Amperes. Therefore, the theoretical output Current from the transducer would be 5
Amperes, if the transducer output current is 20 milliampere. For this example, let's say
that the measured MPRT output current is 5.001.
For this example, let's say that the measured output current from the transducer is
19.9991 mAmperes. Based on a Max. value of 20 mA equals 5 Amperes, the displayed
AC Amperes
in the
Transducer Output
section of the
Transducer Test Screen
should
read
4.9997 Amperes
If, 20 mA = 5 Amperes or 0.25 A / 1 mA
.
Then, 19.99 mA * 0.25 A/mA = 4.9975 Amperes
The
Accuracy
displayed in the
Transducer Output
section would be equal to the
following,
(4.9975 - 5.001 / 5.001) * 100 = % accuracy or
-0.0699
%
If this were a 0.15 % transducer, then the firmware would compare the accuracy values
between the Setting Screen and the Test Screen and would display
PASS
in the
Transducer Output
section of the test screen..
Note: All of the calculations are very similar when testing DC Current
transducers.
3.8.10.8.3
Frequency Transducers
The frequency transducer requires 1 voltage output channel to test. The MPRT will
automatically select the first voltage channel available,
V1
. The test will initially start at
the default value voltage and frequency that is set in the
Default Setting Screen
. For
example, 120 Volts L-N, 60.0000 Hz. When the user inputs the
MAX.
Frequency value in
the
Transducer Setting Screen
, the firmware will calculate the required test frequency
for full scale value.
Example: The default frequency is 60.00, and the user inputs 65 Hz as Max. Value.
Therefore, when the user inputs 65 Hz in the
MAX
. value window, the test set should
automatically show a test frequency value of 65 Hz at the default voltage value of 120
Volts.
When the test is Started, the measured voltage and frequency outputs are displayed. The
MPRT output frequency is the value that gets displayed in the
Transducer Test Screen
under the
MPRT Output
, next to the Label of
Output Frequency
Another value of
Frequency gets calculated using the measured dc Volts or dc milliampere output as
displayed in the
Transducer Output
section. Let us assume that in our example
transducer, the output is in dc Volts. For this example, let us say that 10 DC Volts is
equal to the full scale output of 65 Hz. Therefore, the theoretical output Frequency from
the transducer would be 65 Hz, if the transducer output voltage is 10 Volts DC. For this
example, let's say that the measured MPRT output frequency is 65.00 Hz., and the
measured transducer output voltage is 10.001 Volts. The measured transducer output
Frequency would be,
If, 65.00 Hz = 10 Volts DC
Then, 65/10 = 6.5 Hz/V
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