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I am looking at a generator that is rated for 2600 watts, total current draw 25 amps. It is currently set up with two hot lines separately connecting to a duplex receptacle rated for 15 amps and together connected to a receptacle rated for 15 amps at 240 volts. The supply paths include an 11 amp thermal breaker before the receptacle.

May I connect both hot lines together and instead replace the receptacle and breakers with one rated for the total current rating of the generator head without damaging the generator head windings?

I will also link to a similar question asking if multiple paths from supply to ground increases the allowable current draw but I don't think this is a duplicate as the focus is whether or not it exceeds the rating of those windings in the generator head. I will link to an answer to another question that discusses this.

Am I drawing more current if I'm giving multiple paths from supply to ground? https://electronics.stackexchange.com/a/7776/131959 http://www.northerntool.com/shop/tools/product_21008_21008

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  • \$\begingroup\$ Honestly the primary reason for the links is to demonstrate I've researched the issue. \$\endgroup\$ – Caruni Melj Dec 3 '16 at 4:37
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The generator you have is called a split-phase generator It is actually a single phase generator) and it's very much like having a center tapped transformer for output: https://en.wikipedia.org/wiki/Split-phase_electric_power

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V1-N is 120 V @10.8 Amps
V2-N is 120 V @10.8 Amps

This gives about 2600 Watts total power.

OR..... V1-V2 is 240 V @ 10.8 Amps for a total power of about 2600 Watts.

OR.... Any combination of 110 V and 240 V current draws that do not exceed about 2600 Watts total.

So to answer your question the windings are rated at 10.8 Amps maximum ....but for a short time the generator can sustain a 2900 Watt peak, or 12 Amps through the winding. The limitation here is not actually the winding current limit but the magnetic regulation that will cause the output voltage to drop (and hence the current will drop).
You CANNOT connect together the two 110 V outputs since they are not in phase. It would be like joining together the two output wires of a center tapped transformer. In the transformer case you'd burn it up, but in the generator case the output voltage would collapse (though it may eventually damage your generator if you left that short in place).

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  • \$\begingroup\$ Thanks for the great answer Jack. I was primarily wanting to use this for a 90 amp welder that recommends a 20 amp outlet and a 1.5 peak horsepower shop vacuum. Are you indicating this simply will not work trivially? If so that's great to know as it means I can continue shopping for an appropriate generator. \$\endgroup\$ – Caruni Melj Dec 3 '16 at 5:38
  • \$\begingroup\$ Theoretically you could use a 240V->120V transformer and connect it to the 240V receptacle. That said, I don't know anything about the practicalities of using these sorts of generators. \$\endgroup\$ – immibis Dec 3 '16 at 5:49
  • \$\begingroup\$ Your 90 Amp welder will have a power rating on it I assume. The While you want to weld at 90 Amps the voltage will rise and fall (based on you reducing or increasing the distance to the weld pool). This increases or decreases the power being applied to the pool. weldcor.ca/public/ckfinder/userfiles/files/FIGURE%20S-7.png It's likely that you have a weld voltage of around 20-30 V so a total power of around 1800-2700 Watts maximum in the pool. Given this I'd suggest that your welder would work on your generator and likely won't hit maximum current. \$\endgroup\$ – Jack Creasey Dec 3 '16 at 5:52
  • \$\begingroup\$ The other factor in using a welder is that your welder is not rated for continuous duty. So you will be using it for only a few minutes then resting. You generator is rated at about 2600 Watts continuous duty. under these conditions it will not overheat as it might with a continuous load. And of course I'm assuming your welder is a 240 V unit in all this. \$\endgroup\$ – Jack Creasey Dec 3 '16 at 6:01
  • \$\begingroup\$ @immibis. Yup, that's a good thought, you could use a 240-110 V transformer, but it might prove an expensive way to do it (get the line current down). Seems much better to buy a 120/240 V welder. Many of these can deliver up to 200+ Amps, but you can use them at 90 Amps of course. \$\endgroup\$ – Jack Creasey Dec 3 '16 at 6:16

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