Oxford 180A single phase

[Luggsey]

I'm in the process of trying to rebuild one.
Can anyone tell me if the 180A single phase will power up off a 13A plug top or do they pull the fuse?
I'm obviously not trying to weld on a 13A plug top but would like to know from another owner if its possible to simply swith it on on a 13A fuse?
I checked the windings and insulation resistance which are all good and disconnected the inductor but it still pulls the fuse?

 

[Mikes]

Used to have a Oxford 185 which would weld alright on a 13 Amp supply for 2.5 rods but the fuse would go if I wound it up for 3.2 rods. The transformer losses are very small when just idling without load so you must have another fault to cause the fuse to blow.

 

[zzr1200]

Oil cooled welder or buzz box???

 

[Luggsey]

Oil cooled welder or buzz box???

Oil cooled but water cooled looking at the oil!

 

[Luggsey]

I can't think of anything else to try except its on the end of a 50m 1.5mm extension lead and that may cause a big volt drop on power up? It's difficult to get it closer to the house and some bugger nicked my 50m 2.5mm extension lead!

 

[qwakers]

Well yes, that would do it.

 

[not done it yet]

I think I used to fully turn down my welder to get it to start sensibly. Not an Oxford. It used to ‘drain the mains’ on initial switch-on.

 

[Mikes]

If you've got water in with the oil, it sits at the base of the tank and when it reaches a high enough level will short-out a component which is the lowest on the transformer (think it's a choke or something similar). Only real option is to drain the tank and try and separate the oil and water before trying again. Although the volt drop on your 1.5 mm2 cable will be excessive, it should not cause the fuse to blow when not under welding load.

 

[fnlvder]

Is this the welder from another post where you measured the primary windings and found 0.5ohms?

Itll be drawing about 500 amps.
The insulation on the windings is knackered

 

[Luggsey]

If you've got water in with the oil, it sits at the base of the tank and when it reaches a high enough level will short-out a component which is the lowest on the transformer (think it's a choke or something similar). Only real option is to drain the tank and try and separate the oil and water before trying again. Although the volt drop on your 1.5 mm2 cable will be excessive, it should not cause the fuse to blow when not under welding load.

I drained the oil and took in out on the bench, it was watery oil so may have damaged something?
Next weekend after it has dried out some more I'll try it closer to the house and update thisthread.

 

[Luggsey]

Is this the welder from another post where you measured the primary windings and found 0.5ohms?

Itll be drawing about 500 amps.
The insulation on the windings is knackered

I haven't checked it again since disconnecting the inductor so I will check it again next weekend.
I have no idea what the windings resistance 'should' be but I don't think a direct ohms law calculation works on a transformer? I will try and find out though.

Just looked and the quick formula shows 1km of 2.5mm2 copper wire has a resistance of 7.6 ohms.
I don't know the exact dimensions of the winding but it won't have much resistance.

 

[Barking Mat]

If it's like mine, you can wire it single phase, as said the power you'll get out of it will depend on the size of the power supply, available, but in lower settings it will work, great machine, I love mine.

 

[Luggsey]

If it's like mine, you can wire it single phase, as said the power you'll get out of it will depend on the size of the power supply, available, but in lower settings it will work, great machine, I love mine.

I have two of the 180A models and the one I'm working on is only single phase, the one with knackered secondary windings was like yours with single or three phase.
I hope I can save one of them!
I would consider rewinding them but the original windings are extremely tight and put together with wedges, I doubt I could hand wind neatly enough to make it all fit again.

 

[eddie49]

Post #7 of this thread has some examples of welder transformer primary coil resistance:

Sealey 180 supermig v3

My uncle has asked me to look at his Sealey 180 V3 but it looks like someone has been in there playing as some of the wiring looks (from the supplied schematic from sealey) to have been messed around with. One quick question, there is a sort of ferrite ring bolted through the base with red and...

www.mig-welding.co.uk

It concerns a 200 Amp Eland MIG welder, but should give a rough idea of what to expect ( e.g. 0.3 Ohms ).
As you said, using a digital Ohmmeter running off a 9v battery to measure the resistance of an inductive component doesn't translate via Ohms law into an AC mains current draw. If it did, then my "10 Ohm" VAX vacuum cleaner would pull 24 Amps !

 

[Barking Mat]

I have two of the 180A models and the one I'm working on is only single phase, the one with knackered secondary windings was like yours with single or three phase.
I hope I can save one of them!
I would consider rewinding them but the original windings are extremely tight and put together with wedges, I doubt I could hand wind neatly enough to make it all fit again.

Bet there's loads of you tube vids on how to do it.

But, yes, I agree, doing it properly, right, first time ideally.

Keep us posted.

 

[Luggsey]

Bet there's loads of you tube vids on how to do it.

But, yes, I agree, doing it properly, right, first time ideally.

Keep us posted.

I watched a great one a while back of what looks like an Indian yard workshop building transformers for welders similar to an Oxford one. They use steel plates in the transfer, the Oxford is brass, I think they use aluminium on the secondary as well!
I could do this but it takes sooooo much time I don't have unfortunately.
Now if I was retired.......

 

[Barking Mat]

I watched a great one a while back of what looks like an Indian yard workshop building transformers for welders similar to an Oxford one. They use steel plates in the transfer, the Oxford is brass, I think they use aluminium on the secondary as well!
I could do this but it takes sooooo much time I don't have unfortunately.
Now if I was retired.......

Yeah, it's a time issue, just another job..

 

[8ob]

Oil cooled but water cooled looking at the oil!

A lot of oils are hygroscopic, could this be partly responsible for the fuse popping

Bob

 

[Turbo]

Things with a great big transformer like an oil cooled welder will often pop a fuse or MCB the first time you switch them on. 110-240v yellow transformer boxes do it as well. I had a Pickhill that did it every time but once I reset the MCB it would happily run all day without tripping again. Its something to do with inrush current when you switch it on. It can be helped by setting the welder to a low output setting before switching on.

 

[Cobbler]

Ive got an old buzz box arc welder on the shelf that always took out the breaker first time you switched it on. Fine from then on. I really must get rid of it sometime, just collecting dust, anyone want it?