"Calibration" of the Pratt High Current Transformer
       -------------------------------------------------------

                                                 Original Rev.  27-AUG-1997
                                                   Latest Rev.  27-AUG-1997



                         Fluke 8060A                            E-Shop
  Voltage Across      on its 2000 mA Range       AmpProbe       Variac
  a Good 4 Wire      looking at the Toroid      Clip On AC     Primary
  0.1 mOhm Shunt      Current Transformer     Current Meter    Current
  --------------     ---------------------    -------------    -------
       17.0 mV                134 ma              15 Amps        - Amps
       30.4                   237                 27             -
       40.5                   316                 36            1.0
       52.2                   407                 47            1.5
       74.1                   578                 64            2.0
       94.8                   742                 82            2.4
      101.8                   794                 86            2.5
      127.7                   998                115            3.0
      152.2                  1193                135            3.5
      167.3                  1309                145            3.8
      181.5                  1423                160            4.2
      197.5                  1543                170            4.6
      213.0                  1668                185            5.1


Notes:

   The load resistor was fixed at about 0.012 Ohms.  This is the lowest
   that our "Toaster Load Box" will go.

   The voltage across the "good" 4 wire  0.1 mOhm  resistor is assumed to
   correctly represent the current through the load.

   The Fluke 8060A was left on its 2000 mA AC current scale for all tests.
   The is reading the current in the secondary of the home made toroid
   transformer.

   The AmpProbe clip on AC current meter was set at the appropriate
   range for each test (40, 100, 300 Amps)

   The "E-Shop Variac Box" shows an approximate reading of the current
   in the primary of the heater transformer.  It was used to look for
   any indication of saturation.



Safety Notes:

   If the Banana plugs on the secondary of the home made toroid transformer
   are not connected to a short circuit (e.g. a current meter) then spikes
   of up to about 100 Volts will appear between the two banana terminals.

   Make sure that the current fuse in the Fluke 8060A is not blown  (as
   they normally are).