How to Make a Power Supply

[jatt]

Hi all,

This is my first post here.  Have done a bit of experimenting in the past with basic power supplies.

This is aimed more for those who dont know much about capacitors.

When I was building things I would use 105 degree rated units at the very least.  Personaly I dont feel the 85 deg are suitable for the task, especially when there is a fair amount of heat involved.

From personal experience I recon the grey insulating material that is shown to back the regulator case to the heatsink is a better way to go than the clear mica washers.  Found the mica splits easily.


Happy power supply building

[websterz]

Finally in this picture you can see that I have added a push to break switch inline with the adjusting pot. It's the one with the red button.

When the adjusting pot is turned to a higher resistance setting this will increase the speed of the motor. Lower resistance lowers the motor speed.
The "push" switch breaks the circuit offering an infinity resistance, ie very high. When the button is pushed the motor will spin at full speed. Useful for rapid transverse.
Let go of the button and the motor will resume to the pot setting speed as set previously.
This is useful not only for momentary rapid transverse of the mill bed, but it also allows you to leave the pot alone when you have found a comfortable cutting speed.

Quick question Darren. My homebrew power feed utilizes a 14.4 volt cordless drill motor and an ATX computer power supply. I control the speed with this controller:


I added a DPDT switch between the controller and the motor for reversing the table feed. It all works very well...I am shocked I was able to get it to do what I wanted actually. You should see my collection of burned out controllers and power supplies!  Anyway, the only feature my set-up lacks is the rapid traverse you talked about. With my controller and power supply arrangement can I add a "go really fast" button like your's?   

[Darren]

The short answer is I'm not sure, only because I don't know the circuit.

But that pot is the voltage/speed control so I guess then yes you can. All my go faster button did was create a high resistance as in an open circuit. Push to break switch in series with the pot connection.

So I guess you will be able to do the same.

[websterz]

With the pot on mine being mounted to the pcb it would involve a certain level of disassembly I am sure. I think I'll just be content that it works as-is and not start pulling stuff apart.