Looking at R2 the 5KW value is based on the magnetron operating at a cathode voltage of  approximately   -4.0KV as discussed previously; about 0.8 A for the 6229 instead of 0.9 for the 7521.

 

The transformer consists of two Fair-Rite toroid type 5943003801 stacked together; the measured and estimated volt-sec for one toroid is about 6E-5 VS per turn 0 to Bmax.  Since two are stacked then the transformer core is double the VS; for 5 turns should have 6E-4 VS which is the parameter value used for the FLUX subcircuit.

 

For a single core the core manual gives AL = 1160nH = L/N2; for N = 5 get 30uH ;  measured 31uH. For two cores stacked the area is doubled giving about 60uH for the primary which is the unsaturated PARAM value used in the FLUX subcircuit.

 

K1 is used as a nearly ideal transformer in that its primary inductance is much greater ( used 4000uH) than the unsaturated value for FLUX. Since Ls /Lp = (Np/Ns)2 then Ls is about 14.1 turns ratio squared times 4000uH = 805000uH which is the PARM value used in the FLUX subcircuit.

 

The details of nanosecond IGBT switch operation is discussed in SSHVSW; basically if the IGBT gate is driven at voltages well above its rated values for sufficiently short times by an avalanche transistor setup then the IGBT can have switching rise times of a few nanoseconds. More details of the pulse modulator will be described later.