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Megohmmeter Model 6505 - User Manual
3.4 INSULATION MEASUREMENT
Depending on the type of measurement, there are three ways to connect the
instrument.
In all cases, disconnect the device to be tested from the source.
Weak Insulation
Connect the red high-voltage
lead between earth and the
+
terminal of the instrument.
Connect the black high-voltage
lead between one phase of the
motor and the
-
terminal of the
instrument.
M
+
-
Strong Insulation
For a very high insulation value,
connect the small blue high-
voltage lead between the rear
earth pick-up jack of the black
lead and the
G
terminal of the
instrument.
This serves to reduce any
external influence and obtain a
more stable measurement.
M
G
+
-
Cable
Connect the red high-voltage
lead between the braid and the
+
terminal of the instrument.
Connect the black high-voltage
lead between the core and the
-
terminal of the instrument.
G
+
-
Connect the blue high-voltage lead between the insulation and the
G
terminal of
the instrument.
The guard serves to eliminate the effect of surface leakage currents.
