Re: ignition coil
From: Malcolm Watts[SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: Wednesday, July 23, 1997 1:29 AM
Subject: Re: ignition coil
Hello Alfred, all,
> > (2) How to get _all_ energy from the core to the secondary? Not easy.
> > You have to break the supply from the primary without a spark across
> > the break contacts. Fast parting contacts are the order of the day.
> > You can slow the rate of rise of core energy release by putting a
> > small capacitor across the contacts, the ideal being that the
> > contacts part company faster than the voltage across them rises.
> Malcolm, I find nothing wrong with what you said except that it
> ignores one of Michael Faradays most important observations, namely
> that the faster that the current is cut off from an inductor the
> faster the magnetic field collapses and the higher the induced
> voltage. It was to this end that Tesla started out with a mercury
> turbine interuptor for his initial H.V. generators and it was what
> lead Tesla to the design of the Tesla coil itself.
Firstly, quite true. However, energy lost in the primary = energy not
dissipated in the secondary discharge. The cap needn't be huge.
Then again, TC's can be rather slow at low operating frequencies
I stand modified.