SR 4 GENERATOR
SYSTEMS OPERATION
RADIO FREQUENCY INTERFERENCE (RFI)
SUPPRESSION
When controlled rectifier (CR9) "turns on", it is very
rapid (approximately three microseconds). This causes
a shock load on the stator (L6). AC voltage shocks till
cause harmonics (frequency multiplications) at radio
frequencies. For many applications, these harmonics
will cause electronic equipment to operate very badly.
The action of suppression capacitor (C2) and SCR
reactor (L2) gives a reduction of the shock load on stator
(L6). As said earlier, suppression capacitor (C2) gets a
charge during the time (T0) is positive and (T8) is
negative and controlled rectifier (CR9) is not "turned on".
When a gate signal is sent to controlled rectifier (CR9)
the first surge of current is caused by the voltage charge
on (C2). The current increase time is made longer by
SCR reactor (L2). Suppression reactor (L1) and RFI
suppression capacitors (C1) and (C3) cause a reduction
of interference with radio frequencies. Damping Resistor
(R5) is connected in parallel with suppression reactor
(L1) to prevent any voltage oscillations that start in (L1).
RFI suppression capacitor (C1) is connected from
neutral to (T8) on phase 2 of stator (L6). Suppression
capacitor (C3) is connected from neutral to generator
frame ground. To get the maximum effect from the RFI
suppression capacitors, the generator frame must be
connected to an earth or building (station) ground.
GENERATOR REGULATOR ASSEMBLY
C1,3
RFI Suppression capacitors
C2
Suppression capacitor
CR9
Controlled rectifier
L1
Suppression reactor
L2
SCR Reactor
R5
Damping resistor
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