MOTs & Thoughts

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "S & J Young by way of Terry Fritz <twftesla-at-qwest-dot-net>" <youngs-at-konnections-dot-net>

I took some no load measurements on a 4 MOT stack that some of you might
find interesting.  All 4 MOT primaries are in parallel, and are powered by a
120 volt variac.  Here are no load primary volt vs amp measurements:

Volts                    Amps
below 75              less than .5
 80                         1
 95                         2
 90                         3
 95                         4
100                        5.5
105                        7.5
110                      10.5
115                      14.5
118 (max)           17.6

As you can see, the MOT cores start serious core saturation at around 100
volts, or about 85% of their rated voltage.  The moral of this story is to
design your MOT stacks to produce the output you need without exceeding 85
or 90% of the normal primary voltage.

Question:  Suppose I knock out the magnetic shunts.  Would the above
measurements be much different??

Another thing to be aware of is that above 90% of normal input voltage
causes significantly distorted sine waveforms that sometimes have strange
effects on DVMs, causing them to indicate quite inaccurate measurements.

--Steve Young