Body
HI Mick
I do buy individual mosfetsm parallel them and hook them up in bidirectional fashion (gates connect and source leads connect, switching happens between drain A and drain B) - and si U tear out the mosfet inside the SSR (usually this has blown up so good reason to convert these to bidirectional mosfet switching for peak coil shorting)
The method I do is not to have a closed coil (shorted out) in first place, then pulse it, but rather opposite, that is to have open coil, and either pulse it with DC and then time the short of the coil to happen just before it saturates,
(this Ismael method for his MEG and other stuff)
or, what I usually do is have a generator coil (air coil or coil with very fast core material) and sweep a magnet past the coil to induce some power (permanent magnet rotor and stationary generator coil)
then at the peak period of the sinewave that will happen, that is when I short the coil with a switch with a fairly narrow pulse width...
mosfets conduct only one way, so to keep the hyper ringing happening (rings during the switch closure period! NOT when switch opens, which is other animal - the flyback/backemf recoil spike in a pulsed DC inductor)
So to sustain the rringing which is those AC spikey clusters seen in link below, you need a switch that switches AC and lets the AC "flow" too within the switch.. so that is why bidirectional mosfets...
Here is circuit I do for peak coil shorting....note also the diode going from source to drain on each mosfet:..look at the scope shot at bottom of page, this is 60hz generator coil signal (neo magnet past big aircoil) and look at the ringing that happens when the coil is shorted at that peak period...in this case with mechanical brush-commutator....
The middle drawing on this page shows a simple two-stage output circuit where first caps fill by themselves, then caps discharge by themselves which is required in peak coil shorting circuits to extract power without killing everything with a direct resistive load.
https://sites.google.com/site/alternativeworldenergy/shorting-coils-circuits https://sites.google.com/site/alternativeworldenergy/shorting-coils-circuits