Oxford bantam 180

[fieldmouse]

Hi guys,

i've been given an oxford bantam 180 amp stick welder and changed the old 415v for some robust 240v cable. I've wired it brown to 230v, blue to zero and earth to the centre terminals. However, it keeps blowing the 13a supply when i switch it on and before i even get near to welding. I know previous threads mention using a 16a supply but i don't want to go down that route until i'm sure the welder isn't a snotter.

Have i wired it wrong or is the supply inadequate, even on standby? If it's a duffer is there a way to test it using a multimeter?

Help!

Jas the 'mouse

 

[rtbcomp]

By blowing the 13A supply do you mean the fuse (or MCB) or the earth trip (rcd)?

 

[madkayaker]

take a photo of the terminals and data plate we can advise better then

 

[fieldmouse]

By blowing the 13A supply do you mean the fuse (or MCB) or the earth trip (rcd)?

The RCD is tripping at switch on, I'll take a piccy of the terminals and post it.

 

[rtbcomp]

Sounds like you've got the earth connection in the wrong place.

Can you check continuity between the earth pin on the plug and the chassis?

 

[madkayaker]

it is a RCD or a RCBO?

 

[fieldmouse]

Hi there,

i tried posting a pic but made a pig's ear of it so i'll describe what it looks like.

The terminal connectors look like the number five on a dice;

top right = 415v
top left = 380v
centre = earth (i think....)
bottom left = 230v
bottom right = 0

I've got brown live to 230v, the blue to 0 and the earth to centre.

I've performed continuity from the earth pin on the plug to the chassis and that's fine.

Does this sound ok?

 

[madkayaker]

OK try continuity between the 230v and 0V between each other and to the case

 

[fieldmouse]

Now then,

chassis to the centre terminal is zero ohms
230v terminal to chassis is infinity
zero terminal to chassis is infinity
230v terminal to zero terminal is zero ohms

I'd have thought the last one should've been infinity.

 

[madkayaker]

that's you problem which fuse is it blowing a RCD, MCB or Fuse?

 

[madkayaker]

what is the resistance between 230V and 0V

 

[Robotstar5]

that's you problem which fuse is it blowing a RCD, MCB or Fuse?

Why?, some equipment does have neutral strapped to earth

 

[madkayaker]

yep but if thats the case the RCD won't like it

 

[fieldmouse]

Hi Mad,

I've just adjusted my reply tp your previous question as i'd mad a typo.

As for my supply, its an RCD consumer unit.

I have access to a disused cooker supply, is it worth while connecting this to the welder?

 

[fieldmouse]

If the RCD is upset at an earth coupled neutral, what do I do with the blue supply wire?

 

[madkayaker]

as that makes a big big difference. There should be a low resistance between 230 and 0V it might just be a over load issue what size a supply are you using also what resolution did you have the tester on

 

[madkayaker]

RCD isn't the issue now

 

[fieldmouse]

MMM,

it's a standard 13A supply that trips on initial switch on.

I'm using a Fluke 73 digital multimeter stolen from my days in the merch.

chassis to the centre terminal is zero ohms
230v terminal to chassis is infinity
zero terminal to chassis is infinity
230v terminal to zero terminal is zero ohms

With that last reading I've basically got live and neutral shorted!

I must have the wires wrongly connected but I can't see where.

 

[madkayaker]

sound like you have connected right but that the winding insulation is shot. Is there a data plate telling you the KVA rateing

 

[fieldmouse]

Hi Mad,

just had a ganders at the plate and it says kva 5.

Wouldn't a rdc trip occur if neutral and live were shorted?

Jas

Ps: just pulled your file, kayak, climbing and welding. Kindred spirits..... tho I'm more open canoe