Re: Offline Cockroft-Walton

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

Yes, this has been done in the past.

However, to get the 10-15 kV you really need for a TC, you're looking at a
LOT of stages (100?) by which time the multiplier gets really inefficient
(all those diodes in series, if nothing else). CW stacks of more than 10-15
stages seem to be very unusual.  An approach which have been used are: Use a
switchmode power source, so the frequency into the stack is much higher,
even with the low driving voltage.

In any case, by the time you've spent the time and money on the zillions of
components needed for a huge CW stack, you might as well have bought a
higher voltage transformer.  Even if you start with 1000-1500V (which is
very, very common, as in Microwave Oven Transformers), you're better off.


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, May 03, 2003 6:04 AM
Subject: Offline Cockroft-Walton


 > Original poster: "Jolyon Vater Cox by way of Terry Fritz
<teslalist-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>
 >
 > Dear List,
 > Would it not be possible to use a Cockcroft-Walton multiplier to derive a
 > HV DC supply from ordinary domestic mains voltage WITHOUT the need for a
 > high voltage transformer, as these are often difficult to find.
 >
 > I understand that with multipliers of this type, the current available on
 > the HV side is limited  this is often considered a disadvantage but maybe
 > this is a good thing.
 > In any case, can't the output current be increased by having the lower
 > capacitors in the "ladder" connected in parallel and the upper capacitors
 > connected in series?
 >
 > Also, with regard to possible safety hazard of having HV supply directly
 > connected to mains, could this not be mitigated by use of an isolation
 > transformer between the multiplier and mains supply,
 > only isolation transformers seen to be a lot more common and readily
 > available than high voltage transformers appear to be.
 >
 >