– 89 –
60
Fig. 8-6
Fig. 8-7
Voltage at microcomputer pin
Rotation speed of compressor
Deceleration DecelerationAcceleration Acceleration
Commanded rotation speed
Actual rotation speed
59
61
58
+
60
Is
D104
L
CT1
N
R005
0V0V
0V
0V
0V0V
7
42R
600R
501C
+
712C
900C
R222
C218
R221
R248IC4
+
6
5
7
Is
Id
Vd
CN13
CN14
R24
N1
DC 260-380V
SPM2
MAIN P.W.B.
P2
Direct Current
DC Current
Detection Resistor
HIC
IC1
Microcomputer
5
02
D
4
02
D
422C
0V
222C
0V0V
5V
5V
35
2
R
942R
005R
+
C205
0V
5
1
373938
R245
10
1
. Voltage amp. circuit
●
The voltage amp. circuit amplifies the DC current level detected by the detection resistor after being
converted to a voltage and supplies it to the microcomputer. 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 generated
from the DC current flowing to the detection resistor, and supplies it to IC4 pin 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
2
5
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