KYORITSU 3147A - Manual (Page 15)

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This function allows electric charges stored in the capacitance of
the circuit under test to be automatically discharged after
testing.Discharge can be monitored by the AC voltage reading.
(6) Set the Range switch to the OFF position, and disconnect the
probes from the instrument.
6−3 Continuous measurement
For continuous measurement, a lock-down feature is
incorporated on the Test button. Pressing and turning clockwise
locks the button in the operating position, the button is released
by turning it counterclockwise.
Nominal voltage
0.05
MΩ
50V
0.1
MΩ
100V
0.125
MΩ
125V
0.25
MΩ
250V
0.5
MΩ
500V
Lower limit of insulation
resistance to supply
nominal current ( 1mA )
DANGER
While the Test button is locked down, a high voltage is present
at the tip of a probe. Attention should be paid to avoid possible
shock hazard.
6−4 Output voltage characteristics
This instrument conforms to IEC61557. This standard defines
that the nominal current shall be at least 1mA, and the lower
limit of the insulation resistance maintaining the nominal voltage
at the measurement terminal. (See the graph below.)
This value is calculated by dividing the nominal voltage by
nominal current. i.e., in case that the nominal voltage is 500V,
the lower limit of the insulation resistance is found as follows.
Divide 500V by 1mA equals 0.5MΩ
That is, insulation resistance of 0.5MΩ or more is required
toprovide the nominal voltage to the instrument.