hvdc

[Dr_Doggy]

hey, Im just wondering about hvdc, how do a get a dc stream of current in a hv, the cloestest thing i can find is all thoes 555 driver circuits, but this creates pulses, I want to build a lifter, I have lots of hv devices, but they are all ac , is there even such thing as dchv, or do I stick with the hf pulses? also im wondering if maybe a ac current would work a lifter, what if I put in a hv capactior, would that rectify my ac signal, I have no hv diodes, is there a cheap method???

 

[Hero999]

You haven't provided enough information.

What voltage at what power level?

 

[john1]

Hi doggy,

It has to be DC for a lifter.
The lifters don't have much lifting power, the DC supply is usually fed
to the lifter from trailing wires, thin ones, from the supply on the
ground. The voltages have to be in the thousands. The current is
insignificant.

They are interesting, but somewhat disapointing projects. They barely
float, and are practically uncontrollable.

You are not going to find chips for this sort of thing.

These things are quite dangerous, and from your apparent inexperience
i would discourage you from making any high voltage equipment unless
you are being supervised by somebody more familiar with this sort
of thing.

Regards, John

 

[Sceadwian]

AC and DC are basically the same thing. If you want to smooth AC into a more DC like signal simple add a properly valued capacitor.

 

[john1]

"AC and DC are basically the same thing. If you want to smooth AC into
a more DC like signal simple add a properly valued capacitor."

You learn something here every day.

John

 

[things]

just get a flyback out of a old monitor, they have internal rectification, and an output current of1-2ma at about 20kv. those values work for a largish lifter, as i have tried it

 

[Dr_Doggy]

ya, im actually useing this application for a diffrent hv expirment, that requires similar specs, and yes a capacitor is used for smoothing, but can it be used for rectification alone? How would I configure it? I understood that if you tune a cap to a inductior it zeros out,
In every rectification method iv seen diodes are used for the rectification process, but how do I rectify a 25kv(low current) ac signal, diodes? where do you find a diode like that? is there a way to maybe make a cheap diode?
The best circuit so far is a 555 timer used to drive a ignition coil, but its a pulse circuit, i know i could use a cap for that, but I have a hv transformer which would be better if I could just plug an play it.

 

[Dr_Doggy]

btw, would a hv pulse run a lifter, if so it may add more control to it

 

[Hero999]

AC and DC are basically the same thing. If you want to smooth AC into a more DC like signal simple add a properly valued capacitor.

You forgot to say that you need a rectifier to convert the DC to AC before you filter it.

 

[things]

just hook up 12 or so 1N4007's in series to the ouput of the ignition coil.

 

[Dr_Doggy]

so what about if I used a hvdc pulse to charge my lifter, would this work?, has anyone tried, any frequencies ever?


another thing I'v always wondered about is a dc pulse that holds no off time, when im analaysing this circuit, it is familiar to an AC signal, with double peak value of course, how similar are theses anyway?

 

[blueroomelectronics]

Ok I give up, what's a "lifter"?

 

[Armagdn03]

if you want a good source of HVDC I would invest in a big vandegraff generator or wiemhurst machine. They are an amperage source rather than a voltage source like many other power sources, and the amperage is quite low, but still easy to make yourself, or buy.

 

[Nigel Goodwin]

if you want a good source of HVDC I would invest in a big vandegraff generator or wiemhurst machine. They are an amperage source rather than a voltage source like many other power sources, and the amperage is quite low, but still easy to make yourself, or buy.

I don't know where you got that from?, but both are generators of static electricity, high voltage and VERY low current.

 

[Gordz]

Ok I give up, what's a "lifter"?

It's a method of using ions to 'lift' something. They are a little unpredictable and an ion driven propeller is an easier method of demonstrating the effect.
Take a look here **broken link removed**

 

[Speakerguy]

EMCO makes inexpensive low power HVDC power supplies.

Google EMCO high voltage and look at their 'F' series. They are adjustable HV supplies, 10 watts, at up to 12kV out. Their output voltage is variable with their input voltage (like you can get a 0-5kV unit that does 2ma out, or a 0-10kV output @ 1ma).

They are about $150 apiece but you don't have to futz around with ignition coils or flybacks if you only need a little current. Nice and small too, PCB mount.

Don't try to rectify and filter HV AC. I've been there. It sucks.

 

[Speakerguy]

Also, if cost is no object, look at Ultravolt high voltage power supplies. 24VDC in, and they have models that will do 30 or 40kV out, very nicely regulated. They are expensive at over $700 for most models (the ones I've used anyway (C30)).

These are what we use at work FWIW.

 

[viper77707]

well i dont see why pulsed hvdc wouldn't work.i mean it would work surely because alot of lifters use just voltage multiplication units to power them and the dont have full-bridge rectification,so it is basically ac...it pulses 30 time/second so it is still ac.and the higher the frequency the higher the negative ions i dont even know alot about lifters but there you go....hope it works for you.(if you use an ignition coil you'd need a multiplier for a big lifter though)