Sunday, March 31, 2013

My Large Stator for my E-forge

The E-forge will be designed to bring a piece of iron to red hot in seconds using low voltage and high current. This is NOT an induction furnace or a kiln type furnace. This project involves using a homemade transformer to step voltage down to about 2 VAC while increasing the amps many times over. First test was with a microwave oven transformer and achieved 650 amps and melted a 3/16 stainless bolt in half. The next phase involves using a 15 HP ac motor stator and homemade windings to get up to 3,000 amps at about 2 volts through a piece of steel. It will be red hot and ready for shaping in a matter of seconds.

I picked up a large 15 HP AC motor stator today. I think it will work nicely. I paid scrap price for it and will get some of that back when I take out the copper wire and the outer body.

I will be left with just the internal stator made up of metal layers. It should look something like this.

I will then use normal 14/3 house wiring cable and loop it though the “donut” about 50 to 100 times. I can then take the output of wire 1 and connect to the input of wire 2, and the output of wire 2 to the input of wire 3 and the output of wire 3 is the end of the daisy chained wire. So, if I wrap the “donut” 100 times, I effectively have 300 turns on my primary coil. Or if I did 50 wraps, that would be 150 turns. You get the picture.

I might place in a bucket of transmission oil to “Oil Cool” it as well. I don’t think I’ll have to though. The duty cycle is pretty low.


Solar Powered Air Compressor

I had an idea about solar powered pneumatics. What if you had black pvc pipes that heated in the sun? One way for air to get in to the pipes via double check valves, and the way out has double check valves going to a compressor tank or more pipes acting as storage. Make sure the storage is in the shade and the black pipes are in the sun.  The sun heats the black pipes, air inside expands and can only go to the air storage tank until equilibrium is reached. At night, the pvc pipes cool and suck in air, and repeat the process the next day. It would also, somewhat repeat a cycle with a passing cloud. Also, having about 2 or 3 times more heated volume than the tank will mean the tank could be filled in one day. 



I originally came up with this idea for a friend that needed a few psi air pressure to slowly push a drip irrigation system. Last night I decided to check the math and used an ideal gas law equation.

P2 = P1 (T2/T1) where P is pressure and T is temperature in kelvin.

It turns out that going from 50 F to about 120F on a sunny day (even though the outside temp may be 85 to 90F, the black pipes will easily heat up to over 100F.), would only produce about 2 psi of pressure. So, this has very limited applications. You might be able to use black metal pipes and use a giant Fresnel lens to heat it, but that would only produce about 50 to 60 psi. Not that efficient.

Probably a lot better to just use a small solar panel and a small air pump that charges a tank.

Friday, March 22, 2013

Homemade Hot-wire Acrylic Bender

I threw some scrap together today; aluminum tape, wood, screws, and 20 AWG stainless steel wire. I power it with either a 12 volt battery or a battery charger. It draws about 7 amps at 13 volts, or about 90 watts. I twisted the wire using a drill to make it like a spring. This concentrates the heat in a smaller area and also allows for metal expansion and stops the drooping effect.

Here is a couple of laser cut acrylic stepper motor mounts bent on my hot wire bender.

Tuesday, March 19, 2013

Poor man's Homemade DIY CNC

Made some more progress. I have the upright fixed arms installed and I laser cut acrylic bearing blocks for the Y axis.