188.8.131.52 ACRT Test
The accuracy for the test voltage is given by:
AT = AR + AV + AC + AI + ARNG
AT is the total accuracy (%)
AC is the calibration accuracy (%)
AI is the correction for current level (%)
AV = 3% +10/VM %
AC = 0.03%
AI = 0.003% /IM
ARNG= Range/VM %
IM is the maximum test current (A (rms.))
VM is the actual voltage (V(rms.))
Range is the voltage range used for the measurement that will be the lowest possible of the following ranges:
The value of AR is given in the table in section 1.1. of this chapter.
Under certain test conditions the measured current will be higher than the allowed minimum limit due to parasitic effects on the AT3600 and any connected fixture system. The maximum parasitic effect created by the AT3600 with every node being used on an ACRT test can be calculated by:
Ip = V*(4.614*10-10 + 9.1*10-11*f) where V = Test voltage and f = test frequency.
This works out to be 12.5uA at 2.5KV@50Hz.