GUARD AS 1746985 - Caterpillar

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 in the regulator circuit. As the current through exciter control field (L) decreases, the effective excitation in the exciter increases. This increases the generator output and the voltage will return to the desired value. As the load on the generator decreases, the voltage will increase. The saturable reactor will let more current flow in the regulator circuit. As the current flow through the exciter control field increases, the effective excitation in the exciter decreases. This decreases the generator output and the voltage will return to the desired value.Voltage level rheostat (H) is used to adjust the voltage output of the generator to the desired value.When the generator is to be operated in parallel with one or more other generators, it is necessary that an adjustment be made so the generator voltage will droop as load increases on the generator. The droop circuit is connected to the exciter armature. The exciter voltage causes DC current to flow in the circuit. The voltage droop adjustment is made with the voltage droop rheostat (D). When the setting of the voltage droop rheostat is moved from zero to a higher number, the resistance in the voltage droop circuit is decreased. When the voltage droop rheostat resistance is decreased, more current can flow in the droop circuit. This current flows through the center winding of DC controlled reactor (C) and changes its magnetic characteristics so there is less resistance to the flow of AC current through the outer coils. More AC current can then flow in the regulator circuit. As a result, more DC current will flow in exciter control field (L). The effective excitation in the exciter will decrease. This decreases the generator output voltage. A small load has little effect on the voltage droop circuit. Voltage droop increases as the exciter voltage increases with added load on the generator.Operation Of Generators With Compensating Current Transformer Type Regulators (Serial Numbers 600-Up)
WIRING DIAGRAM (TYPICAL EXAMPLE) A. Voltage droop transformer.B.