two power supplies connected in series.?

Question

I have two 13.8v 20 amp power supplies in series. i want to use a rheostat or potentiometer to adjust just the voltage and keep the 20amps. How should i hook this up and what type pot should i look for? Thanks Scott

Answer 1

I'd like to know what you need 27.6 volts for, at 20 amps? You need to keep both outputs above ground, if you want the total output to go into the load without any difficulties. What you really need is an automatic current/voltage controller. A potentiometer is , as has been stated, very wasteful. You would need one rated at 500 watts, and those cost very big bucks. Tell me what you want to power, I think I can give you some better ideas. Just drop the potentiometer for now. Bad idea, very bad and hugely expensive.

Answer 2

It would help to solve your problem if you could be more specific regarding what you are trying to do. "Keeping" the 20 amps while adjusting the voltage in the circuit you are describing doesn't seem possible. For example If you have a resistive load with 27.6 volts across it and 20 amps flowing through it the resistive value of the load would be 1.38 ohms. If you "somehow" drop the voltage to 13.8 volts there would only be 10 amps flowing through the load. So you haven't "kept" the 20 amps.
This example is only to show that the specifics of your problem as they have been presented do not seem to make sense.

Answer 3

I you want to adjust the voltage then do not do it with a potentiometer, its a waste of energy. Use an electronic control unit for that, especially at the amperages you are using it.
Take care that the potentiometer doesnt explode it might give you a magnificant view but there are better ways to make ann explosion so take care , and always wear ther dark glasses and umbrella agains the fall out

Answer 4

absolutely i tried to connect in sequence both transformer 12v ac. yet first what I did is develop into conscious of the polarity of both both transformer wither subtractive or additive. when I discovered i connect it in sequence similar as on dc grant. it yields extra or a lot less 24vac, then I connect rectifier and capacitor, sure it grant 24 vdc. i'm no longer so positive if the 12vdc appropriate in sequence will artwork. yet as I study it is going to artwork in simple terms grant blocking off diode for safe practices on inner capacitor. confusing to charm to diagram the following I absolutely haven't any scanner. second suggestion: once you've 12vdc, and once you've expertise in electronics, Your means grant is center tap with 2 diode. you could generate 24v by tapping at both ends of the secondary. in simple terms purchase 4 diode of similar score and electrolytic capacitor a minimum of 50volts with minimum of 2200microfarad. connect the diode in bridge type. tnx

Answer 5

Whew...This can be done, but I would use good green pot before I got started.