SPRING-VALVE 7S7144 - Caterpillar

Personal injury or death can result from high voltage.When power generation equipment must be in operation to make tests and/or adjustments, high voltage and current are present.Improper test equipment can fail and present a high voltage shock hazard to its user.Make sure the testing equipment is designed for and correctly operated for high voltage and current tests being made.When servicing or repairing electric power generation equipment:
Make sure the unit is off-line (disconnected from utility and/or other generators power service) , and either locked out or tagged DO NOT OPERATE.
Remove all fuses.
Make sure the generator engine is stopped.
Make sure all batteries are disconnected.
Make sure all capacitors are discharged.Failure to do so could result in personal injury or death. Make sure residual voltage in the rotor, stator and the generator is discharged.
Accidental engine starting can cause injury or death to personnel working on the equipment.To avoid accidental engine starting, disconnect the battery cable from the negative (−) battery terminal. Completely tape all metal surfaces of the disconnected battery cable end in order to prevent contact with other metal surfaces which could activate the engine electrical system.Place a Do Not Operate tag at the Start/Stop switch location to inform personnel that the equipment is being worked on.
For generators with Auxiliary Winding Regulation Excitation Principle (AREP), the voltage regulator is powered by two auxiliary windings. These windings are independent from the voltage sensing circuit. The first winding is labelled as "X1" and "X2". This winding has a voltage that is proportional with the output voltage of the generator. The second winding is labelled as "Z1" and "Z2". This winding has a voltage that is proportional to the current of the stator. The voltage from the power supply is rectified and filtered before being used by the AVR monitoring transistor. The generator has a capacity of 3 IN for 10 seconds for a short circuit current. The generator also has good immunity to distortion from the generator load.For generators with PMG excitation, a permanent magnet generator is added to the generator at the rear of the generator. The PMG supplies the voltage regulator with a voltage that is independent of the main generator winding. The generator has a capacity of 3 IN for 10 seconds for a short circuit current. The generator also has good immunity to distortion from the generator load.The voltage regulator monitors the output voltage of the generator. The voltage regulator corrects the output voltage by adjusting the excitation current.
Table 1
Sustained short circuit capacity (AREP and PMG) 3 IN for 10 seconds
Standard power supply (AREP) Two auxiliary windings
Supply for shunt max 140 VAC at 50/60 Hz
Rated overload current 10 amperes for 10 seconds
Electronic protection for overload and loss of voltage sensing Excitation ceiling current for 10 seconds and return to approximately 1 ampere
THE GENERATOR MUST BE STOPPED IN ORDER TO RESET THE PROTECTION.
Fuse "F1" on input side "X1" and "X2"
Voltage sensing 5 VA that is isolated by the transformer
0-110V terminals 95 to 140 V
0-220V terminals 170 to 260 V
0-380V terminals