Re: flyback TC

On Sat, 16 Oct 1999 12:17:22 -0600 Tesla List <tesla-at-pupman-dot-com> writes:
> Original Poster: "Jim Lux" <jimlux-at-jpl.nasa.gov> 
> > 3. Ihave calculated the output of a cascade multiplier with 60 
> stages to
> > be at least 6kv and 60ma(1kv drop).  Is there any reason for this 
> not
> > working for a TC?

Is should of said about 6kv, 60 ma and 1kv drop actually.
> 60 stages? Running off 110V input to get 6 kV, presumably.  Did you 
> take
> into account the forward voltage drop and IR losses of the 
> rectifiers.

Yes, I did

> is quite difficult to get a 60 stage multiplier to work. The 
> frequency will
> need to be quite high

I did the calculations at 60hz, but I might try to boost the frequency to
a few khz if this works at 60.

 to get 60 mA out, or the caps will need to be 
> fairly
> large.  

I was looking at 10uf

Don't forget that the current in the caps on a multiplier 
> stack is
> significant (well at least 60 mA average, in your case, and much 
> higher
> peak, particularly at the top stages). 
> However, if you have lots of spare time to do the assembly 

Spare time is a commodity in great abundance at the moment.

> you've got
> the caps and diodes, it is worth a try.
> I assume you'd you running an resonant charging scheme with an 
> inductor and
> a diode to charge the tank cap? Don't forget it takes many, many 
> cycles of
> the input for a multiplier to reach nominal output voltage (on the 
> order of
> 2N cycles for a half wave multiplier)
> Just from a construction complexity standpoint, you are probably 
> better off
> finding a surplus HV transformer. Cost is an issue too, 1N4004's 
> would work
> for the diodes and be cheap (for running off 60 Hz), but the caps 
> might not
> (of course, you could use surplus photoflash caps from disposable 
> cameras,
> which you can get for free)

I would be using 1n4007's for 2 cents each from Jameco.  About 200 of
them with a few in parallel on the first stages because they have a
higher duty cycle.  The capacitor's are 20 cents each, 10uf, 105C from

Yeah, you are right about a HV transformer being cheaper,  but I thought
this would be a good learning experience.  It was sort of just a flash of

So is there any reason this would not work?  Has anybody tried this

I am using the calculation:  Vd= I*N/2*pi*f*c
Is this formula correct?



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