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Century wire feed motor


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01-14-18, 08:01 AM   #1 (permalink)  
Century wire feed motor

i sent in a post previously for a 1996 Century Model 117-037-903 that had a bad fan motor which i rep;laced with success. However when I went to use the welder a day or so ago, I could not advance the wire with the hand gun. (blew a house circuit breaker) I reset the breaker but if I hit the trigger now the wire feed motor (I think) buzzes loudly (does not advance the wire) I released the wire tensioner to see if the motor would even turn, and it wouldnt. I have THIS motor out now and would like to test it before ordering a new one. It appears to be A 24 VOLT DC motor rather than the AC type motor the like the fan was.
What is the best way to test this motor? I find it strange that I would lose two motors at the same time. What else could need replaceing in the circuit?

 
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01-14-18, 05:17 PM   #2 (permalink)  
Century Wire Feed Motor

I got the test procedure off Utube and it passed the test. I got it to run by itself with a 12 Volt DC power supply. I put it back into the mchine and hit the trigger on the wire feed gun. I got the same buzz sound, but determined that it came from a part beneath the wire feed motor. It is listed as a "reactor" part number 860-670-888. I have been unable to find one on web searches. Is this available anywhere you guys might know?

 
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01-14-18, 06:30 PM   #3 (permalink)  
A 24vdc motor fed with AC will make a 60hz chatter.

The schematic I'm looking at shows the wire feed motor connected directly to the control board. The reactor is a welding process transformer. It won't affect the wire feed.


~ Pete ~


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01-15-18, 10:41 AM   #4 (permalink)  
Century Wire Feed Motor

Well I was just going to where the noise was. but go figure... Before I read your latest post, I called the number on the original owners manual for customer service and was referred to Lincoln Electric, who must have bought out Century. Customer service there, verified your diagnosis (if it not being the "reactor" but possible diodes or a "triac" relay that is mounted on the Fan box (remember that I had a bad fan I had to pull out and could only remove by removing the box. which included removing diodes and the triac. SOOOO I probably put something back together wrongly, The rep from Lincoln told me I could call him back when it was more than 17 degrees farenheit in my garage, and he would assist me in trouble shooting. When it is above freezing, I will dig into it and post back.

Thanks for the replies!

 
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01-15-18, 02:16 PM   #5 (permalink)  
I see the diode plate. Doesn't show where it's mounted but it's not part of the power supply that runs the wire feed. There is a 24vac drive transformer that feeds the control board directly. That is converted on the control board to the DC voltages that run the wire feed and gas valve.


~ Pete ~

 
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01-15-18, 03:07 PM   #6 (permalink)  
Diode Plate

I can see it too, but Jim at Lincoln says that a bad diode or triac relay would
cause the overload which makes a loud buzz, and trips my breaker when I hit the trigger for the wire feed motor, not the reactor.
](although I would swear that the reactor is what is making the noise. Their number is 866236 0044 (select option 2) if you want to discuss it with Jim. None of this will make sense to me until I find something, or replace something that doesn't test on a meter like it is supposed to. Repaired a lot of stuff, but never a welder, If you two figure it out, post it back to me. It is too cold here for me to work unless I know exactly what to fix so I can get back inside fast!

 
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01-15-18, 03:22 PM   #7 (permalink)  
Ahhhhhhhhh....... you were assuming it was the wire feed. Ok..... it's most likely not.

When you squeeze the trigger.... multiple things happen. The gas valve opens, the wire feeds and the voltage for the spark is turned on. Yes.... looking at it that way.... it could be a diode or wiring problem and the wire feed is ok,

If the reactor transformer was feeding into shorted or miswired diodes.... there could be a problem.

It would be time to fire up the ohmmeter.


~ Pete ~

 
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01-15-18, 03:31 PM   #8 (permalink)  
Wire Feed

I originally did think it was the wire feed. Even took the motor apart. (thought the noise was coming from there, but it was underneath the wire feed assembly. I'm hoping that it is just one of the wires I disconnected to remove the fan box but I'm glad you and Jim are at least on the same page if not the exact paragraph!

Thanks!

 
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01-15-18, 03:33 PM   #9 (permalink)  
I'll come out and fix it but you gotta supply the transportation.


~ Pete ~

 
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01-15-18, 05:51 PM   #10 (permalink)  
Century Wire Feed

That is a tempting offer, but it will be easier for you if I fix it here, and give you the credit for it.

"There is no limit to how far you can go, or what you can achieve in life, if you don't care who gets credit for it" (Harry Truman)

 
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01-24-18, 09:50 AM   #11 (permalink)  
Century Wire Feed

I had a warm day here, so I got the welder case off exposing the innards again. I took out both diodes and they check out ok according to what i have seen. ( Ohm meter almost pins needle in RX1 with leads going one way, moves only slightly with leads hooked up in reverse) the small 4X2" panel mounted on the side of the fan box must be the Triac, but I have not called anyone yet about the procedure to test that. Anybody had one of these fail before?

 
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01-24-18, 10:02 PM   #12 (permalink)  
Triac ?
I don't see that listed in the schematic. I do see 4 lead component..... could that be it ?
Looks three white wires and a yellow wire to it.

Can you check the red and black receptacles to ground ?
I don't think there should be any short to ground on them.


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01-25-18, 08:57 AM   #13 (permalink)  
4 lead receptacle

On the schematic it might it is listed as a relay, in the parts list the corresponding code says it is a "triac- relay" There are 4 leads attached to it. two of them go up to the top of the fan case and attach to a small round disc (thermostat) held there by two sheet metal screws.
I will go out later and recheck where the other wires go exactly. "from the description I just gave you above, something is wrong. The two wires ( one yellow and one white) , both are not supposes to go to thermostat from the relay, just the yellow one is. on the schematic here in front of me. The white wire heads for the terminal board, on the schematic, but I don't believe the one that is actually there is long enough to do that. it is the same length as the yellow wire which just makes it to to the top of the fan box. Ill get back to you.,...


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01-25-18, 01:20 PM   #14 (permalink)  
Century Welder motor replacement

Ok, I checked the wires against the schematic and I found that the wire going to the thermostat mounted on top of the diode plate was on the correct terminals. The other wire was attached to that wire but went all the way back to the circuit board. All good there. HOWEVER (and I have to take the blame for this) there are two other terminals on the relay marked ONE and TWO . Both of these terminals had brown coated wires fastened to them. One went to the transformer and one went all the way to the main on-off switch.
These were switched. SOOOO now I guess the FIrst place to check is to see if I fried the relay. OHM meter is reading continuity between terminals 1 and 2. but I dont know if they are supposed to. There is no continuity between relay terminals 3 and 4
With everything back to where it is supposed to be. (I think) If I hit the trigger for the wire feed, it snaps the 50 breaker in the box on the garage wall RIGHT NOW (no buzz ,no nothing. (if I re set it , I can get the cooling fan to turn on again) Now Im stuck again.

 
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01-25-18, 03:58 PM   #15 (permalink)  
Century Welder motor replacement

I called Lincoln Customer Service. They had me take the Triac relay out of the circuit by disconnecting the brown wires that go to the switch and the transformer. This allowed me to test all the switches that engage the wire feed motor, the gas valve and other controls, which I could hear all engage when I hit the button in the weld gun. They then told me to connect the two brown wires together (with tape) which would also bypass the triac relay but should activate a power transfer so you can weld. Hooking thee two together shut down the machine when I turned on the MAIN power switch. i did not even have to toggle the gun.

They have asked me to try to run it with just one diode hooked up to try and see if one is bad even if it tested ok with an Ohm meter. I plan to do that tomorrow. There are one or two capacitors in this circuit, Any know how to properly test these?

 
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01-26-18, 08:52 AM   #16 (permalink)  
Testing a Triac

No one wants to tell me how to test the "triac" which to me is the smoking gun to the solution of this problem. the wires to it were the only mistake I KNOW I made in reassembly after repairing the motor.....

 
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01-26-18, 04:51 PM   #17 (permalink)  
Is the triac the four lead part ? I don't see it on my schematic.
A triac is only a three legged semiconductor.
Did you check the ports like I asked ?


~ Pete ~

 
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01-27-18, 10:05 AM   #18 (permalink)  
Century Wire Feed Motor

You were asking me to check the ports. I'm not sure if what I checked is what you mean, but I checked the main black leads that go from the fan box to the main transformer (and one red one) for shorts and continuity. result: no shorts and complete continuity. (The guy from Lincoln was walking me thru this)

Yes the triac relay that mounts to the fan box has four leads. two brown wires going from terminals 1 and 2, and a yellow and a white wire that go from terminals 3 and 4.

I googled " how to test a triac" yesterday and got a response from Electronic Circuits and Diagrams-Electronic Projects and Design - An Authentic Resource on Electronics which walks me thru the tests of the Triac I have. I will get after that and post my test results. If it comes up ok, it will be good (triacs are expensive!) If bad, at least I can get one and keep going!

The guy from Lincoln says that even a positive test on the diodes can be misleading. He wants me to disconnect one diode at a time and see what happens when I hit the gun. If the triac is ok, I guess that is what I will do next

 
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01-27-18, 01:36 PM   #19 (permalink)  
Trac Testing

The triac failed the test BUT the test instructions said "this test is not applicable to triacs with high gate voltage and current for triggering " If the number one on the triac itself is MT1 per the test, it says 240V AC for "output" Terminals 3 and 4 have a note on them as being "INPUT" 3.5-26V If the gate is on this side of the triac, I tested it in the wrong place. I could use more help here!

 
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01-27-18, 02:36 PM   #20 (permalink)  
Been crunched for time lately. I'll be back to see if I can help further.


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01-27-18, 03:59 PM   #21 (permalink)  
Diodes

With nothing more important to do, I went ahead and put the triac back in the machine, and removed one of the diodes. I started the machine and triggered the weld gun. It worked! I have the diode on the table in front of me, but it tests ok with a multimeter. Other forums and posts indicate that this is normal. The diode can still be bad. I only have two, (both the same part number) so unless you say to do something else first, I guess I will order both of them. Polarity shouldn't matter if they are the same diode, right?

 
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01-27-18, 07:16 PM   #22 (permalink)  
If it's a factory part it will be marked. Diodes are a DC component and are polarity sensitive. It may work with one diode but that will only output half the current. Try the same test by swapping diodes.

What meter are you using for testing and does it have a semiconductor setting on it. Looks like the picture of a diode symbol.

When testing diodes..... probes in one direction should show no continuity. Reverse the probes and you should measure several hundred ohms.


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01-28-18, 09:22 AM   #23 (permalink)  
My Ohm Meter was probably used by Edison. It does not have the semi conductor setting. The diodes in the part list are just one part number for both, and I do not see any polarity indicators on the one in front of me. Probe test indicates it is ok (at least with this meter) So swapping diodes, if I get the same result, (machine still works with half Power) or do you want me to but them both back in on opposite sides?

 
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01-28-18, 11:42 AM   #24 (permalink)  
Ok.... in looking over what I have for a schematic.
Terminal 1 - to power switch
Terminal 2 to large transformer
Terminals 3 and 4 to the control board.

That part cannot cause a short circuit..... or a short to cause the breaker to trip. That part takes low voltage and uses that to control the high voltage. I can't call it a triac as a triac is a three legged device. If that part directly shorted on it's own.... the welder would be at full amperage and running.

The diodes are bolted on a common metal plate/heatsink..... correct ?
Hmm.... something just hit me.... I think that metal plate needs to be insulated from the metal chassis/case. Check that out.


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01-31-18, 09:14 AM   #25 (permalink)  
Diodes

The diode checks kind of like you say with the setting at RX1 one way no continuity, the other way 10 Ohms of resisistance At the Rx1K setting I get SOME continuity testing one direction, and get about 4 ohms resistance going the other way. I will head to the garage and cross check these with the other diode and see if the plate is not touching anything. It would seem to me that if it was, It would be shorting out and blowing the breaker now when I hit the trigger, as all I did was remove the one diode. I will let you know!

(I get it about the triac being a 3 legged component, it just happens to be what Century calls this relay in their book. It is wired exactly as you described)

 
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01-31-18, 09:40 PM   #26 (permalink)  
I get SOME continuity testing one direction, and get about 4 ohms resistance going the other way.
That is a bad diode. I'd change them both.


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02-01-18, 08:55 AM   #27 (permalink)  
Diode Testing

Everything points in that direction, I'll make the order out today. you will here me cheering all the way to New Jersey when the welder lights up!

Thanks!

 
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02-05-18, 09:39 PM   #28 (permalink)  
Century Wire Feed motor

I replaced the diodes today and got the same result. If I trigger the gun, I trip the main 50 amp breaker in the wall box. If I remove the diode on the left side of the Fan box (as you look at it from the back of the welder) I can trigger the gun without tripping the breaker. Could one of the capacitors be doing this?

 
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