Power Problems

After a rather fruitless search to find an arc wielder that would be able to supply our power needs, the lab group has taken matters into our own hands. Since our power needs are very unusual, we require 20V at 100A for a 100% duty cycle, only the high-end arc wielders are able to provide us with the right amount of power. Not only are these arc wielders outside of our price range, but the require high voltage, high amperage power circuits which our lab does not have.

So we have decided to, in a way, build our own power supply. Our current plan is to create a network of transformers to power the system.

Today in the lab, Travis, Jon and myself tested to see if transformers in parallel would work the same way as resistors. This means the voltage across the transformers would be equal, in this case they supplied 12.6V, but the current through the transformers would sum up to the total current in the circuit. After running several tests we were able to observe a 5.34A current through a melting 2 ohm resistor. The resistor was only rated to 10W so the longer we ran the circuit, the more the resistor failed. This is a very promising result because it means that we can use multiple transformers in parallel to allow us to reach a high current at around 20V.

The only hesitations I have still is that we did not run the transformers very long, I expect that the transformers should be able to exceed 3A by themselves for short periods of time, so this could be what was happening. Unfortunately any attempt to run the transformers longer than 20-30 seconds or so was prevented because the resistors hit about 210 degrees C according to our infrared thermometer. I also did not think to test the current through each transformer, so we can't be sure if one had more load than the other.

Oh and I thought I would mention Travis had fun lighting up a section of NiCr wire like a toaster by putting 6A through it. We measured temps of around 210 degrees C!!

~Kyle