45
12-1. Measurement of Insulation
Resistance
●
The insulation is in good condition if the resistance
exceeds 2M
½
.
12-1-1. Power Supply Wires
Clamp the grounding terminal of the power plug with
the lead clip of the insulation resistance tester and
measure the resistance by placing a probe on either
of the power wires. (Fig. 1)
Then measure the resistance between the ground
wire and other power wire. (Fig. 1)
12-1-2. Indoor Unit
Clamp an aluminum plate fin or copper tube with the
lead clip of the insulation resistance tester and mea-
sure the resistance by placing a probe on each termi-
nal screw except where the ground line is connected
on the terminal plate. (Fig. 2)
12-1-3. Outdoor Unit
Clamp a metallic part of the unit with the lead clip of
the insulation resistance tester and measure the resis-
tance by placing a probe on each terminal screw
where power supply lines are connected on the termi-
nal plate. (Fig. 2)
12-1-4. Measurement of Insulation
Resistance for Electrical Parts
Disconnect the lead wires of the desired electric part
from terminal plate, capacitor, etc. Similarly discon-
nect the connector. Then measure the insulation
resistance. (Figs. 3 and 4)
Refer to Electric Wiring Diagram.
If the probe cannot enter the poles because the hole
is too narrow then use a probe with a thinner pin.
NOTE
Insulation
tester
Probe
Clip
Ground wire
Fig. 1
Terminal plate
Copper
tube or
metallic part
Clip
Insulation
tester
Probe
Fig. 2
Copper
tube or
metallic part
Clip
Insulation
tester
Probe
Fig. 3
Clip
Insulation
tester
Probe
Metallic
part
From fan motor,
compressor and
other parts
Fig. 4
12. CHECKING ELECTRICAL COMPONENTS
