[TCML] c/w multiplier coil

[Peter Terren]

Firstly, never directly short a multiplier. You are short circuiting the 
caps through the diodes and they die. Use a series resistance to limit it.
Secondly, when running a multiplier in to an inductive load there will be a 
resonance with the caps and inductance. After the first half cycle the 
multiplier will be feeding into not only a short circuit but an equivalent 
voltage in the REVERSE direction resulting in a huge current and the diodes 
die. Ie a 10kV multiplier will face a 20kV short circuit.
I have seen more than one person seem surprised when they blow multipliers 
because they don't realise the above 2 points.
I built a 4 stage single MOT multiplier yesterday which runs about 70mA 8kV 
DC referenced to earth ie 560W.  It is 12kV open circuit. This is a lot more 
than an NST (even a 15/60) which would only manage open circuit 7.5 X 1.4 = 
10.5kV no load referenced to earth and guessing about 7.5kV under 40mA 
(300W) load rectified.
I use a 50 or 100K 200W resistor as a load or part of that as a series 
resistor if I want to pull some arcs. Works nicely for short runs.

Peter
www.tesladownunder.com


----- Original Message ----- 
From: "Clive Hansen" <mrclivehansen at gmail.com>


> Hello Everyone,
>    Some time ago I built a Crockroft-Walton multiplier to quintuple the 
> voltage of a power supply for use with a small coil. Recently, the 
> multiplier was hissing and losing a lot of power to corona. So, I decided 
> to operate it under oil in a coffee can since it is a small multiplier. I 
> sunk the whole multiplier in a coffee can filled with motor oil. The can 
> is metal, but the components are all at least 3/4 inches from the sides. 
> The assembly worked exceptionally the first several times I ran it. 
> However, when I power it up now, there are no sparks from the coil. 
> Directly shorting the multiplier yields only 2-3mm long sparks which are 
> very faint, whereas before it would produce 1.5in sparks when shorted. 
> Also, when powered on, the transformer makes an odd clicking noise which I 
> did not notice before. Does anybody know what the problem is here?
>
> Thanks,
> Clive