– 60 –
DC voltage : Low
DC current : High
DC voltage : High
DC current : Low
DC voltage : 260V
Rotation speed
DC current
0
0
IPM
DC current
P
DC
Voltage
N
Detection
resistor
U+
V+
W+
U
−
V
−
W
−
U
V
W
Compressor motor
Fig. 6-5
Fig. 6-6
(3) Start current control
R003,R004,R608,R613, detect the DC voltage at the power circuit. The microcomputer receives a
DC voltage and applies correction to the overload set value so the DC current will be low when the
DC voltage is high.
(Since the load level is indicated by the DC voltage multiplied by DC current, R247, R248, R249 are
provided to perform the same overload judgement even when the voltage varies.)
It is required to maintain the start current (DC current) constant to smooth the start of the DC motor
of the compressor.
RAC-
18YH4
uses software to control the start current.
The start current varies when the supply voltage varies. This control method copes with variations
in the voltages as follows.
(1) Turns on the power module’s U
+
and V- transistors so the current flows to the motor windings
as shown in Fig. 6-6.
(2) Varies the turn-ON time of the W
+
transistor according to the DC voltage level and the start
is controlled so the start current is approx. 10A .
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 ...
