COVER GP-OIL PAN 6N5922 - Caterpillar

Voltage level resistor (if so equipped).G. Blocking rectifier.H. Voltage level rheostat.I. Generator field.J. Exciter armature.K. Exciter field.L. Exciter control field.M. Generator armature.Generator field (I) is connected to the engine flywheel through the generator shaft and coupling. Exciter armature (J) is belt driven from the generator shaft. Exciter field (K) is stationary and has residual magnetism. As the exciter armature turns, the coils move through the magnetic lines of flux around the exciter field. This generates an AC voltage in the exciter armature. The AC voltage is changed to DC by a commutator and brushes. The DC current flows from the brushes to generator field (I) and exciter field (K).The current that flows to the exciter field will cause the magnetic lines of flux around exciter field (K) to get stronger. The voltage induced in the exciter armature will increase. Current flow in the exciter circuit is limited by voltage level resistor (F) and voltage level rheostat (H). The voltage level rheostat can be adjusted to control the amount of current flow in the exciter circuit. Blocking rectifier (G) prevents reverse polarity operation of the exciter.Current flow through generator field (I) will cause magnetic lines of flux. As the generator field turns, the magnetic lines of flux move through the stationary windings of generator armature (M). This generates an AC voltage in the generator armature. Most of the AC voltage goes directly to the load. A small amount is used by the regulator circuit to control the output of the generator.As the engine speed increases to the desired rpm, the exciter voltage increases also. This voltage is limited by the amount of field current that can flow through the resistance of voltage level resistor (F), voltage level rheostat (H), and exciter field (K). The maximum value of exciter voltage would cause so much current to flow in generator field (I) that the AC voltage induced in generator armature (M) would be more than the rated voltage.
DC CONTROLLED REACTOR TYPE REGULATORThe regulator is used to control the exciter voltage. AC voltage from the generator armature is given to the regulator circuit at terminals 10 and 2. Full wave rectifier (E) changes the AC current to pulsating DC. This DC current then flows through exciter control field (L). The exciter field coils and the exciter control field coils are both wound on the exciter field poles. The coils are wound so that the magnetic lines of flux around one are opposite the magnetic lines of flux around the other. This is illustrated by the arrows near each coil. Because of the opposite magnetic polarities of these two fields, the effective excitation in the exciter is the difference between the magnetic fields of the two coils. A change in the amount of current flow through exciter control field (L) will cause a change in generator output voltage.Saturable reactor (A) acts as a valve. As the load on the generator increases the voltage will decrease. The saturable reactor will let less current flow