Megohmmeter Model - AEMC 5070 User Manual

When measuring high levels of insulation (>1GΩ), it is advisable to use the "G"
guard terminal to eliminate the influence of surface leakage currents. The guard is
connected between the two measurement contact points, and the surface suscep-
tible to surface currents, (e.g. dusty, damp cable or transformer insulation). In this
case, alligator clips are preferable to hand-held test probes.
As soon as the insulation measurement is stopped, the test circuit is automatically
discharged using the instrument's internal discharge feature.
Connection diagram for measurement of high resistance insulation
a) Example of a motor (reduction of capacitive effects)
BLUE
RED
+
BLACK
M
G
-
BLUE
JUMPER
b) Example of a cable (reduction of superficial leak effects)
RED
Braid
External insulator
Insulator
+
Cable
G
BLUE
Guard
-
BLACK
BLUE
JUMPER
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Megohmmeter Model 5070