need help with volts and amps

[Groundloop]

Hi Groundloop

I have around 2000 volts DC (20 milliamps) , can I use the microwave transformer with some oscillator?

for me it is also ok to have AC as the final output (up to 50 V) 

Thanks

Grone,

If you can find a transistor (MOSFET) that can handle 2000 Volt, then it is possible
to make a voltage downconverter. I'm currently on vacation with very limited Internet
connection but I will look into your problem sometime later on.

Groundloop.

[TinselKoala]

You need an "inverse Marx bank" or C-W generator. The way to do it is to take a bunch of individual capacitors.... how many? 2000/12 many.

Put these in series and charge up the whole stack. Then disconnect them and put them in parallel and use that to charge up another cap of greater capacity but lower (24 ) voltage. Then run your load off of the 12 volts on this capacitor.

You may need to figure out how to make the switch from series to parallel for your cap bank. I don't know how to do it electronically but it can be done mechanically with a clever arrangement of contacts and levers.

[fritz]

Even an unloaded microwave transformer operated in reverse would need significant magnetizing current which would lead in combination with a HV H-bridge to significant losses / poor efficiency if just 12Watt dissipated.
For a supply with few hundred watts (what this transformer is designed for) - this would be an appropriate approach.

A marx bank is somewhat the high voltage sister of a chargepump supply.
To protect the capacitors from overvoltage, a marxbank is using resistors - which impacts the efficiency.
Anyway, you would need perfectly isolating switching stages.

So I still think there is at least a two-step approach feasible - winding your own HV coils - and designing some HV-Switches (stacked up mosfet or transistor ladders)

rgds.

[Grone]

Thanks! 

[Groundloop]

Grone,

Attached is a circuit that MIGHT work for you. This circuit uses a transient protector as a spark gap
and will switch on at approx. 1600 Volt DC and off again at approx. 300 Volt DC. (+/-20%)
The 2000 Volt DC input will charge up the four series capacitors, and when the voltage is
high enough, then the transient protector will discharge the capacitors into the transformer primary.
The input resistor is a current limiter and will ensure that the capacitors will discharge to a low
enough voltage so that the transient protector will switch off again. And the cycle repeats.
The Ferrite transformer must be home made. See drawing for winding ratio. Be careful when
operating the circuit at 2000 Volt. The capacitor charge can do serious damage to your body!
If you need exactly 12 VDC at the output then you can use a 7812 voltage regulator.

Groundloop.