AYXP26FRN
2 – 14
3.2.3 IGBT ON start time (delay time B)
• Based on the zero-cross of the AC voltage, the IGBT turns ON after a delay time set according to the power source frequency.
3.2.4 IGBT ON time (C)
• After the above delay time, the IGBT turns ON to supply a current to the reactor.
• The ON time of the IGBT determines the amount of energy (level of DC voltage rise) supplied to the reactor.
DC voltage level in each operation mode (varies depending on external load conditions)
– Cooling operation --- 220 to 240 V
– Heating operation --- 220 to 280 V
3.3. PAM protection circuit
To prevent excessive voltage of PAM output from
damaging the IPM and electrolytic capacitor as well
as the control printed circuit board (PCB), this circuit
monitors the PAM output voltage and turns off the
PAM control signal and PAM drive immediately
when an abnormal voltage output is generated. At
the same time, it shuts off the compressor operation.
The PAM output voltage is distributed to pin (4) of
the comparator (IC8). If this voltage exceeds the ref-
erence voltage at pin (5) of the IC8, the output of the
comparator (IC8) reverses (from H to L) and it is
input to pin (38) of the microcomputer (IC1) to halt
the PAM drive.
The protection voltage level is as follows.
– Overvoltage --- 350 V or higher
3.3.1 Details of troubleshooting procedure for PAM
1) PAM shutdown due to error
1) When the DC voltage detection circuit sends a signal exceeding the specified voltage to the microcomputer
DC voltage of 400 V or higher (detection circuit input voltage of about 8.4 V or higher) [IC8 pin (4)]
– When an error is detected
• PAM IGBT turns OFF.
• Compressor turns OFF.
• All units shut down completely when the error occurs four times.
2) When the outdoor unit clock waveform differs from the specified value immediately before the PAM IGBT turns ON
When there is no clock waveform input
When a clock signal of other than specified power source frequency is input
– When an error is detected
• PAM IGBT does not turn ON.
• Compressor operates normally.
• Complete shutdown does not occur.
2) PAM error indication
In case of error "1)"
– An error signal is sent to the indoor unit as soon as an error is generated.
• Malfunction No. 14-0 is indicated when the error code is called out by the indoor unit's self-diagnosis function.
– The LED on the outdoor unit flashes 14 times when an error is generated.
• The LED continues flashing in the 14-time cycle even after the compressor stops operating.
• The LED turns off (data is deleted from the memory) when the outdoor unit power is turned off.
In case of error "2)"
– An error signal is sent to the indoor unit as soon as an error is judged.
• Malfunction No. 14-1 is indicated when the error code is called out by the indoor unit's self-diagnosis function.
– The LED on the outdoor unit flashes 14 times when an error is judged.
• The LED on the outdoor unit flashes in normal pattern when the compressor stops operating.
(Compressor OFF or Thermostat OFF from remote control)
* When a user complains that the air conditioner does not provide sufficient cool air or warm air
R2
255K
C10C9
420V
750uF
R5
300K
R7
23.7KF
R6
23.7KF
0V
0V
0V
IC8
15V
R113
19.1KF
R112
15K
5V
R114
1M
R116
1K
5
4
2
(Overvoltage detection)
During abnormal voltage output
IC1
38
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