[Home][2015 Index] [TCML] Question for solid-staters [Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[TCML] Question for solid-staters

Continuing on this SSSR scheme of mine, I've now mounted two primary modules, each consisting essentially of 3T on 12"-diameter driven by a p-p pair of MOSFETs, with power source capable of up to ~330 VDC to the MOSFETs and operating at ~125 KHz. There has been discussion here as to whether to connect those two primary drivers effectively in series, using a bifilar choke or chokes to deliver the DC power to them, or whether it will produce just as many ampere-turns merely to connect the two driversto the same DC power source, directly in parallel. In both cases, the gate drives are transformer-coupled. The primaries are coaxial, co-planar, wound with turns close together, and are located directly against the bottom of the secondary.

Fortunately I've made provision for the bifilar chokes because initially, following the simpler connection, I find that a) each primary + driver produces the expected primary currentwhen operated by itself (measured by a current transformer through which 1 turn of each primary passes). However, b) when I connect both of them similarly I get a total primary current increase of only around 10%. This seems to tell me what I had rather suspected, namely that the primaries must be connected effectively in series by means of "floating" at least 3 of the final 4 primary drivers as I describe while galvanically connecting the primaries themselves in series. That's the scheme I'd used years back when I actually got nice spark breakout from the 6x24 toroid, with no breakout point, which I am aiming for again.

I'm guessing that the ~10% increase in current is due to the decrease ineffective dc resistance of the resultant primary, nothing more. So...a little re-wiring will be in order.

Commentswelcome, of course.

Ken Herrick
Tesla mailing list