1.5 to 37 Volt 30 Amp
Power Supply
Circuit : Max, Ohio USA.
Email  : irondmax@yahoo.com
Web :   Project Icarus

A modification to the 12V 30 Amp power supply. This version uses an LM317 to provide a variable 1.5 to 37 Volt regulated output with currents up to 30 Amps. Max has built his power supply into an old computer case and can be seen on YouTube under Project Icarus.

1.5 to 30 volt high current variable power supply circuit Notes
I wanted an adjustable power supply from 1.5 volts to 37 volts, based on the LM317 voltage regulator chip. Simple to remove the 12 volt regulator chip and add the LM317 chip and a 240 resistor, a 10k pot and a 1N4007 diode. Just as easy to insert any of the other voltage chips as well.

I used an old computer tower to house my project, used the heat sinks from the computer power supply for the power transistors. The heat sink for the LM317 came from an old TV, and the heat sink and fan for the bridged rectifier came from the old computer processor. I found the transformer at a flea market.

Also added was a small transformer from an old radio. Rated at 14 volts and small amps.This transformer powers two 12 volt regulator chips wired together on the same heatsink. Wired together there output is 12 volts and 3 amps. This is power for 2 fans and power for the digital volt meter and amp meter. The volt meter is powered at 5 volts, so another 5 volt chip was added on another circuit board. Digital amp meters use a shunt to measure the amperage, and the power supply needs to be isolated, easy enough, just use an isolation chip designed for this purpose. Also I used 10 amp output jacks, plus 10-24 bolts with wing nuts. The bolts are for 10 to 30 amps.

Here in the USA, we use 110 volt mains and 220 volt mains. The transformer I found can be wired for either input, and can can be wired as 16 volt or 32 volt output. 16 volt AC through the bridged rectifier and into the 47,000uf capacitor, comes out as 19 volts. This is caused by the voltage ripple peak into the capacitor. This caused a problem because the 32 volt AC input comes out as 44 volt DC, and the LM317 chip is listed as 40 volt maximum. So currently I am using the 16 volt AC output from the transformer. After some experiments I plan to try the 44 volt DC and see if the LM317 can handle it.

Check out my YouTube Channel or search "Irondmax" on YouTube. Good luck and have fun.

A Finished Project
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