IVT 12KHR-N Service Manual page 17

• Power ON/OFF
• Automatic operation mode setting
• Swing louvre
• Plasmacluster mode
1.25.2 Setting not memorized
• Timer setting
2. Explanation of cluster circuit
The cluster unit generates cluster ions, which are circulated throughout the room by the air flow created by the blower fan (indoor unit fan motor) in
the air to air heat pump unit.
1) When microcomputer output turns "H," the IC13 output changes to "Lo," turning ON the SSR1 and applying 100 V to the cluster unit for the gener-
ation of cluster ions (positive and negative ions).
AC230V
Microcomputer output
3. Outline of PAM circuit
3.1. PAM (Pulse Amplitude Modulation)
The PAM circuit varies the compressor drive voltage and controls the rotation speed of the compressor.
The IGBT shown in the block diagram charges the energy (electromotive force) generated by the reactor to the electrolytic capacitor for the inverter
by turning ON and OFF.
AC
230V
When the IGBT is ON, an electric current flows to the IGBT via the reactor (L5) and diode bridge (DB2).
When the IGBT turns OFF, the energy stored while the IGBT was ON is charged to the voltage doubler capacitor via the diode bridge (DB1).
As such, by varying the ON/OFF duty of the IGBT, the output voltage is varied.
R17
R19
IC13
R18
Reactor L5
Noise
filter
AC clock
detection
circuit
[PAM drive circuit]
PAM drive circuit block diagram
• Full power setting
• Internal cleaning
1.25.3 Disabling auto restart function
By removing (cutting) jumper 8 (JP8) on the printed circuit board
(PCB), the auto restart function can be disabled.
12V
SSR1
R16
DB1
+
DB2
IGBT
drive
circuit
IGBT
Microcomputer (IC1)
2 – 13
Cluster unit
5 4
C5
1 1
6 4
2 1
IPM
Compressor
Overvoltage
Compressor
detection
position
circuit
detector
12KHR-N