Emergency Shutdown

In the event of engine overspeed, high jacket water temperature, or low lubricating oil pressure, the engine may be shut down automatically and disconnected from the main load by tripping the main circuit breaker. In addition, an indicator may light or an alarm may sound to indicate the cause of shutdown. After an emergency shutdown and before the engine is returned to operation, the cause of shutdown should be investigated and corrected.

NOTE: It is important to check the safety controls at regular intervals to determine that they are in good working order.

Basic Operating Precautions

The order that you post in the station for the guidance of the watch standers should include a general list of operating rules and electrical safety precautions. BE SURE YOU ENFORCE THEM!

The important operating rules are relatively few and simple. They are as follows:

1. Watch the switchboard instruments. They show how the system is operating and reveal overloads, improper division of kilowatt load or of reactive current between generators operating in parallel, and other abnormal operating conditions.

2. Keep the frequency and voltage at their correct values. A variation from either will affect, to some extent at least, the operation of the electrical equipment of the base. This is' especially true of such equipment as teletypewriters or electrical clocks. An electrical clock and an accurate mechanical clock should be installed together at the generating station so that the operators can keep the generators on frequency.

3. USE GOOD JUDGMENT WHEN RE-CLOSING CIRCUIT BREAKERS AFTER THEY HAVE TRIPPED AUTOMATICALLY. For example, generally the cause should be investigated if the circuit breaker trips immediately after the first reclosure. However, reclosing of the breaker the second time may be warranted if immediate restoration of power is necessary and there was no excessive interrupting disturbance when the breaker tripped. It should be kept in mind, however, that repeated closing and tripping may damage the circuit breaker and thus increase the repair or replacement work.

4. Don't start a plant unless all its switches and breakers are open and all external resistance is in the exciter field circuit.

5. Don't operate generators at continuous overload. Record the magnitude and duration of the overload in the log; record any unusual conditions or temperatures observed.

6. Don't continue to operate a machine in which there is vibration until the cause is found and corrected. Record the cause in the log.

The electrical safety precautions that should be observed by the station personnel are as follows:

1. Treat every circuit, including those as low as 24 volts, as a potential source of danger.

2. Except in cases of emergency, never allow work on an energized circuit. Take every care to insulate the person performing the work from ground. This may be done by covering any adjacent grounded metal with insulating rubber blankets. In addition, provide ample illumination; cover working metal tools with insulating rubber; station men at appropriate circuit breakers or switches so that the switchboard can be de-energized immediately in case of emergency; and make available a person qualified to render first aid for electric shock.