From Newsgroup: sci.engr.joining.welding

Hey gang, I read this thread in hopes of finding the cure to my issue (which is similar). Got a Craftsman (Century) from 1992. First time in years IrCOve used it and IrCOve noticed the wire feed is slow AND weak. I can literally stop the wire feed roller with my fingers (and reasonable pressure) on full speed. IrCOve replace the gun, liner, and everything recently because the old one was just too stiff. I also did so in hopes it would solve the feed issuerCa nope.

IrCOve tested the motor on a 12v battery directly and can see that it and the gearbox are working fine - torque and speed. It was hauling ass and I couldnrCOt stop it with the same pressure as before. I spoke to someone at Lincoln (who now owns Century) and was told the board is likely not putting out the amps the motor needs for proper torque. I just bought the board, but donrCOt want to throw parts at it. I know something isnrCOt putting out the right amount of juice and IrCOm trying to figure out where itrCOs NOT coming from. Does this make sense to anyone else? I know things get old and stop working, but like the others, IrCOm not familiar with circuitry and and reluctant to just throw parts at it. I love this welder and really want it to work.

Thanks in advance for the knowledge.

-Jason from Denver.
--
For full context, visit https://www.polytechforum.com/welding/mig-wire-speed-control-problems-9075-.htm

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From Newsgroup: sci.engr.joining.welding

"Thesykboy" wrote in message news:175ed073079f0ac8$36$565070$c3d349d6@news.newsgroupdirect.com...

Hey gang, I read this thread in hopes of finding the cure to my issue
(which is similar). Got a Craftsman (Century) from 1992. First time in years I|ore4raove used it and I|ore4raove noticed the wire feed is slow AND weak. I can
literally stop the wire feed roller with my fingers (and reasonable
pressure) on full speed. I|ore4raove replace the gun, liner, and everything recently because the old one was just too stiff. I also did so in hopes it would solve the feed issue|ore4-a nope.

I|ore4raove tested the motor on a 12v battery directly and can see that it and the gearbox are working fine - torque and speed. It was hauling ass and I couldn|ore4raot stop it with the same pressure as before. I spoke to someone at
Lincoln (who now owns Century) and was told the board is likely not putting out the amps the motor needs for proper torque. I just bought the board, but don|ore4raot want to throw parts at it. I know something isn|ore4raot putting out the
right amount of juice and I|ore4raom trying to figure out where it|ore4raos NOT coming
from. Does this make sense to anyone else? I know things get old and stop working, but like the others, I|ore4raom not familiar with circuitry and and reluctant to just throw parts at it. I love this welder and really want it
to work.

Thanks in advance for the knowledge.

-Jason from Denver.

---------------------

Posted to sci.engr.joining.welding

The schematic for a Century Powermate 70 shows two apparently selenium rectifiers, a speed control pot and the torch switch in the wire feed motor drive. Any of them could be the problem.
-jsw

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From Newsgroup: sci.engr.joining.welding

"Jim Wilkins" <muratlanne@gmail.com> writes:

"Thesykboy" wrote in message news:175ed073079f0ac8$36$565070$c3d349d6@news.newsgroupdirect.com...

Hey gang, I read this thread in hopes of finding the cure to my issue
(which is similar). Got a Craftsman (Century) from 1992. First time in
years I|ore4raove used it and I|ore4raove noticed the wire feed is slow AND weak. I can literally stop the wire feed roller with my fingers (and reasonable pressure) on full speed. I|ore4raove replace the gun, liner, and everything recently because the old one was just too stiff. I also did
so in hopes it would solve the feed issue|ore4-a nope.

I|ore4raove tested the motor on a 12v battery directly and can see that it and the gearbox are working fine - torque and speed. It was hauling
ass and I couldn|ore4raot stop it with the same pressure as before. I spoke to someone at Lincoln (who now owns Century) and was told the board is
likely not putting out the amps the motor needs for proper torque. I
just bought the board, but don|ore4raot want to throw parts at it. I know something isn|ore4raot putting out the right amount of juice and I|ore4raom trying to figure out where it|ore4raos NOT coming from. Does this make
sense to anyone else? I know things get old and stop working, but like
the others, I|ore4raom not familiar with circuitry and and reluctant to
just throw parts at it. I love this welder and really want it to work.

Thanks in advance for the knowledge.

-Jason from Denver.

---------------------

Posted to sci.engr.joining.welding

The schematic for a Century Powermate 70 shows two apparently selenium rectifiers, a speed control pot and the torch switch in the wire feed
motor drive. Any of them could be the problem.
-jsw

A wider overall point:

With a MIG / GMAW welder, you deliberately set the drive rolls so they
will skid if the wire jams.
You set the pressure so the wire will feed, but any more resistance
than regular feed and the rolls slip on the wire.
That's the reason for the springs on the toggles mechanism for the
drive rolls.
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From Newsgroup: sci.engr.joining.welding

The problem is, there doesnrCOt seem to be enough amps to the feed motor to power it with the torque it needs to move the wire. IrCOve run the wire through 2 different liners and the resistance in the feed is the same. So IrCOm guessing the motor has to have a bit of torque to feed the wire.

Last night I tested amps where the leads come from the board to the motor. When the pot is set at 2, it reads .26 amps. When I keep cranking it up to 6, it hits .30 amps, and at 8rCa. same .30 amps. IrCOve looked at other motors online to get a baseline of how many amps that motor should need to do its job. Even the cheap ones on Amazon are doing .90, so IrCOm thinking the amps coming from the board are way too low. I found a company that sells a new OE board with pot and voltage dials on it for a decent price. I donrCOt want to just throw parts at it, but in my research so far, everything points to what is sending amps the the motorrCa the board.

Sound about right?
--
For full context, visit https://www.polytechforum.com/welding/mig-wire-speed-control-problems-9075-.htm

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From Newsgroup: sci.engr.joining.welding

"Thesykboy" wrote in message news:175f24e35dcf3418$1$3685597$13d399db@news.newsgroupdirect.com...

The problem is, there doesn|ore4raot seem to be enough amps to the feed motor to
power it with the torque it needs to move the wire. I|ore4raove run the wire through 2 different liners and the resistance in the feed is the same. So I|ore4raom guessing the motor has to have a bit of torque to feed the wire.

Last night I tested amps where the leads come from the board to the motor. When the pot is set at 2, it reads .26 amps. When I keep cranking it up to
6, it hits .30 amps, and at 8|ore4-a. same .30 amps. I|ore4raove looked at other
motors online to get a baseline of how many amps that motor should need to
do its job. Even the cheap ones on Amazon are doing .90, so I|ore4raom thinking
the amps coming from the board are way too low. I found a company that sells
a new OE board with pot and voltage dials on it for a decent price. I don|ore4raot want to just throw parts at it, but in my research so far, everything points to what is sending amps the the motor|ore4-a the board.

Sound about right?

------------------------------

A partly open bridge rectifier diode will give you the no-load voltage but
not the full current. Half-wave rectification is obvious if you have an oscilloscope. It might show up as a large voltage difference between when
the motor is connected and disconnected.

If you can find an electrical schematic for it I might be able to suggest other tests to locate the fault.

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