RE: NST Charging Circuit Study

["John H. Couture" <couturejh-at-worldnet.att-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Terry -

Note that to get the right answers you will need to set up MicroSim to use
the trig functions. The actual line side currents would have to be known.
This would give you the volt amps. The secondary volts and amps would give
you the watts. You could then easily determine the VAR.

John Couture

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-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Tuesday, September 05, 2000 5:03 PM
To: tesla-at-pupman-dot-com
Subject: NST Charging Circuit Study


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

Hi All,

	With all the recent talk of cap sizes, PFC caps, and break rates it would
not be that hard just to crunch through all the variables in MicroSim and
just come up with a set of tables.  However, I don't have all the
transformer data.

I need to know three things to model an NST:

1.	Primary DC resistance.
2. 	Secondary DC resistance.
3.	Open load AC current draw at rated input voltage.

The NST transformers that I need this data for are:

15/30
12/60
12/30
9/60
and any others that people may have a use for.

The resistances can be found with just about any ohmmeter.  The input
resistance will probably be very low but close is fine.

For the AC measurement, you will probably want to turn the voltage up and
down slowly with a variac.  Just switching an NST on suddenly may cause a
current surge that will pop the fuse in the multimeter.  Of course, beware
the output voltage.  There must be nothing at all connected to the output
terminals for this test.

If anyone would like to take this data or you already know it, please send
the info to:

terrellf-at-uswest-dot-net

Do be very careful of the high voltage and AC voltage on the third test!!

Thanks a bunch!,

	Terry