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RE: Resistive Loads Poor Choice was: HV MMC



Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

At 03:16 PM 4/16/2003 -0600, you wrote:
>Original poster: "Mccauley, Daniel H by way of Terry Fritz 
><teslalist-at-qwest-dot-net>" <daniel.h.mccauley-at-lmco-dot-com>
>
>
>The problem with resistive dummy loads is that they never really represent
>load conditions which will really
>be used in practice.  For example, if you were designing a power supply for
>use with tesla coiling, or any other
>type pulsed load condition, a resistive load would be an extremely poor
>choice.


I think that Terry was looking at this as an example of a construction 
technique for a HV MMC (i.e. series string of 100 or so 2kV capacitors to 
make a 200 kV cap), rather than constructing HV loads.





>One example is that we use a 45kW switching power supply (45kV) for a radar
>transmitter system.  The vendor tested these things quite thoroughly using
>resistive loads.  However, once the supplies were installed in a transmitter
>system, they would burn up within seconds.  After burning a dozen or so
>supplies like this, our company finally put a half-million bucks out to
>design a high power pulse-load which was then sent to the power supply
>vendor.


Indeed, we build test loads for pulse HV power supplies intended to drive 
TWTs and EIKs here at JPL.  Of course, the ultimate dynamic test load is a 
sample tube, since replicating all aspects of the load impedances with some 
form of circuitry is tricky.