Original poster: "Gerry Reynolds" <gerryreynolds@xxxxxxxxxxxxx> Hi Malcolm,YES, however, the steady state response from spice using LTR of 1.6*Cres is close to that of an unloaded NST (I just cant remember whether higher or lower). It takes either a transient or feroresonance (as Ed mentioned) to get the voltage higher. Now that I'm thinking about the subject, it seems if ferroresonance occurs at 2.6*Cres, it will occur more at 1.6*Cres cause more of the inductive reactance of the transformer is cancelled by the capacitive reactance of the load (results in higher current limits) and the transformer inductance doesnt need to be reduced as much due to saturation. I just may experiment with this next summer to see where ferroresonance occurs with respect to Cp values.
Gerry R.
Original poster: m.j.watts@xxxxxxxxxxxx
> Original poster: "Gerry Reynolds" <gerryreynolds@xxxxxxxxxxxxx> > > Hi Gary, > > I agree to not let our guard down with LTR. I suspect that when the > variac is slowly cranked up, transients are still being introduced> although they are probably less than when the power is applied all at > once.> > Gerry R The combo is still resonant - it's just that its resonant frequency doesn't exactly correspond with mains frequency. A simple SPICE model should show what happens. There is an element of chaos about the behaviour but you still get peaks and dips in the response. At wide gap settings with the variac cranked up this shows up as erratic firing.