Hitachi RAS-25QH1 Technische Information Seite 179

< During start current control>
@ itis required to maintain the start current (DC current) constant to smooth the start of the DC motor for
the compressor. ,
@ The RAM-80QH1 uses software to control the start current.
@ The start current varies when the supply voltage varies. This contro! method copes with variations in
the voltage as follows.
(1)
(2)
Turns on the power module's U* and V" transistors so the current flows to the motor windings as
shown in Fig. 9-9.
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. 8A as shown in Fig. 9-10.
Power module
DC current
Compressor motor
DC 380V
Chopper duty: high
| DC voltage: low
DC voltage: 380V
DC voltage: high
W transistor
ON-time
DC voltage (start current)
Set value
DC current (A)
(Speen a ree S Time
Fig. 9-10
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