Hitachi RAS-E10H2 Service Manual page 47

Since current flows at point B only when U
point B becomes intermittent waveform as shown in Fig.3-3. Since current at point B is approximately point B
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:
LD303
MAIN P.W.B.
LD302
LD301
IPM
HIC
Fig. 3-5
Fig. 3-4 Power module circuit (U
+ transistor and V
SERVICE SWITCH
+ – – –
is OFF, V is ON) is ON)
transistor is ON, the current transistor is ON, the current
– – –
Table 3-1
Self-diagnosis
Ip (peak current cut)
Abnormal low speed
rotation
Switching incomplete
- 51 -
waveform at
y using DC current (Id) y
Self-diagnosis lamp
and mode
Blinks 2
LD301
times
Blinks 3
LD301
times
Blinks 4
LD301
times