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THOR problems follow-up
Hello.
In my last email there were basically two open issues:
1. How to get higher charging voltage
2. Reduced performance after warm-up
I did yesterday more simulation and measurements.
1. Higher charging voltage
---------------------------------------
Here the basic problem is that the capacitor charging profile with my SMPS is
not as steep (as a straight line) as it should be according to my simulations.
Then I recalled I have about 4 mH of inductance in series between the SMPS and
the primary cap: it is the HF filter for protecting the SMPS from transients.
After some MicroSim runs I noticed that those few mH do make a difference:
Actually they bend the charge profile and even lower the top charging voltage:
this is due to the fact that the SMPS charges the cap with pulses, not as with
an NST or pig.
I made some measurements with the filter bypassed and the charge profile does
get better, but not radically. Check picture #9 at "
http://www.saunalahti.fi/dncmrc/work/tempmeas.htm": in 3 ms I can get about 2.7
kV higher charging voltage by bypassing the inductive filter. That's a gain of
about 20%.
At least in my case, this probably means that I have better to convert my HF
filter (2 inductors on 2 toroids) into a common mode choke (2 winding on the
same toroid). By the way, the filter (cores) gets slightly warm so that I am
really loosing some power in there.
2. Reduced performance after warm-up
---------------------------------------------------------
I reduced the RSG gaps from 4 to 2 (bypassed an electrode couple) and measured
again: again reduced performance! Then I waited until the spark length was
really badly crippled: at about 0.5 m length I took a snapshot (original length
was 2.5 m that in 20 seconds got reduced to 0.5 m). Then I superimposed one
snapshot taken at full performance and you can see the result in picture #10
(same web page). The charging speed slows down!
This means that (picture #5) the RSG bang missing is only due to the slower
charging that results in lower capacitor voltage at electrode presentation
time.
So the RSG keeps the same threshold voltage, simply the SMPS doesn't make it
anymore to get to it in time.
Sad story...
Regards