but like today i touch the footpedal and pop!" )

mucho gracias ( or however many thanks is spelled :) )

zapster
10-14-2006, 01:23 PM
Zap... does your machine have a copy of the schematics in/on or around it? Not that it's real relevant to the discussion at hand, but could you scan it for me?
I think everyone agrees that the 60a is too small, but I'm more interested in HOW they're controling that machine. I have a hobart TR250... not a TIG box, but from the pics I've seen of yours, it's the same hobart yellow; so im guessing same age group.
( this question also stems from what you mentioned earlier "but like today i touch the footpedal and pop!" )

mucho gracias ( or however many thanks is spelled :) )




slammed..
the date on the schematic is 1-11-74 its a hobart AH-250-HF
its glued on the inside of the top...
all i could do it try to get the best up close pics i could..
i dont know if they are any use to you but heres what i got..



5361

5362

5363

5364

5365


if i can get better ones monday i'll try if you need them..

thanks..

...zap!

northazman
10-14-2006, 09:42 PM
Well, the machine nameplate says 200V-110A, 230V-96A 1 phase 60 Hz (we'll skip the 460V since he's not running the machine on 460V).

Just this summer I routinely, the majority of the time, almost every day, saw incoming voltage from a supposed 230V line running at less than 200V. Routinely. Which means that the equipment tried to draw even more amps than it would have at a higher supply voltage.

It is possible that the voltage supplied by the power company is not 230V but 208V, especially if it is an older building or 3ph transformers.
I have this problem at my cabinet shop, which is in an old converted chicken ranch. The rated voltage is 208 and as such it doesn't take much for it to drop below 200V. I would guess that either way, if your supply from the panel to the welder is sized correctly, 4ga, a 100 amp breaker will suffice for a 40% cycle machine.

Another possibility is if you are cheating on the 40% and running the welder too hot. As it heats up, it is going to be less efficient and draw more amps.

Just my 2 cents
Reece

sail2u
10-15-2006, 04:18 AM
"if breaker was hot then i think of loose connection at breaker or wire loose
or just bad breaker
try new breaker, check for tightness at lugs"

If not yet done, please check for tightening at the wire lugs on the breaker before going on a spending spree.

We had the same problem with an older refrigerator erratically tripping the breaker, and after buying a new one which then tripped the breaker two weeks later, I found the wire was not tightened in the breaker -- 7 years after the house was built. The copper contracted when the garage got colder in fall.

just my $ .02

Birken Vogt
10-15-2006, 08:12 AM
Additionaly I forgot to mention, if the finely stranded wire from the SO cord is going directly into the breaker or panel, where it connects under the set screws (the stripped area) needs to be wrapped with a thin copper strip. The set screw should not be pressing directly on the fine wire strands. As stated a poor connection can cause heating as well.

Birken

Sandy
10-15-2006, 12:37 PM
Well, in a long standing and existing shop I'd say if the supply was anything other than conventional 120/240 you'd have discovered it before now. You would have had issues with previous installations.

Just a wild shot here but if this is an intermittent thing I'd look around at other things that might be going on at the same time one time but not the next. Might very well be a slightly under sized breaker, but something is causing it to trip one time and not the next.

Old installations can tend get unbalanced legs on rare occassion. Put this in, take that out, move this and that around. One leg pulling way more than another only at certain times. Old cruddy high resistance (impedance) joints, things like that.

Like I said, just a shot in the dark.

Rojodiablo
10-15-2006, 11:04 PM
It is possible that the voltage supplied by the power company is not 230V but 208V, especially if it is an older building or 3ph transformers.
I have this problem at my cabinet shop, which is in an old converted chicken ranch. The rated voltage is 208 and as such it doesn't take much for it to drop below 200V. I would guess that either way, if your supply from the panel to the welder is sized correctly, 4ga, a 100 amp breaker will suffice for a 40% cycle machine.

Another possibility is if you are cheating on the 40% and running the welder too hot. As it heats up, it is going to be less efficient and draw more amps.

Just my 2 cents
Reece
Zap, I am guessing this is your problem. I have a customer with a large building in Irvine, Ca. We went through like 3 A/C compressors in short order, and blew fuses left and right. I mistakenly thought we had power pulses going over-voltage. Morrow Meadows tech came out to help( Original Electrical contractor) and we found many super hot fuses on the roof, and several super hot breakers using thermal image camera....NEAT TOOL!!! Tested incoming voltage on both sides of regulator in the bldg transformer. Voltage went from 225 high.... supposed to be 240, to a low of 190VAC. This was making all the A/C units run SLOWER, and HOTTER. Plus, we saw major amp draw on all the units in question. Had to upsize several fuse panels to make due, and eventually Edison had to boost the electic flow from the transformer on the street to the bldg. My best guess, go up to 80A or 100A breaker, and check actual running voltage.

zapster
10-16-2006, 07:58 AM
thanks for all the responses guys..:cool2:

my brother the electrican will be here this morning..

we'll let you all know what we find out

...zap!

MicroZone
10-16-2006, 10:17 AM
Well...what did he find out? :)

zapster
10-16-2006, 10:46 AM
Well...what did he find out? :)


he's not here yet :sleeping:


...zap!

MicroZone
10-16-2006, 10:53 AM
Hahaha...call him and get his butt over there...we need to see your welds!

slamdvw
10-17-2006, 09:30 AM
hehe, I, myself was interested in the outcome... Zap: thanks for the pictures. I was interested in how the footpedal controlled the output, But seen a note on a pic to see a different diagram (which, im guessing is where the information was at ) Thanks again!

zapster
10-17-2006, 01:36 PM
UPDATE
my brother is here now..
he's changing the wiring from the breaker panel to the machine with some 150 amp wire..
100 amp breaker is waiting to get installed...

he said he went with a 60 amp breaker because the switch inside (where the wires go to) says its only rated 75 amps..

he thinks that was changed..

so when we get it running again i'm gonna run it flat out ..
we'll see if the switch inside likes it..

if not we'll change that too...

...zap!

MoonRise
10-17-2006, 01:55 PM
Ummm, Zap, remember that a chain is only as strong as its -weakest- link.

Your welder needs 96-110 amps (depending on the actual voltage getting to the machine), so the breaker, wires, and any switches or disconnects in the circuit need to be able to handle that as well.

Before, you had the machine trying to pull 100A let's say, but the breaker tripped at 60A. The (previously unmentioned) switch rated at 75A never exceeded its rated capacity.

If you don't run the machine at high-power, you won't have any problems (most likely). But do you want to have an electrical fire or have the machine be down (yet again) because the switch fried?

Do it once, do it right. Or you have to end up going back and doing it all over again. IMHO.

This has nothing to do with duty cycle on the welder, or wire sizing NEC exemptions for welding usage, or anything like that.

The machine needs 96-110A, to me that means you need a breaker that can supply at least that much current. The wiring and the switch need to be able to handle that much current as well.

You already have the electrician changing the wire and the breaker, change the switch/disconnect as well.

zapster
10-17-2006, 02:54 PM
Ok
we changed out the breaker..wires and switch..
i just did some "full throttle" welding A.C + D.C.

my brother says we're good to go now.. he had the meter on for the current draw..
says it never went over 80 amps...:cool2:

i'll keep an eye on it for a few days...

...zap!

MicroZone
10-17-2006, 02:57 PM
Sounds like that 60A breaker was getting a work out !

zapster
10-17-2006, 05:29 PM
Sounds like that 60A breaker was getting a work out !



:laugh: now its R.I.P.:waving:

...zap!

zapster
10-17-2006, 06:01 PM
and another thing..
thank you to all that gave me some input..:waving:

i'm no electrican:nono:

but i told my brother what some of you have stated and he said "tell me something i dont know"

i wanted to slap him but he'd beat the crap outta me..:laugh:

again thanks for the input..i actually learned something...like call on the pros when the $hi+ hits the fan...:realmad:

...zap!

codearc
10-21-2006, 03:45 PM
Had a problem like this with a machine a few years ago everyone thought that the day shift was sabotage it as the night shift had no problems at all it turned out that during the day the electricity supply was dirty with to many spikes due to eveyone on the estate using alot of current at peak times we put in a transformer to the main incoming supply it cost a fortune but it fixed the problem