dose anyone have now how and abilaty to rewind my spot welder transformer,
or know were i might get a back door job done,
regards malcolm
spot welder transformer rewinding
Moderator: RichardW
Re: spot welder transformer rewinding
Unfortunately I do not have detailed knowledge, nor know where you could try, but a few observations.
On many transformers these days, the laminations are assembled by MIG welding. If so, repair will be near impossible.
The secondary open circuit voltage is usually about 2 volts, and for 2 volts, the 230v primary would have 115 turns. The wire is likely to be rectangular section, and possibly aluminium instead of copper.
Another possible construction would be copper or aluminium foil of the full window width, wound with paper or plastic insulation. It might be feasible to rewind this yourself if you could get the materials.
Fred
On many transformers these days, the laminations are assembled by MIG welding. If so, repair will be near impossible.
The secondary open circuit voltage is usually about 2 volts, and for 2 volts, the 230v primary would have 115 turns. The wire is likely to be rectangular section, and possibly aluminium instead of copper.
Another possible construction would be copper or aluminium foil of the full window width, wound with paper or plastic insulation. It might be feasible to rewind this yourself if you could get the materials.
Fred
Re: spot welder transformer rewinding
thanks for your reply Fred
but this is avery old hand held spot welder which has a seperate control box, the actual hand held part being the big heavy transformer,
possible 1930's or 40's
i belive it runs on 36V at 25A as thats what the lable on the big heavy switching gear inside the control box has on its lable,
regards malcolm
but this is avery old hand held spot welder which has a seperate control box, the actual hand held part being the big heavy transformer,
possible 1930's or 40's
i belive it runs on 36V at 25A as thats what the lable on the big heavy switching gear inside the control box has on its lable,
regards malcolm
Re: spot welder transformer rewinding
Are we talking about a resistance spot welder, where you clamp 2 steel thicknesses together with copper jaws, then it applies a very large current? In this case, the working voltage across the jaws is about a volt, but the current is several thousand amps. Since this means 10 to 20 kw from the mains (briefly), makers usually disguise this – eg “average power 3kw” so as to appear to be within a 13 amp rating. So the 36V at 25A could be misleading.
However, is it an arc spot welder, which would be more like the 36V? Also, does the control gear also have a large transformer? If it is a resistance welder, and the hand part input is about 36V, then the primary of the hand part would only have a small number of turns, but a very heavy winding. But the actual current would certainly be a lot more than 25A.
Can you post photographs to give some clues?
Fred
However, is it an arc spot welder, which would be more like the 36V? Also, does the control gear also have a large transformer? If it is a resistance welder, and the hand part input is about 36V, then the primary of the hand part would only have a small number of turns, but a very heavy winding. But the actual current would certainly be a lot more than 25A.
Can you post photographs to give some clues?
Fred
Re: spot welder transformer rewinding
it is a resistance spot welder and the control box has two small transformers and a huge device that look like a big relay with all the contacts exposed,
if you can pm me an email address i will try to ssend you some picys as i have probs send picys the the forum,
regards malcolm
if you can pm me an email address i will try to ssend you some picys as i have probs send picys the the forum,
regards malcolm