KYORITSU 3128 - Manual (Page 61)

KEW3128
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KEW3128 6. Measurement
6. 6 DD Measurement (Dielectric Discharge)
6.6.1 Dielectric Discharge
DD : Dielectric Discharge
This measurement method is usually used to diagnosis multi-layer
insulations, which requires the instrument to measure the discharge current
and capacitance of the measured object 1 min after the removal of the
test voltage. This is a very good diagnostic insulation test that allows
deterioration and other problems voids in the multiple insulations to be
assessed.
Dielectric
Discharge
=
Current value 1 min after
completing measurement (mA)
Voltage value when a measurement
complete x Capacitance (F)
DD 2.0 or less 2.0 ～ 4.0 4.0 ～ 7.0 7.0 or more
Criteria Good Warning Poor Very Poor
This criteria is a guide and could be slightly changed and be adapted to
particular objects under test based on practical experience of the users.
This method has been established to test high voltage generators installed
in electric power plants in the Europe countries.