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6. CHECKING ELECTRICAL COMPONENTS
6-1 Measurement of Insulation
Resistance
The insulation is in good condition if the
resistance exceeds 1MΩ
6-1-1. Power supply wires
Clamp the grounding terminal of the power plug
with a lead clip of the insulation resistance tester
and measure the resistance by placing a probe
on both the two power terminals. (fig.1)
Then, also measure the resistance between the
grounding and other power terminals. (fig.1)
6-1-2. Indoor Unit
Clamp a metallic part of the unit with the lead
clip of the insulation resistance tester and measure
the resistance by placing a probe on each terminal
screw where power supply lines are connected on the
terminal plate. (fig.2)
6-1-3. Outdoor Unit
Clamp an aluminium plate fin or copper tube with
the lead clip of the insulation resistance tester
and measure the resistance by placing a probe
on each terminal screw on the terminal plate. (fig.2)
Note that the ground line terminal should be skipped
for the check.
6-1-4. Measurement of Insulation
Resistance for Electrical Parts
Disconnect the lead wires of the desired electric
part from terminal plate, capacitor, etc.
Similary disconnect the connector.
Then measure the insulation resistance. (fig.3 and 4)
NOTE: 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.
power plug
(Local supply)
probe
NOTE
The shape of the power plug may differ from that
of the air conditioner which you are servicing.
Clip
Copper
tube or
metallic part
Clip
Copper
tube or
metallic part
Metallic
part
Clip
57
Ground
Insulation
tester
Terminal plate
Insulation
tester
Probe
Insulation
tester
From fan motor,
compressor and
other parts
Probe
Insulation
tester
Fig. 1
Probe
Fig. 2
Fig. 3
Fig. 4
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