How to convert 300 volts DC to 30 volts DC?

Alright so i made a simple full bridge rectifier (http://www.electroboom.com/?p=544) credits to Medhi Sadahagar. I modified it such that it works with 240 volts mains instead of 120 volts mains. my capacitor bank is 2.4 mF and 400 volts. However, the output is 312 volts DC and I require around 12-36 volts DC at minimum 10 amps to power a ZVS driver (by Plasmana). I tried a voltage divider but I think the power rating of my resistors was not enough as one of them heated up and broke. I need help in designing or making a suitable circuit to reduce 312 volts DC to 12-36 volts DC at 10 amps minimum. Please help me and have a great day :D 

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Yonatan241 year ago

You need a transformer, You can probably get them on eBay for not that expensive but it depends how many amps you need... 10 amps should be pretty expensive

Voltage devider for 10 amps?
Did you use halogen light bars, ceramic room heaters or an old oil heater for the devider???
Don't want to spoil your work but for the power levels you are talking about you are better off with a stick welder and bridge rectifier at the output.
If you use one with a regulator for the welding current you can even adjust the output.
But for those amps you need serious rectifier diodes or several bridge rectifiers in parallel on big heat sinks.
The big rectifier go to about 25amps on a good heat sink if you want to keep the size small.

BenderSanchez (author)  Downunder35m2 years ago

Thanks :D

verence2 years ago

Voltage dividers are for signals (audio, measurement probes) not for power.

With power, you use a transformer to bring the voltage down (or up) and rectify/regulate on the target voltage. If size is a concern, use a switching power supply.

BenderSanchez (author)  verence2 years ago

Thanks :D

Transformer down first then rectify with diodes.

Sounds like a booster or a fast car battery charger will do you.

Just remove the circuit board and add your rectifier.

You can get high amperage components here.


BenderSanchez (author)  Josehf Murchison2 years ago

Thanks :D

I suggest trying to find, (i.e buy, borrow, or steal) a power supply with specs approximately equal to what you want.

For example, in my junk pile, I found a power adapter brick for a Xbox 360. The plate on it says it can supply 12 volts, at 16.5 amperes.

BenderSanchez (author)  Jack A Lopez2 years ago

Thanks :D

-max-2 years ago

Yeah, basicly it is going to be cheaper if you just buy a power supply for the job. I took an old XBOX power supply rated for 12V 12A, and modified it by shorting one of the optocouplers connected that was used for foldback current limiting to stop the supply from shutting off completly when I get some inrush current from my ZVS circuit.

BenderSanchez (author)  -max-2 years ago

Thanks :D