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DANGER: Shock/Electrocution Hazard-Do not operate this equipment or work on this equipment unless you have read and understand the instructions and warnings in the Operation and Maintenance Manual. Failure to follow the instructions or heed the warnings will result in serious injury or death. |
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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:
Failure to do so could result in personal injury or death. Make sure residual voltage in the rotor, stator and the generator is discharged. |
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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. |
The voltage regulator is located in the enclosure for the control panel or in the terminal box on the generator.
The Automatic Voltage Regulator (AVR) may control any of the following excitation systems: AREP, PMG and SHUNT. The AVR monitors and corrects the alternator output voltage by adjusting the excitation current.
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| Illustration 1 | g03368326 |
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The voltage regulator is located in the terminal box on the generator or in the enclosure for the control panel. (1) Terminal Box on the Generator (2) Enclosure for the Control Panel | |
The generator set may include one of the following voltage regulators.
Permanent Magnet Generator (PMG) excitation system
This is fitted at the rear of the machine and connected to the R438 IVR. The PMG supplies the IVR with constant voltage which is independent of the main generator winding. As a result the machine has a short-circuit current capacity and good immunity to distortions generated by the load.
These voltage regulators may have an optional remote potentiometer for voltage adjustment. This potentiometer is 1000 ohms 0.5 W minimum. The adjustment range is 5%. The voltage range is limited by the internal potentiometer "P2". Remove "ST4" in order to connect the potentiometer. A 1000 ohm potentiometer, or 470 ohm potentiometer may also be used on the IVR.
Integrated Voltage Regulator (IVR)
The IVR is a function in the EMCP 4 that controls the generator voltage, optimizes transient performance, and provides feature specification.
IVR may control any of the following excitation systems: Self Excitation (SE), Internal Excitation (IE) and Permanent Magnet (PMG) excitation systems.
For more information about IVR, see Application and Installation, LEBE0006, Application and Installation, LEBE0007, and Special Instruction, REHS9106.
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| Illustration 2 | g03457036 |
The EM 10 excitation module provides excitation current to the generator, and is controlled by the IVR function in the EMCP 4 controls.
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| Illustration 3 | g03457278 |
- If a short-circuit fault occurs at the generator terminals, the EM 10 will allow the excitation current to rise to the upper limit value set by the adjustment potentiometer (maximum 10 Amps).
- The excitation current will be clamped at the upper limit value for 10 seconds (fixed internally).
- After 10 seconds, the excitation current is reduced to a value of 10% of the potentiometer setting.
For more information about EM 10, contact your Cat dealer.