size generator

[spaffmonkey]

evening all

me and a good buddy of mine have handed our jobs in to start our own small fabrication buisiness as we have been asked to do alot of mobile site work.

we will be doing mig, tig and arc welding and wonder if anyone knows what sort of kva we might require without going overboard as we still need it semi portable.
we have a 180amp inverter arc, 250amp invertor mig and a 220amp ac/dc tig on order.

cheers

 

[zzr1200]

If you've ordered a top end 220amp tig unit that runs on a 16amp blue plug , you'll get away with one of these, but you'll need to have the AVR unit built in as well to protect the inverter circuits.


http://www.sgs-engineering.com/gene...10000-super-economy-portable-petrol-generator

 

[spaffmonkey]

what does the AVR do ?

 

[addjunkie]

Regulates the generator speed to make sure you have the right output to satisfy the load requirments.

Automativ voltage regulator

 

[zzr1200]

Automatic voltage regulation, Gennys that rely on capacitors to control the voltage varies to much and can damage electronic PCB's.
The AVR circuits control a much tighter voltage range.

 

[spaffmonkey]

ah i see that makes scence now.

 

[spaffmonkey]

Ive run the invertor arc of a 6kva before but when i tried the mig the generator just kept overloading.

 

[zzr1200]

The power drain requirements on the generator totally depends on how much you spend on the welding units in the first place.

 

[addjunkie]

On the back of your mig will be a data plate with input current requirments. From that you can work out the load. Roughly kva required is about 80% of that

250 amp mig will be about 32 amps so probably 7 or 8 kva.

For site work should you not be using 110v tools....not sure but sure sparky types will be along to keep you right

 

[spaffmonkey]

ill check the mig in the morning. its the jasic 250

 

[addjunkie]

https://www.jasic.co.uk/mig250compact

This one ...states 10.8 kva

 

[spaffmonkey]

so really i need somthing around 12 kva.

it is a loverly welder to use. ive had it just over 2 years now and still love it. ive done alot of arc with it and have got a spool gun for it to.

cheers for your input guys

 

[zzr1200]

.http://www.sdmo.com/EN/Products/PPW/Portable-power-generators/Technic/TECHNIC-10000-E-AVR


http://www.sgs-engineering.com/generators/portable-petrol/hy12000le-petrol-generator

 

[Bill Edwards]

You normally need considerably more output from a generator than all the data plates suggest. 50% more tends to be a minimum in my experience of running welders off generators. So a welder requiring 8kw would need an absolute minimum of 12kw, 15 would be my choice if it was going to get regular, heavy use. Bear in mind that working things hard and at the limits won't extend their life, and good generators and AC tig's are not cheap.

Be aware that kw and kva are different measurements. I think it's 0.8kw= 1kva.
That means that generator suppliers tend to market in kva as it makes their units sound bigger, don't get caught out.

 

[henry Kadzielski]

Good morning gents.
Just to clarify AVR is as was stated previously 'automatic voltage control'. This is a electronic circuit board that controls the output voltage, as well as other functions, droop, max excitation to name a few. It DOES NOTHING regarding speed control. Unless you get a invertor variable speed generator, which in it's case the voltage control electronics control engine speed and voltage output. These units are generally small and you won't get the output required to run a welder. So we are talking about a fixed speed gensets, which are available in both diesel and petrol versions. The engine controls the speed and what you will be looking at is a 'A' class governed engine. This is then coupled to a alternator and the type of alternator for the voltage quality output is important. These alternators are available in either brushed or brushless, either or works well. What you are after is a, as close as possible a pure sine wave output irrespective of load. Another requirement is the overload rating. Some welders require a surge of current to get things going on startup. The genset you select needs to accomadate this inrush current. Generally new high end invertors are very good at limiting this inrush for the genset to cope. Hope this helps

 

[zzr1200]

For site work should you not be using 110v tools....not sure but sure sparky types will be along to keep you right

Depending on what job is being done on site, you can find direct mains 240volts on some sites although generally only to thing like small tig welders, some large electric scissor lifts and very rarely at times you can even find 3 phase extension leads running across sites to large machines.

Then of course you can now find the blue transformer (a 110 Volt to 240 Volt transformer) plugged into a 110 volt 10/15Kva site box with a lead running off across the wet floor........

 

[Rig Pig]

Don't be tempted by a Chinese toy if you're looking at making a living from it, spend a bit more on a proper industrial machines with a real AVR and governor that won't toast your welder or die on you when you need it. If you're just doing the occasional job away then maybe renting one when needed may be cheaper.

 

[zzr1200]

http://www.generators.co.uk/Product/0000003482/Technic_10000E_AVR_MODYS

 

[spaffmonkey]

That's excellent thank you.

Between us we have a good amount of tools and equipment to get us started but we are trying to get going on a 6k budget so the generator might be a rental item to start with until we fully up and running.
Our list to buy at the moment is
Ac/dc tig (on order German made)
Big compress suitable for air tools.
Plasma cutter
20ft shipping container. We are setting up in a local boatyard as they want welding done also but we need to get the container.

 

[slim_boy_fat]

@spaffmonkey Good luck in your new venture, mate.