RETAINER-SEAL 1259710 - Caterpillar

Sensing Voltage
The sensing voltage is the three-phase AC voltage at terminals 20, 22 and 24. The ratio of the sensing voltage to the generator voltage depends on the ratio of the windings of the potential transformers (PT).Reference Voltage
The reference voltage is set by the voltage adjust rheostat or by an external voltage adjust rheostat. The reference voltage is the desired voltage on the output of the generator at rated frequency.Knee Frequency
The knee frequency is adjusted by turning the knee frequency adjustment. Without setting the knee frequency, generator voltage would follow generator frequency proportionally. If the generator frequency is above the adjusted knee frequency, the regulator maintains the generator voltage at the reference voltage.V/Hz Slope
If the generator frequency drops below rated frequency, the regulator will regulate the voltage to a lower reference voltage. This helps the engine to recover quickly during block loading. The reference voltage is proportional to the generator frequency. There are two slopes that can be selected: 1 V/Hz and 2 V/Hz. The jumper between terminals 6a and 8 creates a 1 V/Hz slope. In this case, a 1 percent change in frequency below the knee frequency will produce a 1 percent lower reference voltage. In order to select a 2 V/Hz slope, remove the jumper between terminals 6a and 8. In this case, a 1 percent change in frequency below the knee frequency will produce a 2 percent lower reference voltage. Droop
When a generator set operates in parallel with another generator set, it is necessary for the output voltages to match in order to prevent circulating currents. The droop will raise the reference voltage or the droop will lower the reference voltage in response to the power factor. This slight raising of the output voltage or lowering of the output voltage results in the reactive load sharing between gensets that are operating in parallel.Stability
Because of a time delay between the voltage sensing and the output of the regulator, the generator voltage can become unstable. The time delay varies. This delay depends on time constants for the exciter and the generator. The stability circuit slows the response of the regulator in order to stabilize the voltage. The stability adjustment is used in order to ensure that the regulator responds as quick as possible, and the regulator keeps the voltage stable.Overexcitation Protection
The overexcitation protection will shut off the regulator at 90 5% DCV. The overexcitation protection will take the output to zero in more than 30 seconds. The output can be 125 DCV for more than 10 seconds.The generator set must be shut down in order for the regulator to reset.