dc welder

[Diehard]

i have a small two stroke dc welder with a dc plug for grinders or other devices. my question is ,is it possible to make the plug in work with ac tools?

[slamdvw]

mostlikely not. Kind of sounds like the outlet on a lincoln, powered off the exciter. Pure DC output.

you *might* be able to find an inverter that will work with that voltage... I don't know

[Diehard]

i didnt think it would work but it was worth a shot, thanks Slamdvw

[awright]

What is the DC voltage at the receptacle? What are you referring to as "...AC tools"?

Almost all hand-held, portable rotary tools have "universal" motors and will work fine on DC of the proper voltage. Most line powered portable rotary tools have universal motors because of the high power/weight ratio of universal motors. Universal motors can be easily recognized by the two brush holders usually visible on opposite sides of the motor.

Tools with induction motors will burn up very quickly on DC - possibly before you could react and unplug them. This would include most belt-driven tools or bench mounted grinders and buffers, although some bench mounted tools use brush motors.

I hope these comments are not too rudimentary for you, but It wasn't clear what type of AC tools you are thinking of.

Any induction motor driven tool would require an inverter to convert the DC power from your welder to AC line power. A suitable inverter would have to accept the DC voltage available from your welder and I'm not sure how readily available such an inverter would be.

awright

[tessdad]

Re; DC power to tools
I am not sure of this. I was told a while back that power tools with an on off type switch will be safe, but tools with a variable speed switch, like most drills, might burn up the control.

[awright]

My bad! tessdad is mostly correct!

I was (carelessly) limited my thinking to fixed speed tools without variable speed controls, since I suppose I don't use variable speed tools much around my welding projects and they were out of mind. (Still trying to scrape a little honor off the floor, here.)

However, considering the basic function of VS controls (triac chopping the AC wavefore and relying on the zero-crossing of the current waveform to commutate (turn off) the triac, I think a VS tool would not be damaged by DC power, but would simply latch in the full speed position like a simple switch, not hurting anything. I think the tool would simply revert to uncontrolled on-off function. If the tool's control did not incorporate a switch to open the circuit when the trigger was released but instead relied on the triac to turn off the tool, the user would have to pull the plug to turn it off. Not a safe condition.

Still, I would not gamble your VS tool on my analysis (since, clearly, I've been wrong before) and would simply not use a VS tool with DC power. Thanks for the wake-up call, tessdad.

What types of tools WERE you thinking about, Diehard?

awright

[Diehard]

i was thinking ,mostly about hand grinders and maybe a drill. i dont use this little welder very much but it is pretty handy when you just need something really portable and your a long way from a plugin.

[slamdvw]

for those tools, yes they'll work off that DC outlet. just about anything with brushes. regular plain incandescent light bulbs will also work ( then again, don't the arc give off enough light? )

[tresi]

What is the DC voltage at the receptacle? What are you referring to as "...AC tools"?

Almost all hand-held, portable rotary tools have "universal" motors and will work fine on DC of the proper voltage. Most line powered portable rotary tools have universal motors because of the high power/weight ratio of universal motors. Universal motors can be easily recognized by the two brush holders usually visible on opposite sides of the motor.

Tools with induction motors will burn up very quickly on DC - possibly before you could react and unplug them. This would include most belt-driven tools or bench mounted grinders and buffers, although some bench mounted tools use brush motors.

I hope these comments are not too rudimentary for you, but It wasn't clear what type of AC tools you are thinking of.

Any induction motor driven tool would require an inverter to convert the DC power from your welder to AC line power. A suitable inverter would have to accept the DC voltage available from your welder and I'm not sure how readily available such an inverter would be.

awright
Many years when I was in school several old timers told me that when trying to run variable speed tools off of DC that you must alway pull the trigger wide open for the tool to work right and not be damaged. Of course this conversation mainly concerned variable speed drills made in the 70's and early 80's. The only portables that I've used always had plenty of AC power so I've never tried it for myself.

[Diehard]

thanks guys, nice to know my grinders will work. thats a much needed tool in the field. as for light bulbs i dont think i need them, this little box really puts out some fire. it amazed me the first time i used it.

[TEK]

Variable speed tools will burn out if used on a dc power source. Been there.Saw it. Grinders and Skil saws are fine but a vs will roast the trigger.

[Diehard]

thanks Tek, im assuming that a one speed drill will work? just nothing variable.