SHOE 4K7175 - Caterpillar

This manual covers the K65-12B voltage regulator which is used on SR4B 2600 Frame generators. The K65-12B regulator is typically located in the switchgear or the regulator is typically located in a remote generator set control panel.The K65-12B voltage regulator (3) keeps the generator output voltage constant with changing loads. The voltage regulator controls the DC voltage and current that is supplied to the exciter stator (8). The regulator senses the generator voltage through the generator sensing leads (2). The sensing leads are connected to the following terminals: 20, 22 and 24. The sensed voltage is then compared to a reference voltage. The value of the reference voltage is set by the voltage adjust rheostat on the regulator. The value of the reference voltage may also be set by an external voltage adjust rheostat. When the regulator senses a decrease in output voltage due to an increase in load, the regulator will increase the DC voltage on wires F1 and F2 (12). This increases the magnetic field in the exciter stator (8). The increased magnetic field in the exciter stator increases the AC voltage and current, which is induced in the exciter rotor (7). This increased three-phase AC voltage from the exciter rotor causes more AC current to flow. The three-phase AC voltage is then rectified to DCV by the three-phase full wave rectifier (9). The increased DC output from the bridge rectifier is carried to the main rotor (6) by conductors, which are routed through a passage in the generator shaft. Increased current through the main rotor increases the magnetic field of the generator. The increased magnetic field induces a larger AC voltage into the main stator (5). Therefore, the three-phase AC voltage (1) increases until the voltage regulator no longer senses a decreased output voltage.When the voltage regulator senses an increase in output voltage due to a decrease in load, the regulator will decrease the DC voltage to the exciter. A decrease in generator voltage will occur due to similar responses, as described above.
Illustration 2 g00779058
The K65-12B Voltage Regulator (13) Terminal strip for attachments (14) Droop adjustment (15) Factory calibration of the voltage adjustment range (16) Voltage adjustment (17) Knee frequency adjustment (18) Stability adjustment (19) Terminal strip for sensing and power
Illustration 3 g01021519
The Cat K65-12B Voltage Regulator presents an electrical shock/electrocution hazard. This hazard will cause serious injury or death. Service by trained personnel only.The terminals and heat sinks