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Old Sep 05, 2012, 07:45 PM
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Southern Vermont
Joined Feb 2007
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EDIT: Just noticed that you are in GB (no Harbor Freight) and also had already used the calculator to determine specs for a 1 meter bow. And that the power supply seems reasonable to you in cost.

So to answer your questions:

1.) The capability to supply more amps than you need is fine. That is normal and desirable. You actually don't want a power supply that is operating at the edge of its current supplying capability.

2.) There is no danger from electrocution on the output terminals on a responsibly designed undamaged 15 volt power supply.

3.) In a low voltage supply like this one you can size your hot wire thin enough that it couldn't draw more than say 3.5 - 4 amps maximum at 15 volts. It will still get quite hot at the maximum setting, and you would normally cut a little cooler than that. But it won't be able to draw 15 amps, because the resistance of the wire is too high to allow it. For best protection you want to be cutting just a little under max range available, rather than say cutting at 25% of full range. Sizing your wire properly will do that.

4.) A fuse normally protects currents above the output maximum (15 amps in this case) or the mains current above a value the manufacturer deems damaging to the unit. That would not protect against fire if an improperly sized wire was connected to it that drew less than 15 amps.

The main danger for a hot wire setup that is properly designed and sized to the bow would be simply leaving the bow at a maximum setting in contact with something flammable, or shorting the hot wire terminals and creating a lot of heat with a shorter or lower resistance wire than you normally use.


I do need to put in a disclaimer here however. Operating a power supply and hot wire cutter must be at your own risk. You need to be responsible for determining the safety of any rig you put together and operate. I may not have covered all of the potential issues here. Just trying to provide information I'm aware of. I'm sure others will chime in if I've missed something.
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Last edited by vtdiy; Sep 05, 2012 at 08:35 PM.
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