Welding Tips and Tricks

I'm considering buying an ac/dc inverter to get started doing some side jobs (such as Al boat repairs) and it would help to be portable.

I'd be using my miller 250D bobcat as the power source. Since I'm not real familiar with inverters, is it OK to use my bobcat as power source?

The inverters I'm looking at is the ahp alphatig and the everlast 250ex. With two kids in college, the ahp is very appealing due to the price, leaving room to upgrade torch, pedal, etc. Plus, with price, it would pay for itself quickly.

But, I really like the everlast 250ex due to the added features And extra amperage. But, I know I'd want to upgrade the torch and pedal.

Any info, recommendations, or thoughts will be greatly appreciated. Thanks

The best advice you can get on this would be directly from the manufacturer. They should have an applications engineer available to give you good advice on their equipment.

Inverter welders will generally require a "clean power" rated generator to run safely and within warranty. This means a generator rated to a narrow frequency range around 60Hz, as well as damping of harmonic frequencies (generally multiples of 60Hz) that are common in simple generators designed to run your grinder or chop-saw.

I would first consult the manufacturer of the inverter for the input requirement, then review Miller's detailed literature on the machine. If not satisfied, I'd contact Miller directly to make sure the output of the Bobcat will meet the requirements of the machine you choose.

Tread carefully here to avoid voiding a warranty.

Steve S

Using Watt's Law, a PowerTig250EX, which has a maximum inrush current of 50A (which is why it requires a 50A service) you would need an 11,000 watt generator at 220V (which is the voltage on them). P (watts) = I (amperage) x E (voltage). Also, it says that directly on their website that they require a minimum of 11,000W of clean power as Steve stated.

I don't have any first hand experience with this but when I was considering buying a New Tig machine and investigating inverters my LWS said this was the number one reason the inverters burn up. I believe he said something about inconsistent supply voltage. I'm not saying they said it can't or shouldn't be done he just warned me about that. Good luck

GreinTime wrote:Using Watt's Law, a PowerTig250EX, which has a maximum inrush current of 50A (which is why it requires a 50A service) you would need an 11,000 watt generator at 220V (which is the voltage on them). P (watts) = I (amperage) x E (voltage). Also, it says that directly on their website that they require a minimum of 11,000W of clean power as Steve stated.

Well I guess that answers it for the 250ex. The bobcat is rated at 10,500w.

I'll have to do some checking on the the ahp.


Although having the bobcat as a power source would be nice, it's not a necessity.

Check with Everlast or on their Web site. I belive the 250EXT is designed to be used with an "Unclean" power source