Hello !

I need to switch on and off the output of this transformer that has been rectified with a full bridge rectifier.

The switching frequency will be at a maximum of a few Hertz so no need for crazy switching speed.

What would be the best solution for my problem ?

Thank you for your answers,
Have a nice day

 

Did you do a search? I came up with this for example:

High voltage relays:


Bob

 

Switch the input of the "transformer" not the output.

 

And be careful!

 

Switch the input of the "transformer" not the output.

That might not be practical at a few Hertz.

Bob

 

That might not be practical

I have some high voltage relays, but the price is 1000 times the cost of the transformer.

 

Assuming the power supply is rectified with filter capacitors, switching the input would not give a sharp transition in the output. It depends on how fast rise and fall times the TS needs.

I do expect a switch at of any kind fir that kind if voltage to be expensive.

Bob

 

If that is +15 kV that could switched on and off and a second high voltage power supply (flyback preferred) could be used (inside a loop) to drive down the voltage quickly.

 

A vacuum relay as in post #6, but you have to find one that handles your current and can withstand 15kv.
The higher the voltage rating, the higher the price. Most 15kv+ vacuum relays will handle multiple amps. Cost is around $300USD, give or take a bit.
Cheapest I've seen is:
https://mgs4u.com/product/vc-2/

 

Looking at the "transformer" link, it seems to be a simply flyback transformer. You should be able to switch the primary at a couple of Hertz I would think, assuming you are using the raw output of the flyback transformer (no capacitors).
Also, that device seems to be using a transistor on board to do the switching. Turning the transistor on/off may be another way to turn the HV on/off. You would have to trace out the circuit to see how the transistor works...

 

PS: No way you are going to get 0.4A from that device as your title suggests, more likely 0.4mA

 

You're right! This is not a 6 kW power supply. Don't worry about the current, just worry about the voltage. Look at the size of the transformer and the heatsink compared to the switch. My guess is way less than 10 watts.

 

Not amps but mA. 0.0004A
0.4mA is 6watts. That is probably too high. If the current is 0.4mA then 8W in and 6W out. I think it cannot be more than 50% efficient so maybe 4 watts out.

Because we can't see the entire project, we are just guessing. Probably an electric fence.

 

Good point Ron!

In which case the thread starter should be looking at electric fence chargers, which are usually if not always designed to jolt but not injure or kill an animal touching or otherwise coming into contact with it.

Too many times people have been killed by poorly designed electric fences. Here are some related threads on this site:

https://forum.allaboutcircuits.com/threads/how-to-make-an-electric-fence.178326/
https://forum.allaboutcircuits.com/threads/diy-electric-fence-engergizer.95938/
https://forum.allaboutcircuits.com/threads/how-to-make-an-electric-fence.178066/

 

He also said that it is rectified by a bridge. The photo shows just the wires directly out if the transformer, so either he is misinformed or that is not the entire circuit.

Bob

 

Switch the input of the "transformer" not the output.

I can't really do that, the transformer is charging high voltage capacitors and I need a way to control when I bleed them through a resitor, that's why I want to switch the output. I've mislead you by linking the transformer but my main problem is the control of the bleeding.

 

He also said that it is rectified by a bridge. The photo shows just the wires directly out if the transformer, so either he is misinformed or that is not the entire circuit.

Bob

I added a full bridge rectifier myself

 

I added a full bridge rectifier myself

Post a schematic, even hand drawn, so we can better understand...
A full bridge rectifier for 15kv is not trivial....