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therrera
02-01-2010, 01:08 AM
Hello all, (again)

Well, I upgraded my stick welder to this Hobart tr250hf a few days ago. When I test it, the person selling it said that it needed to have a higher amperage circuit feeding it as whenever he used the remote rheostat, it blew the breaker. All I did was see that it turned on and the guy's word that it welded fine except for the problem with the circuit.

So I buy it, get it home, plug it in and blow the breaker (mine is a 50amp). I had done a little research on line about this model and problems blowing the breaker and found out that several welders had to upgrade their circuit to 70 and / or 100 amps. So I did the same.

I just finished it yesterday (adding a 100 amp sub-panel). When I plugged the hobart in, it blew when I turned it on when I had it in DC straight or reverse, but turned on when in AC mode. It would blow the breaker when in AC mode about one out of five times.

It seems to have some kind of short that happens when it is in any DC polarity. If in AC, it turns on. However even then, it won't give me a hot arc and barely sputters.

Anyone have any ideas on this? I feel foolish for getting it on such superficial inspection and am reluctant to try and take it back especially because it came outfitted with a new torch and has a beefy water cooling system and remote and almost a full argon bottle plus flow meter. I paid $500 for her.

I went through a long saga repairing a Millermatic 250 with help from members on this board and don't look forward to doing it all over again with this machine, but I will if it is repairable and within my means as I have been needing a good TIG machine so I can lay off the gas drive welder that I used for this type of work.

Any help is appreciated.

Thanks,

Tony

Cruizer
02-01-2010, 03:31 PM
You have a fizzled diode (shorted)

therrera
02-01-2010, 05:57 PM
Hello Cruizer,

Is this a solder in replacement type of fix? Do I need to order a diagram for this machine to identify the diodes? When they short, will they discolor and thus readily identifiable? Will there be a bank of them and should they all be replaced at the same time, etc.? What do you think?

Thanks for the information.


Tony

therrera
02-06-2010, 05:53 AM
Hello all,

I received some advice from Billy regarding how to spot a blown diode. He basically said that the small ones would have the ends blown off and large ones would need to be tested by my meter in diode test mode.

I am waiting for the wiring diagram for it but in the meantime I will see if I can spot the obvious.

Will let you know what happens.

Tony

Billy
02-06-2010, 06:12 AM
Hello all,

I received some advice from Billy regarding how to spot a blown diode. He basically said that the small ones would have the ends blown off and large ones would need to be tested by my meter in diode test mode.

I am waiting for the wiring diagram for it but in the meantime I will see if I can spot the obvious.

Will let you know what happens.

Tony

Either way you will have to test them all, if only 1 is shorted or open it is best to replace that side. As they would have had a whack as well and may fail in a week or 6 months or whatever.

Rectifiers with the smaller type press in diodes are being used a lot more these days and the "tail" also acts as a fuse which will blow and basically taking it out of circuit.

Rectifier diodes will go short and trip your breaker.But as they short normally they will go open circuit in a rapid amount of time though. So if you start welding again and it does not trip the breaker but you have reduced power sure as eggs that is what has happened.

therrera
02-07-2010, 02:01 PM
Hi Billy,

I took out the diodes yesterday and tested them with a digital meter that has a diode test function. The spec calls for these to have between .5 and .8 volts passing through them from anode to cathode.

The meter put them over .5 and under .6 volts. They pass current only one direction. They would seem to be ok. However I think I read a few days ago that diodes cannot be effectively tested in a static fashion like this. I don't remember the procedure that was recommended as I was not at that point yet.

I located replacements on line for about $25 each. Do you think it would be best to replace them (there are two) just to eliminate these as a point of failure?

Attached are pictures of them.

Thanks,

Tony

transit
02-07-2010, 02:40 PM
On page 3, the diagram shows the relationship of current and voltage. The KNEE is the voltage across the diode when it is conducting current to a load.

Another way to test the diodes is to use the Ohm meter function.
Connect the meter leads to the diode. In one direction the resistance will be low, about 100 Ohms, reverse the leads and the resistance will be high, near infinity.
The diodes appear to be good with the results you’re getting.

Another test; with the diodes out of the circuit and all the wires to the diodes safely tucked in, not shorted to anything. Power on the unit in DC mode and see if the breaker pops? If the breaker pops with the diodes out, you have a short some where else. Now you need to find it.:confused:


http://www.electronics-tutorials.ws/diode/diode_3.html

therrera
02-08-2010, 01:40 AM
Hello all,

I took out the diodes and tested the welder without them installed. It behaved identically as before I took them out. When in DC straight or reverse polarity it blows the breaker in less than a heartbeat as soon as I hit the "on" button.

If in AC mode, it fires up without incident. I turned it off and on three times in AC mode without any ill effect.

This means that I have a short somewhere before the current gets to the diodes.

Anyone have some thoughts?


Thanks,

Tony

therrera
02-08-2010, 12:38 PM
Hello all, again,

On another board it was suggested I test the voltage at the plug to make sure it was wired correctly. I understand the idea behind the advice, which is to eliminate the obvious stuff first.

I tested for correct voltage when the sub panel was first installed. I also checked that the welder was setup for 230 volts as it has a set of changeable jumpers inside for various voltage settings. They are set correctly according to the diagram on the inside lid. In addition they are explicitly marked so it would be difficult to misswire the welder.

Finally, I have used this plug for running a MIG machine and plasma cutter without any trouble.

I did notice that when I powered it on, for less than a split second that it took to kick out the breaker, the fan started to turn. In AC mode, it ran without kicking the breaker off.

I wonder if the way to go about this is to isolate the various components and turn the machine on after disconnecting one component at a time. For example following the diode connections back, I could disconnect the next device in line, turn on the machine and see at which point it stops tripping the breaker.

This technique was taught to me here, in this forum, when I had to repair a damaged MIllermatic 250 welder. I had to eliminate that a short was coming from one of the transformers, so I disconnected the rectifier unit from the circuit, turned it on and was able to isolate where the short was coming from. It was the rectifier.

I am not a welder repair guy by any means, but with help (and logic) I was able to repair that one.

I will report how this goes.

Thanks,

Tony

therrera
02-08-2010, 09:35 PM
Hello all,

I received the manual from Hobart today and looking through the diagrams I saw the other two diodes that are in the machine. It never occurred to me to look underneath the assemblies, only on the surface. Sure enough the other two negative diodes were tucked on the opposite side (underneath) of some aluminum plates that are part of the rectifier assembly(?).

In any case, I got them out and see that they are numbered different than the first ones I pulled out. The manual refers to them as positive and negative diodes.

I insulated the leads going to them and turned on the machine and it stayed on, leading me to conclude that in fact it was the diodes all along. I had just not been thorough enough to catch it.

This is bringing back my experience getting the MIllermatic fixed. The diodes are the functional equivalent of the SCR's in the Miller's rectifier unit. In fact the manual for the scr's referred two types, stud mounted and hockey puck types. So now I am working with stud mounted ones.

They are available here for $22.69each:

Negative diodes:

http://www.galco.com/scripts/cgiip.exe/wa/wcat/itemdtl.r?listtype=&pnum=402832-3-NBR

Positive diodes:

http://www.galco.com/scripts/cgiip.exe/wa/wcat/catalog.htm?searchbox=402833-3

I will order them and fire her up as soon as I get them.\

Thanks,

Tony

Billy
02-10-2010, 08:44 AM
Hi Tony
Usually the negative ones will go in a MIG rectifier. After looking at the pics of the 2 diodes, there had to be more than that in there. Glad you have it sorted.
Cheers

zapster
02-15-2010, 10:30 PM
I have a whole machine I will give you for parts..No pedal..
AC don't work and the HI Freq. is shot..
It don't blow 100 amp breakers on start up though..


But you gotta come and get it..

...zap!

therrera
02-15-2010, 11:57 PM
Hi Zapster,

that's a generous offer. Where are you located? Please let me know and I may be able to do just that.

Thanks,

Tony

PS: I just got the diodes in today but will not be able to install them until tomorrow night as I am on a hot job that has to get done first. My family and I have a bad habit, we like to eat.

zapster
02-16-2010, 01:37 PM
I'm in Mass..

That's quite a drive from you..

...zap!

therrera
02-16-2010, 02:39 PM
Well,

I guess that won't work. A future generation will "beam" there and "beam" the stuff back.

Thanks,

Tony

therrera
02-18-2010, 12:05 AM
Update:

Hello all,

I installed the diodes just a few minutes ago and the machine works fine. Thanks to those in the know for your help. I now have a functioning stick machine. I have yet to test the high frequency.

Now the issue is that if the remote is plugged in, it has no amperage and the arc barely sputters.

Is this fixable or do I need to replace the remote? I have a miller foot remote. Could it be modified to work with this?

Anyone have thoughts on this?


Thanks,

Tony

therrera
02-18-2010, 03:44 AM
Hello all,

I did a little more troubleshooting on the problem with the remote. it turns out that the remote is just fine. I put an ohm meter on it, located a pair of pins that measured resistance with the movement of the pedal and watched the meter go from zero to 25 ohms more and less.

I opened up the foot control and it was squeaky clean and the contacts nice and shiny. So I did an experiment and plugged it back in to see if set to local mode the foot control had any effect on the welder.

My findings are:

The foot control works fine with the machine in local mode. In remote, it blows the breaker, every time. This was in DC reverse polarity. (DC is now working)

My initial conclusion is that the switch is shorted out and is "stuck" in remote mode when it is supposed to be in local mode. I conclude this because it blows the breaker each time it is pressed when in remote mode.

In local mode it operates the current fine and the high frequency as well.

In its present condition, I can remove the foot control when stick welding or scratch start tig welding.

Or I can connect the foot control and operate it and the high frequency with the pedal, leaving the switch in local mode and ignoring the remote position as it will blow the breaker. Not a bad compromise and it will work.

However, I would like to fix it. Is it safe to assume that the switch is bad or is there other circuitry that could account for this behavior? Would this switch be an off the shelf item? It looks to be a simple toggle switch. I haven't taken it out, but on the panel that's what it seems like.

Anyone?

Thanks,

Tony

therrera
02-19-2010, 03:11 AM
Hello all,

Well I started assembling the welder putting the sheet metal back on after replacing the diodes. During the process I tested the water cooler to see if it worked OK. I had just filled it up with filtered water.

This welder has a110 volt plug in front for the water cooler that turns on when the machine is tuned on and the remote switch set in remote mode. I discovered that when the water cooler was plugged into the receptacle on the front panel and I turned the welder on, it blew the breaker. When I unplugged the water cooler from the front panel, the welder stayed on.

This tells me that there is a short of some type in that plug or a circuit that connects to the water cooler receptacle. Since the plug is energized upon turning the machine on and I think when the remote foot control is pressed, it runs into a dead short.

Can receptacles short out? If so, could this be at the bottom of the dead short occurring whenver I turn the machine on and the remote is plugged in?

Thanks for any leads

Tony

DSW
02-19-2010, 08:14 AM
While I couldn't answer any of the other questions , this one I can help with.:)

Yes normal 110v receptacles can short out and go bad. I've seen it frequently with old ones when the plastic gets brittle. That should be an easy fix most likely compared to the others, as long as the machine uses a standard receptacle.

You should be able to remove the receptacle and have either 2 or 3 wires. A black (hot), a white (neutral) and possibly a green or bare copper wire ground (they may use the welder chassis as ground instead). At worst, remove the receptacle, remove and cap the wires, and retest. That should eliminate the receptacle as an issue.

therrera
02-19-2010, 01:19 PM
Hi DSW,

thanks for the tips. I will work on this today and hope by the end of the day I can at least determine it its the 110 volt outlet or not. If so, then its easy enough. If not, then I need to go down stream to see where the short is coming from.

If I disconnect the plug and turn on the machine I may get a false reading I think because the short may not be at the plug, but in another part of the circuit. It is only apparent at the plug when the short is initiated via the device being plugged in.

I will disconnect the plug wires and put a continuity meter in the plugs to see what happens. If no short, I will see it right away. My initial concern is if the wires go to a circuit board.

If that is the case, would I snip the wire in question, plug the cooler in, turn the machine on and see if it shorts? This way I think I could isolate the component one section at a time.

I know this much so far:

1) the machine stick welds in both AC and DC perfectly.

2) the polarity switches work as does the fine amperage control and coarse amperage ranges (high, mid-range and low).

3) the high frequency works and the remote foot pedal does it's job of controlling amperage at the stinger. I haven't yet tested the tig torch, but its connected to the same power lug alongside the stinger lead. So I have no reason to believe it won't work short of an internal break in the power lead going to it.

4) The water cooler works by itself when put on a separate circuit.

5) When the remote is plugged into the machine, it works fine as long as the local/remote switch is NOT in the remote mode. I haven't yet tested whether or not it activates the gas solenoid as I don't hear the click of any solenoids being activated when testing it. I suspect it won't. We'll see.

6) When the remote is plugged in and the local/remote set to remote, the machines kicks the breaker instantly.

7) When I have the water cooler plugged into the machine's 110 volt receptacle the machine won't work at all. I have to keep it unplugged to be able to weld.

I will report on what happens next.

Thanks,


Tony

zipzit
02-19-2010, 04:25 PM
Tony, Private Message sent... --zip.

therrera
02-20-2010, 12:59 AM
Hello all,

Well, it gets more interesting. I discovered that even though the remote foot pedal worked in local mode, the welder as a result kept the gas solenoid open effectively nuetralizing part of the reason for the remote which is to turn on these on demand. This way I would have to get a tig torch with a manual gas valve and be careful when I set it down as it would always be hot. The remote switch would however, give me control of the heat on demand.

To begin the testing, I disconnected the 110 volt outlet from the circuit and turned the machine on and lo and behold, it stayed on in both local and remote. Initially this seemed to be the problem. I didn't try to weld however, only see that everything came on, welder, water cooler and remote switch did not kick out the breaker when in remote mode. I could switch between local and remote and operate the foot pedal with no ill effect.

I then tested to see if the short was further into the circuit so I reconnected the outlet and traced the wires to the next device down the line from the outlet and it was a thermostat on the rectifier unit where the diodes had been replaced. I disconnected the leads from it and turned the machine on and it also stayed on and everything seemed to work. I found that all the accessories worked ( remote, high frequency, water cooler, gas solenoid and post purge timer, etc.). The remote side worked as did the local side.

I also discovered that by having the thermostat disconnected, the welder only sputtered with the high frequency arc but had no amperage at the stinger or the tig torch (this time I tried to tig with it). I tried connecting the leads to the thermostat once again to see how it behaved when separated from the cooling fins it was attached to. The welder stayed on like before but again, had no welding current, only the high frequency spark.

So I reconnected it as it was and turned the machine on and it behaved the same way again. That is, it would trip the breaker when put in remote mode and weld fine in the local mode.

This time I tried all the accessories and that's when I found out that I can weld as it is, but there is no machine intervention. Everything is manual as the remote does not turn on the accessories. As mentioned before, the purge doesn't work, the torch is always hot.

It appears that there is definitely a short going on, I just have to find it. Anyone have any ideas how to proceed with this?

Thanks,

Tony

therrera
02-21-2010, 12:57 AM
Pictures didn't get uploaded on my last post.

Thanks,

Tony

Bluewelders
02-21-2010, 01:11 PM
Disconnecting the thermal cut out just cuts power to the circuits downstream.
Where does the blue wire go,did you find a schematic ?

zapster
02-21-2010, 03:52 PM
There should be a schematic under the top cover..

If not then I will post pics of mine..

...zap!

therrera
02-21-2010, 05:15 PM
HI Bluewelders,

thanks for the info. The blue wire goes to the contactor relay which explains why I can't hear it kick in when pressing the remote and the thermostat is disconnected (or the 110 volt outlet for that matter) since the circuit is broken when I do so.

From there it continues with an orange wire to the HF switch. See pics. The blue / white wire is visible in the foreground and leads to the contactor relay where it continues as an orange wire. The orange bundle is the back end of the HF switch looking at if from behind the front panel.

I ordered the manual from the Hobart web site (only available as a hard copy) and took scans of it. I don't think it will let me send them to the forum as they are too large.

If I scale them down to cut the size, they are too blurry when trying to read them. If you send me an email to therrera@compusos.com I can reply with copies of the pages I scanned for your review. If that's OK with you.

Thanks,

Tony

therrera
02-21-2010, 10:39 PM
Hi Zapster,

the schematic on the cover seems to focus on the correct jumper settings for the various power options (200. 230, 480 volts). However I ordered a user's guide and and schematics and scanned the wiring part of it into files.

One member suggested that I learn to read electrical diagrams and to understand the various components of electrical circuits. It is a good idea and I'm going to take up his suggestion. Sorry to be such a hassle about this stuff.

For my next welder project, I will try and see if I can use that knowledge to figure this stuff out. The next one in line actually is getting an old Miller WC-3 controller working again. It was matched with an old Airco Miget spool gun to work with my constant current gas drive machine. I tried using straight polarity with it to do flux core wire and must've burned something out as since then it refuses to pass power to the spoolgun. Later a Miller tech told me that they were not designed to operate in straight polarity. My bad. But thats another story.

An electrician friend is coming by next Thursday to see if he can help me figure this out and I can show him the diagrams.

However if anyone has an idea how to proceed, I am all ears.

Thanks,

Tony

therrera
02-24-2010, 06:40 PM
I am getting help via email and was asked to clarify the symptoms again.

So I went out and fired up the machine. Local mode AC + DC fine. Then I plugged in the remote foot switch in AC mode and it worked fine. Then I put her in DC reverse and straight polarity and IT WORKED FINE!

I don't get it! Last night I tested it once again and was poking around to see if I saw something smoking or sparking, etc. and a spark light up near the contactor relay. I didn't test more and called it a night.

Today I go out and it works! So, is it possible that the contactor was stuck in an open or closed position, creating a short condition when the remote was pressed? Could the spark I saw (and heard) have been it "freeing" itself up?

In any case. I don't know what to say. The machine is working fine now.

Thanks to everyone for your help and input. I have gotten a hold of a book understanding electronic circuits and have handy so I can read it when I find free time. I expect to at least be more knowledgeable about these things.

Thanks again,

Tony

therrera
02-25-2010, 12:52 AM
Hello all,

Ran into trouble again!!!!

The latest news is that after I put all the sheet metal back on her, fabricated some welding lead hooks and a hook for the tig torch and cable, carefully ran all the cable, water hoses and argon hoses and got her all read to start using her, she did it again.

When I turned it on, the breaker kicked off in the blink of an eye. At this point I think it is coming from the main power relay. That's where the sparking was coming from (that area anyway as it happened so fast) and it seems to me that's the only area that could throw such a large spark in a flash and then quiet down.

I think tomorrow I will take her apart again and this time take out the relay and check the contacts as you said.

The general rule of thumb is to look for the simple stuff first and rule it out. That would be one area I haven't gone through.

Thanks,

Tony

therrera
02-25-2010, 11:53 PM
Hi all,

I have a friend that is an electrician that was supposed to come and give me a hand. He stood me up today. I will ask him if he can bring an amp meter to test in idea given to me on another forum. It is to pull the cover off of the breaker panel (a 100 amp sub-panel) and see how many amps the welder draws on start up as a way of isolating the contactor relay. I will have to wait until he comes around probably after the weekend.

I haven't been able to get around to the welder today, but thought I would share an observation. I notice that when it is working fine, the main power relay literally "kicks" in and you can hear it "clack!". When it does this, it blows the breaker.

When something seems to be "Seated" in its place I don't hear the "clack" or "clunk" of the relay kicking in. During periods when it is working and I have tested various modes (DC straight, Reverse, AC, with remote, etc.) the welder is quiet. When it fails is when I hear the "clunk". every time. I didn't make the connection until just now.

So, does this say anything that may offer a clue as to what is happening? To repeat, when the welder is working I don't hear the contactor kicking, it just fires up, the fan whirs away (loud I might add), the remote does its job and everything and everyone is happy!!

When it blows the breaker it does the "clunk" thing every time, no exception. This also occurs this way: I turn the machine on, it quietly starts and the fan makes its noise. No "clunk". I step on the remote and "clunk!" the breaker blows.

Anyone?


Thanks,

Tony

therrera
03-03-2010, 05:27 AM
Hi all,

Well, here's the latest. I found two machines exactly like mine on Craigslist. One in Arizona and one in California. I called the guy in Arizona and asked power requirements and he told me he has it hooked up to a 100 amp breaker. The guy in California said he has it hooked up to a 50 amp breaker and has never tripped it.

This told me that 100 should be enough and that the problem had to be in the machine. I don't have a fluke amp meter, but armed with the circumstantial evidence to date (blows breaker without consistency-sometimes yes and others no, saw large arc that threw sparks coming from the vicinity of the power taps / power relay, is silent when it does work and noisy "clunk" when it doesn't-consistently) I decided to take the power relay apart and check the contacts.

Attached are the pictures of what I found. Now, I've seen worse in other types of devices. However is it possible also that the relay is not engaging with enough power to close the contacts and maybe allowing them to arc, thus drawing more amps, thus tripping the breaker?

The four shot together are the bottom contacts, the ones in the plastic housing are the top contacts. One is the front set and the other the back set.

Can they be dressed up and end of story? Or should I think in terms of replacing the whole assembly?

Do these contacts look like the culprit or as a result of the culprit? What do you think?

My next question is: Where do I start looking for this part?

Also attached is a picture of the relay part label.



Thanks for all your input,

Tony

Bluewelders
03-03-2010, 10:08 AM
I would try dressing the contacts until they were at least "some" better.
Try to get whatever you do even.
Contactors of that size are kind of expensive.http://www.furnas-contactors.com/_product_48490/42EF15AF_Furnas-Siemens_Contactor
If it acts better with the points cleaned up, I could see if I have one similar in my power control parts.

therrera
03-03-2010, 12:44 PM
Hi Bluewelders and all,

I was thinking if I could find one cheaper, I could just replace it outright owing to the fact that the contacts are pitted the way they are. I wanted to run this one I found at a surplus site. What do you think?

http://skycraftsurplus.com/24vaccoil30ampcontactselectricalcontactorrelay-1.aspx

Its $45 plus shipping, a 50% savings over a new one from regular sources.

Are contactors like Capacitors in that they can be rated for greater capacity, but not lower?

I am attaching pictures. The first one is the proposed replacement. It is a three pole, where as mine is a two pole. However you can see by the picture that my old one apparently is also made in a three pole variation. I could just remove the center contacts (or leave them). Think so?

These are the specs of the proposed replacement:

208 - 240 VAC

3 Pole, Single Throw, Normally Open 90 Amp FL 120 Amp RES Contacts.
Terminals Accept 1/4" Push-On Terminals, Lugs Accept 16AWG to 6AWG

Power Ratings:
240 Vac 90 Amp 30 HP
480 Vac 90 Amp 60 HP
600 Vac 90 Amp 60 HP

Furnas 42GE35AG106



My old contactor's specs:
2 Pole, single throw, normally open 60 amp FL
Terminals accept 1/4" push on terminals, lugs (look like the are 6awg)
240 vac 60 amp


I am going out on a service call and will not be back for several hours so I will check in when I return.

What do you think?


Thanks,

Tony

Bluewelders
03-03-2010, 04:09 PM
A larger contactor won't hurt anything, but I think the coil on yours is a 115-120v.

therrera
03-03-2010, 08:17 PM
Your right. I didn't make the connection between the coil voltage and the contact rating.

Tonight I will clean and install the contacts and see what happens.

Thanks,

Tony

therrera
03-10-2010, 03:44 PM
Hello all,

I am checking in because I just replaced the 100 amp breaker after dressing up the contacts in the power relay.

The report is that the machine seems to be working fine. I think the previous breaker (only a couple of weeks old) either was bad or went bad after so many trips. I estimate I tripped it at least 40 times while I was troubleshooting this machine. So far I have turned it on and off about a half a dozen times without tripping the breaker in DC remote mode (which would blow the breaker about 3 out of 4 times without doing anything) and pressing the remote which in the past was guaranteed to trip the breaker. So far, so good, cross my fingers and knock on wood.

I got the contacts smooth and shiny again using a medium then fine fingernail emery cloth board. They sell them at the CVS (or Walgreen's) for about $3.00 for about 2 dozen or so. They already come in a mixed pack of half medium and half fine emery boards.

It was the only way to get in to clean them as the relay contacts don't have a way to take them out that I can see. It took about two hours to do all four of them. Whew!!!!

I found a replacement relay for about $124.00 and decided that if dressing them worked, then I will order one to replace the repaired on with. Maybe I'll wait until it goes out again though. If that happens, then it confirms that the problem has to be coming from somewhere else as was suggested.

Here's my theory: The machine went from an industrial environment (a welding shop) to a home environment and plugged into a 30 amp electric dryer circuit which had a run of about 30 or 40 feet to the main panel. This caused the machine to not have enough start up power, only enough to activate the relay and cause an arc between the contacts and over time it would blow the breaker with more consistency at each start up or every other start up whatever the numbers were as the contacts deteriorated and demanded more amperage.

Over time, more arc, more pitting in a continuous cycle to the point where it failed altogether to start or only started in one mode, AC, just as when I first go her. As soon as the relay was activated by the remote, it kicked it out. That's how it was when I bought her. That's why I think it improved slightly when I changed out the 50 amp breaker for a 100 amp one. It got more amperage to get around the burned contacts for a while longer.

I have a few fabrication projects on the table waiting for this machine to get working. Today I will start testing "online" so to speak.

I hope this got it and taught me a few more lessons in the process.

Last question: If it does burn the contacts out again, I should suspect one of the transformers? Checking it, would I check for resistance or a short or both? If resistance how do I know what its supposed to be?

Thanks everyone for all your help. If it works fine during these projects I will assume I'm in the clear and check in by the middle of next week to give the final update and bring this thread to and end.

Thanks,

Tony

Bluewelders
03-10-2010, 04:30 PM
There really is no transformers except the main one and the saturable inductor.
One of them usually wouldn't just give problem sometimes, and if it did, it wouldn't be economical to replace .
The power to run the contactor comes from one leg of the 220v.
If the voltage was not high enough the contactor would start to close and the voltage would drop.
That would make it start to open and the inductors in the welder would make the points arc.
The point arcing would make an out of phase condition at the native resonance frequency of the circuit.
Lots of volts and amps doing all sorts of interesting things.
The breaker would also tend to arc and ruin the points inside it.

There are a few places on the internet that sell rebuild kits for some brands of relays, may be an option.
If you find a contactor that is the same as yours, but the coil voltage is wrong.
Some of the contactors have interchangeable coils.

zapster
03-10-2010, 07:38 PM
You want the one out of the Hobart I still have?
Pay shipping and it's yours..



...zap!

therrera
03-13-2010, 12:31 AM
Hello all,

Well, in some ways I'm back to where I started. I replaced the breaker with a fresh one and it started right up as I reported a few days ago. Then I go out to do some work and Wham! it blows the breaker again. It did so consistently every time I turned her on. I shut it down, somewhat frustrated at the results so far.

Then I go out today to show a friend who wanted to see what was happening with it and Wham!! it starts up without a hitch, remote connected and works fine with the pedal. However when I turned her off and turned her on again, it blows the breaker!!

I let her sit for about 5 minutes and then fire her up and it turns on as before without any problem. My friend asks me what the amperage requirements are: To make sure, I look at the plate and it shows that it wants 96 amps at 230 volts, 110 amps at 200 volts and 48 amps at 408 volts. It is hooked up to 230 volts and the power taps are correctly lined up for 230 volt operation inside the machine.

If I read this right, it means that at 100 amps I might be at the borderline with this machine. Does that sound right? I think I am going to the tool rental place and rent me one of those clamp on amp meters that remember the reading as was suggested some time back.

This seems to be the only way I can tell if the problem is under amperage (one feedback I got was to put a 125 amp breaker in the panel). This does go against the feedback I've received about this machine working fine on 50 amps and 100 amps.

I don't know what other explanation. I figure the machine would either work or it wouldn't. When it turns on I can weld with it fine and the remote works like a charm. I played with it one time when it worked for about 1/2 hour without incident. Does that sound like a welder with internal problems? Doesn't it seem to point to the lack of external power?

Question: Is it possible that the relay is not engaging strong enough (like a weak magnetic pull) and causing the relay to arc, over amping the breaker and starting to burn the contact points as was seen in the pictures?

Question: will the breaker kick out at 100 amps? Does it have some play that will allow it to absorb say 110amps momentarily or are they pretty accurate and without much give?

Question: I am inclined to replace the breaker box with a on / off throw handle type switch with a slow blow fuse rated at 100 plus amps. Would this setup work better?

Question: Is it possible that this particular machine drawing more amps at start up is normal for it? Kind of like a car that say has a slower starter than normal. Doesn't fit the specs, but came that way from the factory?

Question: I notice that when it is plugged in, there is a slight hum coming from the front of the machine near the on / off switch which goes away when it is unplugged. Anyone know why this thing is drawing power when it is supposedly off? Could that be a clue as to what may be happening?

Thanks for any help,

Tony

therrera
03-13-2010, 12:36 AM
Hi Zapster,

I would like to take you up on that offer. Please email me with the details of how to best get the money to you. Maybe PayPal? Or I could deposit straight into your bank account if its a nationwide bank?

My email is: therrera@compusos.com.

Thanks for the help. With that part I could at least eliminate this as a source of the problem (or so I hope).

Tony

zapster
03-13-2010, 01:02 PM
I'll pull the switch out Monday..

I also have some polarity switch contacts and some fuses that are kinda hard to get that I'll send also..

The fuses are located in front of the machine under the panel..

...zap!

4sfed
03-13-2010, 05:45 PM
Tony,

A friend has the same machine and has been running it on a 50 amp breaker for years.

Jim

zapster
03-13-2010, 05:59 PM
When it worked mine did not like a 60 amp breaker at all..
100 and all was well until I killed it.

...zap!

zapster
03-16-2010, 06:31 PM
Couple of pics of your "New" stuff...
Switch..
Specs..
Fuses and NEW polarity switch contacts..


Let me know..

47970

47971

47972

...zap!

therrera
03-30-2010, 01:55 AM
Hello all,

well I have been using the welder for several days now as a stick welder. I did a small stainless job for a client last week and used the tig setup but found that the remote still causes the breaker to blow. I have been stick welding a trailer for three days now almost continuously. It has worked fine. I even have it running off of a 30 amp RV extension cord about 25 feet long to boot!! It turns on and off flawlessly. When I hook up the remote and set the welder to remote, it shorts out and blows the breaker. It is definitely something to so with that sub circuit. Any ideas anyone?

I had to use the tig setup without the help of the remote and found out that it welds fine and the high frequency works well too. By the way I also found out that if the high frequency is not turned on (either as start only or continuous), the gas solenoid will not allow the argon through. I was hoping I could use a scratch start with the stainless, but no luck. So I had to have the gas running while I tig welded the stainless and set the hi freq to start only.

Something in the remote circuitry is causing an overload or short condition to blow the breaker. It is not the welder itself, it is one of the sub circuits. Any leads?

Thanks,

Tony

Bluewelders
03-30-2010, 03:49 PM
According to the schematic the switch (S2) that turns on the HF, also powers the gas valve (L4).
Did you need to add a switch to disable the gas valve or HF ?

therrera
03-30-2010, 08:53 PM
Hi Bluewelders,

do you think by being able to narrow it down to the remote circuit, it might help isolate where the problem is coming from? It almost seems like it can be narrowed down.

Any ideas?

Thanks,

Tony

Bluewelders
03-30-2010, 11:54 PM
Does it make any difference where R3, the current control pot is set when the remote is switched on ?

woi2ld
03-31-2010, 12:10 AM
r u guys workn on the gold one or tha blue one

therrera
03-31-2010, 12:46 AM
Hi woi2ld,

I am trying to get the gold one working. Thats the TR250-HF.

Bluewelders, I will check tomorrow and report back on that.

thanks,

Tony

therrera
04-05-2010, 06:25 AM
Hi all,

I just got back from out of town and have not had a chance to do anything with the welder after posting my last message six days ago.

Bluewelders, I will test the welder and moving the amperage fine control to see if there is any difference in how it behaves.

Thanks,

Tony

therrera
04-06-2010, 01:08 AM
Hello all,

I was asked by bluewelders to check and see if the remote kicks the breaker off regardless of the position of the fine amperage control. Here is my report.

I just went outside and tested if it made any difference the position of the fine amperage control. The coarse adjustment was set to medium (I think it is 45 to 155 amp range). I cranked it up all the way to the right (high end of the scale) and turned on the machine with the remote connected. It fired up fine. When I pressed the remote switch, it worked fine and I released and pressed it again several times to simulate actual use. The third or forth time, it kicked the breaker off. I reset the breaker.

Next I put the machine in high range and turned the fine amperage control up all the way and repeated the test. I reacted identically.

This means that the remote actually worked for a few on and off cycles. Its almost like something heats up and then shorts. I am thinking that the suggestion to swap out the Square D breaker with a Cutler Hammer one might be the way to go after all given that it is not behaving logically. I mean, its not like the welder "got sick" and now is feeling better. Some variable is causing it to behave somewhat erratically. If the remote were shorted, it would have kicked the breaker off on the first try and not after three or four. Am I right on this?

Thanks,

Tony

This is the latest so far.

Thanks,

Tony

Bluewelders
04-06-2010, 10:35 AM
The transformer would seem to be OK.
There are few parts of the welder that can handle the amperage to over load the breaker, without exploding.
I doubt that the remote itself would be able to carry over 100 amps, even for the short time it would take for a breaker to pop.
The main transformer and the reactor are about the only large things that can handle that sort of current , without obvious damage.
And that they have functioned sometimes would seem to indicate a problem other than physical damage.
An intermittent in the saturable reactor circuit would be a possibility
I suppose trying to isolate the areas of the circuit with the largest amp draw during the fault might help.
Do you have a peak capture type amp meter ?
.

farmall
04-06-2010, 07:03 PM
Never forget the usefulness of "swaptronics".

If you can get with Zapster to obtain as much as possible of the organ donor machine, flat rate shipping ain't bad.

Also, thanks for the informative thread.

therrera
04-07-2010, 07:20 PM
Hello all,

I have already gotten some spares from zapster. The machine was scrapped. No more parts to be had there.

One of the members from another board is coming over tomorrow with a recording amp meter to help me track down the source of the short.

I will report back what we find.

Thanks,

Tony

zapster
04-08-2010, 05:19 PM
I have already gotten some spares from zapster. The machine was scrapped. No more parts to be had there.



I had thought it was scrapped BUT I still have it...
It got put on the other end of the shop but it's still here for raping....

...zap!

therrera
04-08-2010, 05:54 PM
Hello everyone,

Well guess what???

A member from the Hobart forum came by with his Fluke meter and had me plug the machine straight into the receptacle instead of with the extension cord without the remote attached. It shorted right away the first time around. I believe he got a reading of 40 amps on one of the legs. I repeated the experiment and this time it turned on without incident several times.

Then he had me put on the remote and we tried it again several times. It shorted again after I stepped on the remote and again after several presses of the remote. He tested both legs coming into the machine repeatedly and the readings were: 47 amps on one leg and 33 amps on the other. If I understand this correctly, I am getting under a 50 draw on this machine consistently. This is well within spec for the breaker that is rated at 100 amps.

This should rule out a defect in the welder entirely. NO? He suggested I take the breaker back and get a replacement. However this is the second breaker I have tried from the same source (Home Depot) and leads me to conclude one of two possibilities, maybe both.

1) The Home Depot where I got these from received a bad lot of Square D breakers and I got two of them one after the other.

2) The report that Square D breakers trip under their ratings is correct and I should consider switching to another brand. The suggestion was to go with a Cutler and Hammer breaker which according to the report will plug in correctly into the Square D sub-panel.

Any thoughts about this?


Thanks,

Tony

therrera
04-08-2010, 10:54 PM
Hello all,

Here is the latest:

I am open to the fact that the uneven amperage reading may be tripping the breaker. Pandinus, (a member of this board) made a technical observation that bolstered my gut feeling that this may be what has been happening. ( put a posting in the electrical forum where he replied) I recently changed out the diodes as the initial responses to my request for help suggested that my machine was displaying classic blown diode syndrome. I replaced all four. It improved as I was able to stick weld occasionally, but the problem did not go away (blowing the breaker).

I cleaned the contacts on the main relay until they were shiny new (they were badly pitted) and that also helped. In fact after that, I was able to stick weld with it in local mode consistently for days at a time. I found that for some reason, plugging into a 30 amp extension cord enabled the welder to turn on everytime. That is how I was able to take on the trailer modification project using the DC reverse.

Well just less than an hour ago I went to Home Depot, got a refund for the first breaker that I tried (Square D, 100 amp) and traded for a Cutler and Hammer 100 amp breaker as bigb suggested (another member of this board). I turned it on and put it in remote mode and lo and behold it has been turning on and off with the remote pedal consistently for over 10 cycles. That is pressing and releasing the pedal ten times. The most I could get before was 4 cycles before it blew the breaker. When I finish this post I am going outside and trying out some aluminum for about a half hour and see how it holds up. I already expect it will do fine.

I had to modify the Square D panel slightly to accept the C&H breaker by breaking off a small tab on the knife connector where the breaker slides over when installing it. Without this modification, that little aluminum tab acts like a stop and prevents the C&H breaker from seating all the way down into place by about 5/16". That's all it took, it fit like a glove after that.

I am elated as now I can take on aluminum and stainless projects without resorting to my gas drive, driving my neighbors nuts in the process. However it is still in the back of my mind that the uneven leg amperage reading may mean that there is a problem brewing down the road. I hope not.

I want to thank everyone for taking the time and brain power to help me with this. If anyone thinks I may have a problem as I questioned before, please let me know what you think and how I can rule this out or take preventive measures. I am not electrically very adept beyond basics but I can follow instructions well.

I will make my report later about how it went.

Thanks,

Tony

therrera
04-09-2010, 03:12 AM
Hi all,

I went out back and grabbed some scrap 3/8" aluminum plate I had and fired up the welder and went to work making a fillet weld "t" joint. I cranked up the settings to the highest settings and went to town with it.

I tacked it and started laying down a nice bead using the remote to control my starts and stops. It went off without a hitch. It seems to be acting fine and my only complaint is that the machine is so noisy.

I have always tig welded with air cooled torches, having learned way back when using scratch start on pipe roots and graduating to using high frequency with an on and off switch mounted on the torch handle that I used for aluminum welding. I also used scratch start for years at a stainless fab shop I worked at making custom restaurant equipment.

I rarely over the years used a remote amperage control but did find it useful and easier to weld with. Hence my experience is with air cooled torched more than the water cooled ones. The water cooled torch that came with this welder looks small to me. It has a 3/32" tungsten and collet and I wonder if I can safely use it with a 1/8" collet and tungsten? Compared to the air cooled torches I have, it is about the size of a 125 amp air cooled torch.

Being water cooled, how many amps can one of these torches take? I didn't finish the weld on the 3/8" plate because I was afraid I might burn up the torch as I had to crank up the heat to get it to weld, but maybe it was all in my mind.

I know that pictures I've seen of water cooled torches the torch seems small for the amperage rating it has but this is because it is water cooled. No?

I am satisfied that it is welding well and all functions are operating smoothly. I am leaving the sheet metal off of the welder in case there are some suggestions or testing that I need to do regarding the uneven leg amperage draw. Otherwise, it is ready to button up and put into production.

Thanks for all ideas, opinions and help.


Tony

Bluewelders
04-09-2010, 09:12 AM
I would guess that the imbalance is caused by some sort of waveform oddity at start up.
Does your welder have the power factor correction capacitors ?

I have also used a clamp ammeter that on the low settings would read different amperes, depending on the direction of current flow.
Either way I would just run it like normal and keep an eye on it for a while.

zapster
04-09-2010, 10:26 AM
Being water cooled, how many amps can one of these torches take? I didn't finish the weld on the 3/8" plate because I was afraid I might burn up the torch as I had to crank up the heat to get it to weld, but maybe it was all in my mind.



You probably have a WP-20 or equivilant torch and it will take what your machine will put out no problem...:cool2:
You can use the 1/8" stuff if ya want..
I basically use 3/32" for everything...

Post some weld pics!

...zap!

therrera
04-09-2010, 12:29 PM
Hey bluewelders and zapster,

thanks for your help and ideas. How would I tell if the welder has power factor correction capacitors? Would it be in the diagram's parts list? Are these capacitors that can be installed after market? Is their function to even out imbalances?

I thought of 1/8" tungsten only because with air cooled torches, you have to graduate to a higher rated torch (i.e. bigger) and I instinctively used 1/8" for higher amperages. I've already burned up lower rated torches welding higher amperages on aluminum. The cup was glowing cherry red and I saw some smoke looking stuff coming from the area so I stopped welding last night. However the torch body itself was not hot. I thought it good to ask.

Finally, is the coolant in the cooler just plain water or should I use some kind of anti-freeze solution? I have it filled with regular tap water now.

I'll run some beads later today and post the results.

Thanks,

Tony

therrera
04-09-2010, 03:30 PM
Hello all,

here is a shot of the 3/8" practice coupon I was testing on last night. I finished it this morning. I welded about 1/2 hour straight, multiple passes without a hitch. I like it. I used a 1/8" tungsten because the 3/32" was splitting up on me from the heat.


Thanks all,


Tony

Bluewelders
04-09-2010, 04:33 PM
I could talk about leading and lagging current and real and apparent power and things but basically
The power factor capacitors are to make the welder more efficient and maybe to reduce some of the static they emit.
Zapster may have some on the welder he has, if yours doesn't.
They are shown as an option on the diagrams.
they look approximately like this.:http://www.grainger.com/Grainger/items/4UHA2?Pid=search
They should I think be on the back of the back panel,as near as I can read it.

therrera
04-10-2010, 02:04 AM
Hi Bluewelders,

I'll look for them. Zapster, what do you think? Do you have these installed on your welder?

Thanks,

Tony

zapster
04-10-2010, 10:05 AM
Hi Bluewelders,

I'll look for them. Zapster, what do you think? Do you have these installed on your welder?

Thanks,

Tony

I'll look around on Monday for them IF they are there at all..:confused:
Glad to see that it is at least working correctly now..

The weld looks OK by the time you got to the middle of the weld..
More pre-heat time and keep the tungston out of the puddle...


...zap!

juamangi
01-31-2012, 02:48 AM
There should be a schematic under the top cover..

If not then I will post pics of mine..

...zap!

Hi, I hope not to be blocked by the board administrator to hang on this blog, but recently bought a machine like this, for supporting a classmate.

I bought it without testing, we finally between colleagues, when I connect, the fan turns on normally but want to use it the current is not enough to burn the rod.

I want it repaired with the help of my classmates and I can not, because the husband has already spent the money he took for the machine.

The problem I have is that the diagram in the inner cabinet is not appreciated, the color faded over time and that probably had incorrect storage.
So taking advantage of the support they have given to this blog, I would ask your support to give me an image of the internal diagram of the welding and with this try to repair the machine.

Greetings from Morelia Michoacan Mexico

Ricardo:waving:

therrera
01-31-2012, 04:53 AM
Hello juamangi,

I sent you a private mail on this subject.

Ola juamangi,

te mande un coreo privado sobre este asunto.