840534 Volvo.Penta Delivery valve

Illustration 1 g00627416
Allowable Combinations of Unbalanced Loads
Block Loading
Block loading is the instantaneous application of an electrical load to a generator set. This load may be anywhere from a moderate percentage of the rated load up to the rated load.The block loading capability of a generator set depends on the following factors.
Engine transient response
Voltage regulator response
Type of the voltage regulator
Altitude of operation of the generator set
Type of load (power factor for the load)
The percentage of load before the application of the block loadIf derating for the block load is required, refer to ISO 3046 Standards or SAE J1349 Standards. Also, reference Engine Data Sheet, LEKX4066, "Loading Transient Response" and Engine Data Sheet, LEKX4067, "Block and Transient Response". Note: ISO stands for International Standards Organization.Power Factor
The power factor represents the efficiency of the load. Power factor is the ratio of apparent power to total power. The power factor is expressed as a decimal. The power factor represents that portion of the current which is doing useful work. The portion of current which is not doing useful work is absorbed in maintaining the magnetic field in motors or other devices.In most applications, electric motors and transformers determine the power factor of the system. Induction motors usually have a 0.8 or smaller power factor. Incandescent lighting is a resistive load of about 1.0 power factor, or unity.The power factor of a system may be determined by a power factor meter or by calculations. Determine the power requirement in kW by multiplying the power factor by the kVA that is supplied to the system. As the power factor increases, the total current that is supplied to a constant power demand will decrease. For example, a 100 kW load at a 0.8 power factor will draw more current than a 100 kW load at 0.9 power factor. A higher power factor will result in full engine load at less than the rated amperage of the generator. A lower power factor increases the possibility of overloading the generator.Note: If no other power factor is specified, Caterpillar generators are designed for a 0.8 lagging power factor. Excitation Systems
Permanent Magnet Pilot Excited Generators
Permanent Magnet Pilot Excited (PMPE) generators receive power for the voltage regulator from a pilot exciter, rather than the main armature. The pilot exciter consists of a permanent magnet rotor and a permanent magnet stator. The pilot exciter operates independently from the generator output voltage. Constant excitation during a large load application is possible because the irregularities that occur in generator output voltage are not fed back into the exciter. Such irregularities can be caused by load conditions. The independent operation also allows the generator to better sustain an overload for a short duration. The pilot exciter also ensures that the generator will start properly even if the rotating field becomes completely demagnetized.Low Idle Adjustment
Generator sets normally have a higher low idle setting than industrial engines. Low idle will be approximately 66% of the full load speed of 60 Hz units.There is no low idle stop on generator sets with electronic governors. On generator sets with mechanical governors, the low idle is set at the factory. The low idle should only be adjusted by your Caterpillar dealer if adjustment is required.Note: Operating the generator set at low idle speed for an extended time will cause some voltage regulators to shut off. The generator set must be completely shut down. Then, the generator set must be restarted in order to allow the voltage regulator to produce an output again.Standby Generator Sets
Most standby units are installed with controls that will start the unit automatically. Standby units perform the following tasks without an operator in attendance: start, pick up the load, run and stop.Standby units cannot change the governor control automatically. Standby units cannot change the voltage settings automatically. The governor speed and voltage level must be preset for the proper operation of the standby unit. Whenever the set is operated manually, be sure that the governor speed and voltage levels are correct for automatic operation. Check all switches for the proper setting. The start select switch should be in the AUTOMATIC position. Emergency Stop Switches should be in RUN position.Generator Options
Space Heaters
Space heaters are installed for operation in high humidity conditions. For more information on space heaters, refer to Maintenance Section, "Space Heater - Test".Embedded Temperature Detectors
The generators are equipped with embedded temperature detectors. The detectors are installed in the slots of the main armature. The main armature is also called a stator. The detectors are used with the equipment that is provided by the customer. Thus, the temperature of the main armature winding can be measured or monitored.Bearing Temperature Detectors
The generator is equipped with Bearing temperature detectors. Bearing temperature detectors measure main bearing temperature. Bearing temperature detectors are used with the equipment that is provided by the customer. Thus, the temperature of the bearing can be measured or monitored. Bearing temperature measurements may help to prevent premature bearing failure.