415V single phase

[dman]

I have inherited a welder (a WIA Weldarc 230) from my father-in-law and I think it uses a single-phase supply. Its got a round 3-phase type plug and the socket in his workshop says 400V. I don't have 3-phase currently connected.
I've done a search, and it seems I'm not the only non-sparky whos a bit hazy on multi-phase supplies.
What I'd like to know is do you have to have 3-phase installed to get the required 415V single phase? I'm thinking that you probably need to use 2 phases to get the necessary voltage - but I'd like to confirm.

[OBBob]

You can get converters (see link) but it doens't look cheap either way.

http://www.woodworkforums.ubeaut.com.au/showthread.php?t=37362

[dman]

Thanks obbob, but I don't necessarily want 3-phase power as supplied by these converters. The welder wants 415V single phase - so a converter would be overkill I think.

[pedro the swift]

To get 415v (if thats what the input to the welder is) you need at least two phases wired to your place.
I guess if you wanted to go the expensive route you could use a 240/415 v transformer but the cost would not be worth it and the current drain would mean larger size wiring on the 240 side most likely.
If you wanted 2 phases wired to your house you would have to talk to the power company any have suitable extra main cable, meter and circuit breaker cabled to your welder. I dont know what policy there is on 2 phases. maybe they only will install 3 phases and then only for special needs.
good luck

[bennylaird]

I think your barking up the wrong tree here, 415 is made up of 3 X 220(240)V phases than give the equivalent of 415.

The 3 pins on your plug are for each phase and not the same as 240 with active, neutral and earth.

Story is you will need 3 phase to drive it.

[Felder]

I think gregoryq (forum member) knows something about this....

I've sent him a PM and asked him to join in. :)

[Buzzer]

Hi dman,

I had a WIA welder similar, if not the same, as yours some years ago now.

I can faintly remember the welder I had, had connections inside the cover you could change for either single phase 240v or three phase 415v.

As far as I know, there is not 415v single phase.( I am not an electrican, but have a farm workshop with both 3 phase 415v, and single phase 240v supply.)

Cheers.

[bennylaird]

http://www.phasechanger.com/how_it_works.php

[pedro the swift]

Bennylarid,
You are correct in what you say re 3 phase, but I interpreted the question to be about a 415v single phase welder. They are about and it is possibly what he has.
The questioner needs to have close look at the name plate and that \sholud tell him exactly what supply it needs.

[spartan]

As other have said...unless your device says 3 phase, 415v. You could get away with 2 phase, however, its only used in certain applications...

Lighting on sporting fields comes to mind, and when people want phase separation in their homes.

The main reason (I believe) is that the cost of installing 2 phase would be of little difference to three phase, and its more practical to draw the requisite current over 3 phases rather than 2 (as implied by Benny).

The bottom line is you will need an electrician to install the three phase. They will then put in a 3 phase order for with your local electricity distributor who will then arrange three phase connection and meter. The electrician will then modify your circuits, including distributing the load of existing circuits across all three phases.

You will need a three phase circuit breaker - with a nifty label called 'workshop', and the cable and outlet run to the appropriate place.

I would estimate about $2000, inclusive of board upgrade and distributor fees...

[bennylaird]

http://www.phys.unsw.edu.au/~jw/power.html

[bennylaird]

I'm not familar with 2 phase devices but they would increase the power. Voltage would not be as high as the normal 440v.

I have not seen a 415V single phase supply on the normal grid but suspect it may be available in some workplaces derived from 440 3 phase.

[dman]

Thanks all for comments,
I've searched the net and managed to find an old manual for this welder. Turns out that it can be set at 240, 415 or 480 V (all single phase). So I should be able to use it without getting 3-phase installed.

However still a bit confused about the 415 & 480V settings - am I right in thinking you would need 2 or 3-phase connected to get to these voltages, but they would need to be combined in some way?
The welder has only 2 wires - so must be single phase?

All a bit academic now I know it can run at 240V - but would still be interested to know...

[b1ueshift]

Thanks all for comments,
I've searched the net and managed to find an old manual for this welder. Turns out that it can be set at 240, 415 or 480 V (all single phase). So I should be able to use it without getting 3-phase installed.

However still a bit confused about the 415 & 480V settings - am I right in thinking you would need 2 or 3-phase connected to get to these voltages, but they would need to be combined in some way?
The welder has only 2 wires - so must be single phase?

All a bit academic now I know it can run at 240V - but would still be interested to know...

I've not heard of a 480V machine before - I'm not sure how you would obtain that voltage in practice.

You are correct in that you need at least 2 phases available to get 415V. If you are interested in how phases work, it might take a while to explain. Mains electricity is AC (alternating current) which means the voltage on each phase goes up to +340 V then down to zero then down to -340 V then up to zero and repeats at 50 cycles per second. It is called 240V because that is the RMS (average) voltage. If you put one probe of a multimeter on neutral and the other on a phase, you would measure 240V. The voltage on each phase are different, but they arn't opposite, they are 120 degrees out of phase. What happens if you put a multimeter probe on one phase and the other probe on a different phase, you would measure 415V.

[Stringy]

An old Australian welder.

The welder you have has a bridge plate inside and should also have a wiring diagram pasted on the cover plate. This is electrician territory as it is the primary side of this welder, 240/415v.

By changing the bridging it will run off the following power supplies:

240v 32a you will not have an outlet for this but a new 32a circuit can be wired in by leco seperately for your welder, this will be the cheapest way to go. most stove/oven combo's run 240v/32a.

415v 20a this uses a single phase of the 415v.

480v 20a 240v/10a + 240v/10a sounds weird but what they did was run 2 seperate 240v circuits into the welder to make up the 20a draw. This scares me:eek: .

I own a CIG Transtig 180 which has the same system, it is unique to OZ, there are no benifits running the 415v.

Hope this helps, remember electricity is silent, invisible and deadly!

[dman]

Thanks Stringy,
It all makes more sense to me now - I just couldn't figure out the 480V thing!
I've got a separate circuit box in the shed - I'll get a sparky to put in a 32A circuit for this and do the back plane changeover to from 415V to 240V.

[cyberhonky]

although the question has been answered, i'll continue on. In a lot of industrial situations, many single phase (240v) machines (mig/tig/arc bandsaws etc) are wired to a 3 phase plug (using only 1 phase). Being metal trade/welding background (possibly the enemy to some here:p) it was common place at many factories, as it took the load off the single phase circuit, and didnt make the 3 phase circuit work hard at all.

I remember starting early in summer time to get the welding done before the heat, and even on 3 phase circuit you knew when others in the street were starting up their equipment, cause you had to up the juice on your machine to compensate.

As for getting 3 phase at your place, if you tell them its for a welding machine, they'll probably laugh before telling you the answer is 'no', so yeh, go with the voltage change;)

[chrisp]

To answer the original question, to have 415V single phase, you need two (240V) phases connected to your house (it's quite common).

The phases are 120 degrees apart so the maths is:

(240V at 0 degrees) + (240V at 120 degrees) = 415.7 V at 60 degrees

(You can draw it up as a triangle and treat it like a trigonometry problem.)

You don't need three phases for 415V equipment.

The 480V is typically for SWER (Single-Wire-Earth-Return) installations as used in remote areas (farms and such). There is only one phase supplied, but the pole transformer has a 480V secondary that is "centre-tapped" effectively giving two 240V phases that are 180 degrees apart. You can use a single-phase for the usual 240V gear and a 480V for the higher power gear (such as a welder).

I hope this helps.

Chris

[thatirwinfella]

the train of thought that some of you seem to be stuck in is that there are only two ways of getitng your voltage... 230v single phase of 415v three phase. the 230v is measured to neutral, which is [theoretically] at 0v at all times. that is from any phase, the red white or blue, not some mysterieous 4th pahse used only for 230volts.

415 volts three phase is largely used for motors where the difference between the phases is used to rotate the stator creating motion, but thats another story. the 415 volts in question here is measured across any two phases... red to white, red to blue, blue to white. there will be 415v across these.

thats where this 415v single phase is coming from... it's just like single phase, but rather than being down to neutral it is to another phase.

finally, if you were to measure voltage across three phases simultaneously it would be zero volts... which is where the neutral comes into it. This is also the star point of star wound motors/transformers. delta misses out and doesn't have a point of zero voltage, or 230volts.