UK calc help

[john waters]

Hi its been a while since college and need some help with a calc.
I have been asked to put in a supply for a old spot welder ,The only info i have is
its 150 kva 2 phase .
I need help to calc amps

 

[telectrix]

so on 2 phase that's 75kva per phase (approx. assuming load shared equally). assuming 230V per phase, that gives you 75K/230 = 326A per phase. !!! bloody big cable for that beast. but i can't see any welder being 150KVA. someone must have misread. 15KVA seems closer to the mark, and even that's a lot.

 

[westward10]

Industrial spot welder can go up to 300kva.

 

[James]

It might be worth involving someone with experience in this field.

A load like that turning on and off can cause all sorts of issues in the property.
From electric noise affecting radio and computer systems to motors and lighting being affected.

Also it may well have a huge inrush current so protection of circuit will need to be considered carefully.

If the site has pfc it could play havoc with the controller for that.

 

[davesparks]

so on 2 phase that's 75kva per phase (approx. assuming load shared equally). assuming 230V per phase, that gives you 75K/230 = 326A per phase. !!! bloody big cable for that beast. but i can't see any welder being 150KVA. someone must have misread. 15KVA seems closer to the mark, and even that's a lot.

It's a spot welder, those things can get a lot bigger than 150KVA!
[automerge]1583399444[/automerge]

It might be worth involving someone with experience in this field.

A load like that turning on and off can cause all sorts of issues in the property.
From electric noise affecting radio and computer systems to motors and lighting being affected.

Also it may well have a huge inrush current so protection of circuit will need to be considered carefully.

If the site has pfc it could play havoc with the controller for that.

I know of one that was running on free electricity for about 6 months, the type of meter they had couldn't register the short pulses properly and so didn't record the power used.

 

[john waters]

pic of rating label if any help

 

[telectrix]

never seen 'em that bit, but then again, i don't do welding.

 

[Lucien Nunes]

It's single-phase 415 / 400V. It needs to be connected across two lines of a 3-phase supply to get 400V, hence the comment about it being '2-phase', but the unit itself is actually single-phase. Therefore 150k/400=375A. However, lower rated switchgear and circuits are often permissible because of the very short duty cycle.

As above, impulse loads can cause widespread disruption if not properly allowed for. The DNO have limits and requirements to ensure that they do not adversely affect other customers. Needs specialist advice before proceeding.