Herb-RCU

I have a Pyramid power supply that outputs 12V (or 13.8 I think it is to be exact) and 5A. I have read that you can use this as a power supply for cutting foam. My questions are:

1. Can I use it without damaging it? Since it is essentially a direct short, do I need to put anything other than the cutting wire in the output line?

2. What is the best way to regulate its output? My thought was to put some sort of variable resistance in the line from the PS to the wire. I can't find anything at Radio Shack that could properly manage the load. I also thought of a dimmer switch but it has too much resistance even when it is on fully. My last thought was to wire a plug to the dimmer switch and then then an outlet to the dimmer switch. Then plug the PS to this outlet. Would this work? I have experience with house electrical and so this would be easy, but what would it do to the PS?

Thanks for any input!

Herb

jacs

I used my fieldbox battery on 12V and 12A to cut som foam yesterday (red Sunday) okay that it was a little to hot but I shall try with my charger that outputs 12V 1.5A the next cut. Hope this might help you.

PS. This was the first time for me cutting foam but I have read a lot about it.

Steve Lewin

Whatever you do don't try the Dimmer switch. Neither version will work and will probably damage your PSU.

You really need either a very heavy duty variable resistor (expensive and not easy to find) or a 12V speed controller like those sold for small power tools like Minicraft. The other alternative is a Speed controller (ESC) for an RC car/plane, driven from a servo tester.

Steve

Highflight

My Feedback: (4)

Maybe I'm just lucky, but I use one of those cheap and simple car battery chargers. You know, they're about the size of a toaster and have only two switches (6 or 12 volt and 2 amp or 6 amp).
I've found that it works great.
You can probably pick one up at a garage sale for $2.

You plug it's leads to both sides of the cutting bow and have at it.

Highflight

Scott Crownover

I've cut eight cores with a simple 10 amp car battery charger and no power regulator. Just hooked the leads to the ends of my homade bow and cut. Ive cut white foam from Home Depot and EPP foam as well. Works great.


Scott

balsadust-3

Hi
several of us in Idaho used tran. out of game mach. out put was about 12 to 15 volts and about 5 amps. we used a dimmer to control temp. we never burnt up a trans,but was told it was possible to get a shock unless useing a nondirect trans ( whatever that means) only no that four of us used this type of setup for over 10 years. no one shocked or trans burnt up.

chrisbarker

If you have a high amperage transformer(> 3A) of 12v to 24v . You can control it with a router or drill speed controller.
http://www.harborfreight.com/
search for item # 43060
Or there was and earlier thread on this power suply.
http://nsrca.org/technical/tip_trick...wer_supply.htm

Chris

JimCasey

My Feedback: (1)

I use a "ceiling fan" speed controller from Home Depot on the 120V side of the transformer. It's like a dimmer switch, but it is rated for an inductive load. Dimmer switches are only for resistive loads.

Side note: Wal-Mart fishing leader is cheap and makes a spiffy cutting wire.

phuffstatler

My Feedback: (20)

I have an older model train transformer that I use with my Wing Mfg. bow. You can adjust the current to whatever you need. Got it at a swap meet...


phil in austin

Herb-RCU

Well, I went ahead a built a PS from a relatively simple design.

JimCasey, I looked at Wal-Mart for the fishing leader but didn't see it. What kind of package does it come in and how long is it?

Thanks,
Herb

balsadust-3

say I have used quite a varity of wires from uc wire to aircraft safety wire but now use mostly music wire bought in auto supplyers it comes in rolls I try to find about .020 to.024 but not critical larger wire needs more juce thats all if you have availability of stainless welding wire as used in a mig gun good to but to go and buy a spool is kind of spendy and you wont use a roll in three life times for just cutting cores hope this gives you a few ideas.