Power Inverter question?

How large of a power inverter would i need to run my 125 amp wire feed from my Jeep. I have a 110 amp alt and Optima red top.

Will I need to hand throttle the motor up?

1) Read the data plate on the back - if it doesn't tell you how many watts it uses, look at the input amps, and multiply by nominal operating voltage (10, 115, or 120 - whatever the number before "VAC" says.) Volts x Amps = Watts. Size accordingly.

2) Probably. Most alternators aren't able to generate full output until 1200 crankshaft RPM or so.

5-90 said:

1) Read the data plate on the back - if it doesn't tell you how many watts it uses, look at the input amps, and multiply by nominal operating voltage (10, 115, or 120 - whatever the number before "VAC" says.) Volts x Amps = Watts. Size accordingly.

2) Probably. Most alternators aren't able to generate full output until 1200 crankshaft RPM or so.

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Thanks 5-90, that was the formula I was looking for. Electrical stuff is not my area of most experiance.

Well my welder is a 115 VAC and a 90A output at 20% duty. Here are the numbers;

115VAC, 60 Hz Standard
Rated Output at 20% Duty Cycle
90 A at 19 VDC63 A at 21 VDC (CSA Rating)
Current Range 30-125 A
Max. Open-Circuit Voltage 29 V
Wire Feed Speed Range 0-415 IPM
0-500 IPM at no load
Amps Input at Rated
Load, 60 Hz 115 V 20
15 CSA Rating kVA 2.9
2.2 CSA Rating kW 2.5
1.77 CSA Rating
Dimensions H: 16 7/8 in (429 mm)
W: 9 7/8 in (251 mm)
D: 12 1/8 in (308 mm) N
net Weight 50 lb (22.7 kg)

That would put me at 11000 watts or am I missing something?

That would be a pricey inverter.

Be carfull with the stated inverter rating. They rate them at a surge level for starting a moter. Continuous use is lower. I did all the math and gave a cusion and it was not enough for what I was using so I'd buy a lot bigger than the math tells you. If you come up with 8-900 watts buy at least a 1500 w or better 2000w if you find a deal.

xjtrailrider said:

Well my welder is a 115 VAC and a 90A output at 20% duty. Here are the numbers;

115VAC, 60 Hz Standard
Rated Output at 20% Duty Cycle
90 A at 19 VDC63 A at 21 VDC (CSA Rating)
Current Range 30-125 A
Max. Open-Circuit Voltage 29 V
Wire Feed Speed Range 0-415 IPM
0-500 IPM at no load
Amps Input at Rated
Load, 60 Hz 115 V 20
15 CSA Rating kVA 2.9
2.2 CSA Rating kW 2.5
1.77 CSA Rating
Dimensions H: 16 7/8 in (429 mm)
W: 9 7/8 in (251 mm)
D: 12 1/8 in (308 mm) N
net Weight 50 lb (22.7 kg)

That would put me at 11000 watts or am I missing something?

That would be a pricey inverter.

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Use 20 amps times 120v or 2400 watts at max load continiouse. 3000 watt inverter would do.

Stumpalump said:

Use 20 amps times 120v or 2400 watts at max load continiouse. 3000 watt inverter would do.

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Thats what I was looking at when I was just guesing. Thats a pricey inverter.