Confused about how this induction circuit works :/

[ivyandnine]

Hello all :-)

I've been trying to understand this induction circuit for weeks but have been having some difficulties.

From what I've tried to guess so far, there is some kind of resonance network between C1, C2, L1, L2 and L3 and the diodes act as some sort of
a detector that turns off the FET they are connected to when the resonant network swings from one side to the other?

Some questions that come to mind here are:
(1) Why does the heating coil (L1) not have an induction value? Is it's inductance inconsequential and the symbol is just shown so that you know what it is?
(2) How exactly does the resonance network between C1, C2, L1, L2, and L3 work?
(3) How were the values of 330nF and 100uH chosen for the capacitors and inductors?

I've also tried simulating this in OrCAD but nothing happens...

Any help / insight in understanding this is appreciated <3

[helius]

The two MOSFETs are "racing" to switch each other off. In any real circuit, one will be faster and win, which starts the circuit oscillating.
To simulate this, you need to change some of the component values so the two sides aren't equal. Try increasing R1 in relation to R2 by 10%.