YOKOGAWA WT200 User Manual page 222

15.2 Calibration
15-8
Preparation
Set the frequency of the AC voltage standard and of each channel of the synchronizer to
60 Hz. Then, while not exceeding the maximum values of the external synchronization
inputs of the voltage and current standard, rise the output level of the synchronizer until
the standards are synchronized. Make sure that the phase angle between each channel
of the synchronizer is 0 degrees.
Calibrating
1. Set the voltage or current range of this instrument to the range to be calibrated.
2. Set the output voltage of the AC voltage standard to the rated range of this
instrument, and output the voltage.
3. Set the output current of the AC current standard to the rated range of this
instrument, and output the current.
4. Fine adjust the output values of the standard so that the displayed voltage or
current value on this instrument show the rated range.
5. Read the output voltage or current value, and keep it as a reference.
6. Verify that the displayed power value corresponds to the rated value. The
product of the voltage value and the current value is the reference value of the
power.
Note
• Before starting the above described calibration, verify that the accuracy of this instrument lies
within the specifications.
- Adjust the output of the standard to the rated range value of this instrument, then read the
displayed voltage or current value on this instrument and verify that this value lies within
the specifications.
- Slightly change the phase angle of ch2 of the synchronizer (current signal) so that the
displayed power value becomes the rated value. Then read the displayed power value on
this instrument and verify that this value lies within the specifications (power factor = 1).
- Change the phase of ch2 of the synchronizer so that the displayed power value becomes
zero. Then read the displayed power value on this instrument and verify that this value lies
within the specifications (power factor = 0).
• When calibrating the harmonic analysis, match the phase so that the displayed power value
becomes the calibrated value.
• When calibrating using a frequency of more than 60 Hz, set the same frequency for the
synchronizer and the standard. In such a case, use a voltage/current standard which surely
has a sufficient accuracy regarding the output frequency. This means to use measuring
equipment with an accuracy of 3 to 4 times the specified higher accuracy of this instrument.
IM 253421-01E