How'd you supply your power supply?

[ssutton]

I sourced a 1KVA control transformer out of an old industrial machine for free. It was designed for a primary side of 480VAC single phase and a secondary 120VAC. I just put 120VAC on the primary side and got about 30 volts AC on the secondary. Then, like John Z said, it was a simple matter of a full wave bridge rectifier (they are cheap) and 10, 1000uF capacitors (cheap again) to smooth things out and give the supply a charge supply/dump. I have about 40 volts DC and no clue about current, but running 4 three amp steppers it has never loaded so much to drive down the volts. I have heard that this type of supply is better than a switcher because the electronics in a switcher are always trying to regulate the voltage and therefore surges are not dealt with in the most efficient manner. I would have used a switcher, but when the transformer became available it was a no brainer to build my own. Total cost less than $20.00. Look around at any industrial junk yard, these type transformers are in most 3 phase machines.

If you go this way, this is what you would need if you purchased everything new;

http://www.mpja.com/prodinfo.asp?number=18070+CR (1000uf, 100 volts capacitors, need 10)

http://www.mpja.com/prodinfo.asp?number=5251+BR (35 amp full wave bridge rectifier, need 1)

http://www.automationdirect.com/adc/...VAC/PH1000MQMJ (1 KVA control transformer, need 1 but should be able to find locally for next to nothing)


Scott