Kubota GL6000A-AU-B Workshop Manual page 128

GL6000A-AU-B, GL6000D-AU-B,GL9000A-AU-B, GL9000D-AU-B, WSM
The block diagram of GL Series A.V.R.'s is shown below. The A.V.R. consists basically of the components
detector (7) through transistor (4).
(1) Exciter Coil
(2) Rectifier
(3) Rotor Coil
(1) Detector
The detector (7) monitors the generator's output voltage. The generator's detection coil (9) is connected to this
component.
(2) Controller
The controller (6) is designed to compare the voltage picked up by the detector (7) with the preset reference
voltage and to give a transistor ON and OFF signal to the next circuit (GL6000A-AU-B, GL6000D-AU-B: drive circuit
(5), GL9000A-AU-B, GL9000D-AU-B: photocoupler). When the output voltage rises too high, it is made to drop; if it
drops too low, it is made to rise.
(3) Drive circuit
The drive circuit (5) is basically composed of multiple transistors. The drive signal from the previous circuit
controller (6) is weak. To intensify this signal, the final-stage transistor (4) that switches on and off the current to the
rotor coil (3) is activated. For comparison, let's imagine a gearbox that gives a large torque from a small force. While
the engine is stopped or in the low rpm range - that is, the generator voltage is not yet established, the drive circuit
(5) behaves to keep the transistor (4) fully on.
(4) Transistor
The transistor (4) is designed to switch on and off the rotor coil (3) current and to adjust the generator's output
voltage. On the GL Series A.V.R.s, the transistor is located projected from the mold with the heat sink.
(5) Rectifier
The rectifier (2) is intended to rectify the exciter output voltage and to feed power to the rotor coil (3). This
component consists of diode stack and electrolyte capacitor.
(4) Transistor
(5) Drive Circuit
(6) Controller
(7) Detector
2-M3
GENERATOR
(8) A.V.R.
(9) Detection Coil
9Y1211607GRM0003US0
9Y1211607GRM0004US0
KiSC issued 06, 2016 A