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SRSG current measurement



Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi All,

Just to test "things", I hooked up all my trusty AC current measurement
toys to my small coil's Sync Rotary Spark Gap motor just to see how close
they would all read and make sure nothing was broken.

http://hot-streamer-dot-com/temp/SRSGCurrent.jpg

The HP 34401a and 34330A current shunt give 4.567 amps.  They should be
within 0.4%.

My Greenlee CM-650 current meter gives 4.7 amps (probably 0.1 amp high
since it likes to have a 0.1 amp offset).

My Metex 4650CR gives 4.517 amps.

The Pearson 411 Current monitor and Tek 3012 scope give 4.53 amps.

I then hooked up the old Micronta 22-185 Radio Shack meter and got 4.51 amps.

All are true RMS meters except the Radio Shack.  The waveform is pretty
well behaved so it worked well too.

Nothing really surprising here but i just thought I would report that
practically any meter will work for sync gap motor current measurement.  I
do note that "true" accuracy is directly proportional to the cost of the
equipment, but not a big deal for most work.  I like the "true RMS" meters
far better for most coil work and I think they are definitely worth the
extra cost.

Cheers,

	Terry