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Spot welder timer replacement question

surplusjohn

Diamond
Joined
Apr 11, 2002
Location
Syracuse, NY USA
We have a couple of old alphil, 30 Kia spot welders, foot powered, we use them for some 12 gage carbon steel, but mostly for 14 to 22 gage carbon and galvanized. Lately they have been making random cold welds. We went through and cleaned up contacts, and looked for loose connections. But are still getting the same results. I am thinking it is the meteor timers. A quick look indicates that the timer relies on a potentiometer and capacitor. So perhaps a easy component replacement will solve the problem. I have to look at that more carefully.
Alternately we replace the whole timer. Can anyone recommend a specific replacement?
Thanks
 
I have Miller Spot Weld Timer. No complaints.

P.S. I'm curious what time you set for the above mentioned sheet (12ga, 14ga, 22ga). How long are your electrodes?
 
Mike, I am not the operator but I do know that the several different guys working in fab are not approaching the settings in any set way. We have 3 spot welders, all foot pedal, which the old time foreman, now retired, preferred. These are organized into overlapping work cells, so each one gets used for a variety of work through out the day. We are also considering adding a modern spot welder plus a btm togl loc clinching machine that will be dedicated to light gage galvanized fittings. This will allow dedicating machines to specific tasks.
Anyways, I will look at the Miller as a retofit.
 
Your timers are likely using the power frequency as the method of timing.. Which is best since you want the same number of cycles rather than an arbitrary number of seconds... You can use either method, just a timer not based on cycles will be slightly less accurate on short durations.

I've done about a dozen retrofits on older manual welders, and you can use timer modules. The big thing is that you have to get a contractor that can actually handle the amps. And even then you will be replacing them fairly often if you are putting a fair amount of use.. In my retrofits the timer modules I'm using can't even switch the contactor directly. They instead throw a relay that throws the contactors..

In some of my more recent builds I have installed a small 220v light that is connected to the welding transformer, this really helps shorten trouble shooting.

I would think it likely that you have either a bad timer or a bad contactor.
 
My spot welder needs a new control also.

The amps setup is a very old switch arrangement, it just needs a good cleaning and a bit of TLC

To switch in the load, I plan to go with a pair of 100 amp rated solid state relays
here's an example
https://www.mouser.com/ProductDetail/Crydom/84134040?qs=sGAEpiMZZMtq49AUx5G371MJ5wFqztmfTomyi8Br/7s=

Then get a multifunction timer like this one:
AutomationDirect: multi-function digital counter/timer/tachometer, 100-240 VAC operating voltage (PN# CTT-AN-A120) | AutomationDirect

set it up to run from 0.05 to 5 seconds every time the foot pedal is pushed.
 
My spot welder needs a new control also.

The amps setup is a very old switch arrangement, it just needs a good cleaning and a bit of TLC

To switch in the load, I plan to go with a pair of 100 amp rated solid state relays
here's an example
https://www.mouser.com/ProductDetail/Crydom/84134040?qs=sGAEpiMZZMtq49AUx5G371MJ5wFqztmfTomyi8Br/7s=

Then get a multifunction timer like this one:
AutomationDirect: multi-function digital counter/timer/tachometer, 100-240 VAC operating voltage (PN# CTT-AN-A120) | AutomationDirect

set it up to run from 0.05 to 5 seconds every time the foot pedal is pushed.

I have something very similar on three of mine (soon to be five).

When I did mine I did dual timers, one does the weld timer and the other the post hold. When I push down on the electric foot pedal it trips a pneumatic solenoid which operates a small piston which closes the tongs (kept fairly tight together). Then when the welder is fully closed and provided the foot pedal is still held down, a pressure switch triggers a relay which locks in the solenoid and starts both timers, first timer starts the weld contactor and the second locks in the pressure switch relay.. When the timers run out the contactor turns off and the unit opens (unless the foot pedal is still held down).. The whole thing is a bit of a jumble of wiring but it works really well, and has been more reliable than the few that we made with PLCs. PLCs don't seem to like being next to big transformers, seems to mess with them.

Naturally the wiring is dictated more by how you use the machines.. But I do like redundant safeties, since I've had the misfortune of having one lock in the on position liquefying the part I was making.
 
I think it is fixed. I went over every connection, cleaned every contact, etc, no improvement. finally, I turned the potentiometer all the way up and down and returned it to the original setting, and it has been working well since then, knock on wood. so thanks for the info, everyone.
 
AutomationDirect: multi-function digital counter/timer/tachometer, 100-240 VAC operating voltage (PN# CTT-AN-A120) | AutomationDirect

thanks CSS. we ordered one of these. we cut the old timer out and manually touched the wires together and was able to get good welds. so 99% sure it is the old timer, I am keeping my fingers crossed that this solves the problem.
 








 
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