[Prev][Next][Index][Thread]
Running without secondary
----------
From: Gary Lau 18-Jun-1998 0758 [SMTP:lau-at-hdecad.ENET.dec-dot-com]
Sent: Thursday, June 18, 1998 7:28 AM
To: tesla-at-pupman-dot-com
Subject: Running without secondary
> Before you try your idea, I thought you should be warned that it is not
>advisable to run your system in the manner you described. I have not tried
>this, but many on the list have said that this is a good way to kill your
>power supply. Apparently, there is no way to dissapate the energy if you run
>without the secondary and it will feed back to your transformer and burn it
>out.
I have heard this advice given many times but I have not heard an
explanation that really explains why. While on the surface, I could see
that if the energy is not going into the top terminal discharge, it must
be going somewhere else. But is it not possible that rather than
quenching after transfering the energy to the secondary, the primary may
just ring for an extended period of time? The energy would be dissipated
in the longer gap conduction period, plus the cap, if not using low-loss
dielectric, would generate more heat due to the longer ringdown, plus
skin effect and other resistive losses, plus radiated EM fields. The
first portion of the ringdown after the gap first conducts will look
identical, regardless of whether there is or is not a secondary, and the
voltages and currents only go down hill from there. There is no "kick
back".
Could it be that the longer ringdown presents the power supply with a
higher duty cycle of high frequency bias, and that it's the extended duty
cycle, not a difference in magnitude, that makes this bad?
Gary Lau
Waltham, MA USA