Home Brewed Power Supply

[letmefixit]

Ok i need some excitment in my life. I want to build my own power supply. Im going to be running 3-600 oz servo's 600 peak 90V/38amp. Does anyone have any plans or suggestions for parts and materials.

DJ

[Bubba]

DJ,
OK, not to toot my own horn, but follow this and it will give you some ideas on persuading this project.

http://www.cnczone.com/modules.php?n...warticle&id=27

There is a lot of information on this site on sizing of the power supply and if you follow it, it will lead you down the path of success. :})

[letmefixit]

Oh my word... that looks like real work. so what size of transformer??

[davidmb]

Alternate approach:

Buy a toroidal transformer that is slightly higher voltage than you need and take windings off, I have done this now for two power supplies, it's a bit of a pain because the mylar tape that is used for the outside insulation needs to be
threaded through the toroid on each turn, but this was the only way I could get a transformer that would output the voltage I needed using just a simple linear psu model ( bridge rectifier and a big capacitor ).

[Bubba]

DJ,
The size of the transformer (wattage) will depend on the size you scrounge from an old microwave. Personally, I only look at the ones in the 1800 watt range for my supplies. Its like HP in an engine. If I don't use it, it costs (relatively) nothing. However I know its there if I need it for some reason.

The last one I did is roughly 2.5 x 3 4" high. On this, I wound a high voltage to use on the stepper, and two low voltage windings to be use for 5V and 12V supplies.

[vger]

DJ,
Lets see... 38 Amps at 90 Volts... thats a little under 3500 watts. If you plan on running on 120 Volts AC then you are gonna need a 30 Amp service to the power supply... would probably be better to use 220 Volts for that much power. A 3500 watt transformer will be quite heavy, like about 40 Lbs. A microwave oven transformer will not be big enough, unless you parallel 4 of them, and they would have to be nearly identical to one another. Is that 38A at 90V per servo? If so... you should probably do a supply for each servo/amp and do a 50 Amp 220 volt service to the supplies.

Steve

[Bubba]

If he is going to use Gecko's, max voltage should be around 72V. He states the PEAK amp is 38 and that is a thou shalt not exceed condition. Real world max continuous amperage will be 7.8 Amps! So now, for normal running, we are looking at 72*7.8=561 watts and yes, you will want some more for acceleration usage, but I can't for the life of me see the need for 38 AMPS!

Some calculations are really needed to find out what the system will require.