Subaru Robin RGD3300H - Manual (Page 12)

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4-3 GENERATOR OPERATION
4-3-1 GENERATION OF NO-LOAD VOLTAGE
(1) When the generator starts running, the permanent magnet built-in to the rotor generates 3 to 6 V of
AC voltage in the main coil and condenser coil wound on the stator.
(2) As two condensers are connected to the condenser coil, the small voltage at the condenser coil
generates a minute current
which flows through the condenser coil. At this time, a small flux is
produced with which the magnetic force at the rotor’s magnetic pole is intensified. When this mag-
netic force is intensified, the respective voltages in the main coil and condenser coil rise up. As the
current
increases, the magnetic flux at the rotor’s magnetic pole increases further. Thus the volt-
ages at the main coil and condenser coil keep rising by repeating this process.
(3) As AC current flows through the condenser coil, the density of magnetic flux in the rotor changes.
This change of magnetic flux induces AC voltage in the field coil, and the diode rectifier in the field
coil circuit rectifies this AC voltage into DC. Thus a DC current flows through the field coil and mag-
netizes the rotor core to generate an output voltage in the main coil.
(4) When generator speed reaches 3000 to 3300 rpm (60 Hz type), the current in the condenser coil
and field coil increases rapidly.
This acts to stabilize the output voltage of each coils. If generator speed further increases to the
rated value, the generator output voltage will reach to the rated value.
4-3-2 VOLTAGE FLUCTUATIONS UNDER LOAD
When the output current flows through the main coil to the appliance, a magnetic flux is produced and
serves to increase current in the condenser coil. When current increases, the density of magnetic
flux across the rotor core rises. As a result, the current flowing in the field coil increases and the generator
output voltage is prevented from decreasing.
ROTOR
DIODE
FIELD COIL
SURGE
ABSORBER
PERMANENT MAGNET
FOR INITIAL EXCITATION
STATOR MAIN COIL
RECEPTACLE
APPLIANCE
CONDENSER
CONDENSER COIL
a
a
c
a a
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