SR 4 GENERATOR
SYSTEMS OPERATION
C PROTECTION OF GENERATOR CIRCUITS
The SR 4 Generator regulator and excitation circuits
use many components for protection. Fuse (F1) is the
type that opens very rapidly and gives protection against
secondary damage caused by another component
failure. This type of fuse is used because it is
specifically
made
to
work
in
circuits
that
have
semiconductors. If the fuse needs replacement, it is
important that the same amperage rating and type is
used. A larger amperage rating or a fuse that does not
open
rapidly
will
not
prevent
damage
to
other
components.
F1 FUSE
Surge suppression diode (CR11) prevents too high
voltages that are abnormal (not normal) and transient
(temporary) from causing damage to controlled rectifier
(CR9) or field rectifier (CR10). Inside of rectifier module
(A2) there are resistance capacitance circuits connected
from anode to cathode of both controlled rectifier (CR9)
and field rectifier (CR10). These circuits give added
protection for abnormal transient peak voltages that can
cause damage at (CR9) or (CR10).
GENERATOR REGULATOR ASSEMBLY
A2. Rectifier module. CR9. Controlled rectifier.
CR10. Field rectifier. CR11. Surge suppression
diode.
Surge suppression diodes (CR7) and (CR8) are
connected in parallel, electrically. CR7 is installed on
the positive heat sink (E1) and CR8 is installed on the
negative heat sink (E2). These diodes are connected in
parallel to give the current capacity needed
for suppression of any abnormal transient peak voltages
that can cause damage to the rotating rectifiers (CR1
thru CR6).
ROTATING FIELD ASSEMBLY (RFA)
E1. Positive heat sink. E2. Negative heat sink. R6.
Suppression resistor.
E1 POSITIVE HEAT SINK
R6. Suppression resistor.
Suppression resistor (R6) gives a low resistance circuit
from the insulated windings to the shaft and cores of the
revolving field assembly (RFA). It this resistor was not
installed, air friction on the windings and heat sinks can
cause electrostatic charges. These charges can cause
voltages to become high enough to destroy the
insulation. Resistor (R6) is a 27,000 ohm resistor that
lets these electrostatic charges run off as they are
generated and prevents any voltage build-up. Because
of the Value and power rating of resistor (R6). a ground
failure at any point on the revolving field assembly (RFA)
will not prevent the generator from operating normally
and it will not cause damage to (R6).
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