Power Module Circuit - Hitachi RAS-18FH6 Service Manual

+ –
Fig. 3-4 Power module circuit (U is OFF, V is ON)
+ –
Since current flows at point B only when U transistor and V transistor are ON, the current waveform
at point B becomes intermittent waveform as shown in Fig. 3-3. Since current at point B is approximately
proportional to the input current of the air conditioner, input current is controlled by using DC current
(Id) detection resistor.
<Reference>
If power module is defected, self diagnosis lamps on the MAIN P.W.B. may indicate as shown below:
Table 3-1
LD303
MAIN P.W.B.
LD302
LD301
SERVICE SWITCH
IPM
HIC
Fig. 3-5
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