Hi there,
I'm looking for a schematic of an ajustable power supply, for both voltage and amper, from 0 to 45V and 0 to 10A, with digital voltmeter and digital ampermeter.
Does any one have anything like it out there?
Thanks in advance.
Making DC
A 10 A diode is series with 120 vRMS will give you a DC voltage of ~50v. The diode will dissipate 17 W 'cause the RMS value of the current waveform through the diode is higher than 10 A, so you'd need a diode heatsink, maybe with a fan.
The peak voltage is 170v so the downstream capacitors need a V rating of ~350 v [big $$$] unless you don't need filtered DC.
The 600 W transformer for this may cost you $50, and if you want 45 v at the same time you want 10 A, that is, a 450 W output, you'll need a lot of heatsinks or a large Variac.
If you can get specials on smaller xformers, etc., you can parallel them.
If you have four car batteries that you can switch in and out, you can save on the xformer and the huge capacitors and some of the heat sinks, and still get reasonable operating time.
Or you could use a vehicle alternator run by a 1 hp motor [possibly an electric drill]. The diode bridge inside the alt would probably need to be replaced with diodes that can stand the PRV while delivering 45 vdc.
Regulation/filtering
For regulated and filtered voltages National Semiconductor has application notes on how to extend the range of their IC regulators to handle this input voltage and output current. To get voltage regulation down to zero volts you'll probably need a low-current negative supply.
I can't find my paper copy of these notes, but they might already have an entire schematic for this kind of power level.
This sucker is $1400
https://www.bkprecision.com/www/power+supply2.asp
so that is the cost of the parts, and assembly and test time at probably $10/hr.
Misc.
You could also build the raw DC supply and then have various sizes of regulators [1 A, 3 A] and mix and match depending on your need.
Very flexible.
And, for extra voltage/current, you can series/parallel a car battery or batteries with your supply.
Don't forget, if your load resistance doesn't vary you can have 9 A of unregulated current fed into a load, and it's only the last 1 A that is regulated. This takes the burden off the regulator.