Large Scale Central

Home Made Power Supply

Electronics Power and Sound
#1

After some research trying to decide weather to go analog or DCC I decided to begin scratch building my own power supply and see how I make out. So far I have build a 120vac 15amp input and 30vdc 10amp output. Now That I have a good stable 30vdc out I want to take this output and give it a 0-24vdc variable. I will post a few pictures this weekend.

Now I am looking at making a PWM circuit with some sort of sliding bar throttle system but running out of ideas as to what components to use. Has anyone out there tried to make a power supply? Anyone have any ideas as to what to use to vary the voltage?

#2

Jason -

If you want to build it yourself I can’t be of much help other than to say the best design would be to vary a small input voltage that varies the power transistors in your high current supply. This would be more efficient than varying the output.

If you’d rather not build it, AristoCraft makes a throttle that will take your 30V supply, convert it to PWM and give you a variable output. It has a rotary, rather than a linear control. -OR- If you’d like a hand held wireless throttle both RCS and AristoCraft make what is called a track side receiver which is a throttle for their remote control that feeds the track.

Long ago, in HO I had a fixed output supply that I wanted to use. I ended up using a VARIAC between the transformer and the AC to DC conversion. It was the cheapest solution for me because I had the VARIAC.

#3

Made lots of power supplies. My first college degree was in Electronics.

Off hand, I’m thinking of a 1 transistor constant current source feeding a capacitor to get a sawtooth waveform, and an op-amp used as a comparator to compare the capacitor voltage to the tap of a sliding pot and drive a hexfet.

I really don’t have time to draw it and figure out values right now.

#4

Here are a couple of pictures as to where I am at with my power supply.

(http://users.eastlink.ca/~brownscountry/PsupGscale1.jpg)

The unit is heavy duty and will withstand some abuse. The components inside are of marine grade and very tough.

(http://users.eastlink.ca/~brownscountry/PsupGin.jpg)

Input 120vac 15amp Output 120vac 15amp 21vac 10amp 29vdc 10amp I am still exploring how to vary the voltage. I am searching for a PWM circuit card that can handle 10amps

#5

Wow Jason, looks pretty darned professional, to a electronics lacking guy.

#6

15 amp pwm controller - http://www.bakatronics.com/shop/item.aspx?itemid=444

30 amp - http://www.bakatronics.com/shop/item.aspx?itemid=581 , http://www.bakatronics.com/shop/item.aspx?itemid=679

-Brian

#7

Nice work!