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(RAS-40QH1) |
@ Fig. 9-2 shows the indoor DC fan motor drive circuit.
Micro computer
Bln)
EM)
al BLU
xe
Indoor DC
N10
fan motor
Divided
output
Fan motor
current G9
detection
Fig. 9-2
@ The circuit produces the fan motor drive voltages, 8-33V, from 35V DC supplied from the outdoor unit and
controls the fan motor speed.
© (903 is switched on and off according to the signal at fan PWM output pin 67 to control the voltage which
is smoothed by D901, L901 and C901 to drive the fan motor.
@ The output voltage is divided by R901 and R903 and is input to divided voltage output pin ©; the micro
computer controls the fan PWM
output so the output voltage is set to the specified value.
The chopper
frequency of the fan PWM
output is 15.7kHz.
@ The fan current abnormality detector detects the fan motor current using R906-R915 and COM801
determines
an overcurrent and outputs it to fan current abnormality pin 69 which is "Hi" during normal operation and
"Lo" when overcurrent occurs.
@ REG3 supplies 5V DC to the DC fan motor.
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