Generating enough to Arc

[Def110TDi]

Evening all,

Years ago I bought a Honda powered 100a welder generator, great wee machine, handy for working away from power as she will power a 4" grinder too (see pictures), I believe she is old as I've never seen another like it

Last yeah as I moved onto working on heavier jobs I bought a Thermal Arc 175se, can't fault the machine and it is nice for the extra capacity, I'll add the spec sheet in a picture too

The bother I'm finding is the little generator running a Murex 6013 2.5mm is I find it struggles unless the engine is doing max RPM so I was pondering whether a senci sc9000-11 generator would run my thermal arc or if I'm wasting my thinking time? Biggest rod the thermal arc is quoted for is a 4mm, unlikely I'll use it, normally 2.5 or 3.2's I work with.

Also has anyone had any experience with senci products, can't find a review anywhere?

 

[voipio]

No experience here of using a Senci, but the general concensus seems to be that a 10kVa generator should have sufficient capacity to run a welder up to around the 200A mark. The Arcmaster spec indicates a rating of 9.2kVa for stick welding at max current (175A) so will probably do it, just. It'll be happier at around the 100-125A mark.

 

[Bill Edwards]

Generally speaking I find the output that the generator can supply needs to be no less than 50% higher than the welder needs for a diesel, nearer double for a petrol as they struggle to keep momentum when striking up.
Generators and welders aren't the best mix unless you've plenty of power. Of course you'll get away with a little less power by not using the welder at the higher settings but it'll still be fairly demanding. Also I'm not very comfortable running inverter machines off small generators for fear of them going 'bang'.

Be aware that KVA and Kw are not the same unit. KVA gives a higher figure which sounds good for selling generators, I can't remember the ratio but 6kva is probably around 4.5-5 kw.

 

[Def110TDi]

No experience here of using a Senci, but the general concensus seems to be that a 10kVa generator should have sufficient capacity to run a welder up to around the 200A mark. The Arcmaster spec indicates a rating of 9.2kVa for stick welding at max current (175A) so will probably do it, just. It'll be happier at around the 100-125A mark.

Thanks for the reply, by your knowledge the model up would be better suited with its 9.4kva continuous output, all be it I would never be using the welder at max capacity

 

[Def110TDi]

Generally speaking I find the output that the generator can supply needs to be no less than 50% higher than the welder needs for a diesel, nearer double for a petrol as they struggle to keep momentum when striking up.
Generators and welders aren't the best mix unless you've plenty of power. Of course you'll get away with a little less power by not using the welder at the higher settings but it'll still be fairly demanding. Also I'm not very comfortable running inverter machines off small generators for fear of them going 'bang'.

Be aware that KVA and Kw are not the same unit. KVA gives a higher figure which sounds good for selling generators, I can't remember the ratio but 6kva is probably around 4.5-5 kw.

Thanks, I've found the model up from that and it will produce 9.4kva continuous output

 

[henry Kadzielski]

Generally speaking I find the output that the generator can supply needs to be no less than 50% higher than the welder needs for a diesel, nearer double for a petrol as they struggle to keep momentum when striking up.
Generators and welders aren't the best mix unless you've plenty of power. Of course you'll get away with a little less power by not using the welder at the higher settings but it'll still be fairly demanding. Also I'm not very comfortable running inverter machines off small generators for fear of them going 'bang'.

Be aware that KVA and Kw are not the same unit. KVA gives a higher figure which sounds good for selling generators, I can't remember the ratio but 6kva is probably around 4.5-5 kw.

The conversion factor is dependant on the power factor, normally .8.
So for example 6kva*.8= 4.8kw. If your operational voltage is 240vac then your available current is 20 amps. simple. Most manufactures have a generator rating requirement for their machines, be it for stick mig and tig. The problem with generators is two fold. Diesel generally have a greater revolving mass and better govenor control, means easier starting due to the stored kinetic energy, and the type of alternator fitted. Most small gensets have cheap alternators which do not have good overload capacity (starting capacity) so when you startup or strike an arc the voltage dipps as well as the frequency. This is why they suggest an oversize genset to compensate for these deficiencies. The newer invertor machines are much kinder to the supply and you can use smaller sets to do the same jobs. The transformer type machines basically operated as a capacitor and pull a higher inrush of current on arc up.
So for most operators it is much easier to get a larger genset off the shelf, than say to spec up an appropriate model that will do what you require.

 

[Bill Edwards]

The conversion factor is dependant on the power factor, normally .8.
So for example 6kva*.8= 4.8kw. If your operational voltage is 240vac then your available current is 20 amps. simple. Most manufactures have a generator rating requirement for their machines, be it for stick mig and tig. The problem with generators is two fold. Diesel generally have a greater revolving mass and better govenor control, means easier starting due to the stored kinetic energy, and the type of alternator fitted. Most small gensets have cheap alternators which do not have good overload capacity (starting capacity) so when you startup or strike an arc the voltage dipps as well as the frequency. This is why they suggest an oversize genset to compensate for these deficiencies. The newer invertor machines are much kinder to the supply and you can use smaller sets to do the same jobs. The transformer type machines basically operated as a capacitor and pull a higher inrush of current on arc up.
So for most operators it is much easier to get a larger genset off the shelf, than say to spec up an appropriate model that will do what you require.

I couldn't remember the factor but I was about right with my rough figures

 

[Rig Pig]

If you're looking for a larger engine driven stick set then @spencer 427 has a beast for sale.

 

[HughF]

Yes, buy the mighty midget that Spencer has for sale, it's a good price for a decent machine.