Hitachi RAD-25NH7 Service Manual page 52

(3) Smoothing capacitor (C501, C502, C503)
This smoothes (averages) the voltage rectified by the diode stacks.
<Notes> Smoothing capacitor C501 is not available for model RAC-25NH5 and RAC-35NH5.
a
b
DC voltage
Vd
(approx. 260-360V during operation)
(4) Smoothing capacitor (C010, C011)
This smoothes (averages) the voltage rectified by the diode
stack2. A DC voltage is generated in the same way as in
Fig. 1-3.
Voltage between + side of C010 and – side of C011 is about
330V.
(5) C001 to C003, C012 to C015, C007, C008, NF COIL1, COIL,
absorb electrical noise generated during operation of
compressor, and also absorb external noise entering from
power line to protect electronic parts.
(6) Surge absorber, Varistor 1, 2, 3,
absorbs external power surge.
(7) Inrush protective resistor (R007, R008)
This works to protect from overcurrent when power is turned
on.
Smoothing Capacitors
SPM2
OV
OV
OV
Fig. 1-3
Fig. 1-2
Be careful to avoid an electric shock as a
G
high voltage is generated. Also take care
not to cause a short-circuit through incorrect
connection of test equipment terminals. The
circuit board could be damaged.
< Reference >
When inrush protective resistor is
G
defective,
malfunction. As a result, DC voltage
is not generated and no operation can
be done.
– 62 –
diode stack may