– 59 –
The voltage amp. circuit amplifies the DC current level detected by the detection transformer CT1.
Receiving this, the microcomputer converts it to a digital signal and compares it with the internal
data to judge whether or not overload control is required.
< During overload control >
The filter consisting of R245 and C217 removes high harmonic components from the voltage generate
from the DC current flowing to the detection resistor, and supplies it to IC4 pin 5 . IC4 forms a non-
inverting voltage amp. circuit together with the peripheral elements.
The microcomputer stores the set values which vary according to the rotation speed. When the DC
current level exceeds the set value, the microcomputer enters the overload control state.
The set Value is determined by the amplification of the voltage amp. circuit
Amplification : high
→
DC current : low
Amplification : low
→
DC current: high
Fig. 6-4
Fig. 6-2
(2) ID OVL
Fig. 6-2. The filter consisting of R245 and C217 removes high harmonic frequencies from the voltage
generated by the current flowing to Detection resistor; R245 and C217 average the voltage. This
compares this input with the set value, and if the input exceeds the set value, it enters overload
control status.
the set value, the microcomputer decreases the rotation speed of the compressor and reduces the
load.
Fig. 6-3
(1) IS OVL
voltage is then input to IC4 pin 5 and supplied to microcomputer pin 60 . The microcomputer
Fig. 6-3 shows the rotation speed control. When the voltage at pin 60 of the microcomputer exceeds
Judgment value according to rotation speed
(internal judgment value)
Rotation speed
DC current
Decelerating
Accelerating
Accelerating
Actual rotation speed
Command rotation speed
Decelerating
Voltage at microcomputer pin
^1
Rotation speed of compressor
−
IPM
−
11
42
R003
R004
R514
R513
P
29
32
35
37
0V
Q501
R613
R612
0V
0V
R906
R905
C919
N
5V
0V
0V
V d
I p
I d
I S
Reset
Reset output
Microcomputer
Main P.W.B.
0V
R252
R288
IC5
1
2
3 +
0V
5V
C215
R289
D208
R287
C204
R285
C226
R292
R284
R286
0V 0V 0V
12V
0V
R222
CN4A
CN4B
R221
C010
D204
C218
C224
C210
0V
0V
R248
IC4
7
6
5 +
R249
R241
R608
C222
D204
5V
0V
5V
0V
0V
R245
+
C217
R247
+
R005
D001
0V
0V
0V
0V
CT1
C009
R006
Power P.W.B.
Detection
Resistor
59
17
60
61
56
48
1
DC Current
Direct Current
Main P.W.B.
Summary of Contents for RAC-18YH4
Page 21: ... 19 GRAM 18YH4 RAC 18YH4 CAUTION The marked parts are very important ones for safety ...
Page 23: ... 21 RAS 18YH4 MODEL ...
Page 24: ... 23 RAC 18YH4 MODEL Ｈ８ ３ ０ ３ ９ ＡＸ ８ Ｔ １ ０ ...
Page 27: ... 26 MAIN P W B MARKING ON P W B COMPONENT SIDE SOLDERING SIDE MODEL RAC 18YH4 ...
Page 29: ... 29 button MODEL RAS 18YH4 BASIC MODE 31 33 33 33 37 35 ...
Page 35: ... 38 REFRIGERATING CYCLE DIAGRAM MODEL RAS 18YH4 RAC 18YH4 SUCTION TANK SUCTION TANK ...
Page 99: ...Printed in Japan TSK AW NO 0004E RAS 18YH4 RAC 18YH4 ...
