VIDEO
HIGHLIGHT
Log InSign up
Practical Marine Electrical Knowledge: Program 3. Generators and Main Circuit Breakers
SummaryTranscriptChat

Practical Marine Electrical Knowledge: Program 3. Generators and Main Circuit Breakers

Overview of Marine Electrical Knowledge Program 3

Main Power Sources and Circuit Breakers

  • This program focuses on main power sources, circuit breakers, synchronizing, load sharing, fault-finding techniques, and testing procedures for circuit breakers.
  • Emphasizes the importance of understanding the electrical system layout and components upon joining a ship, particularly the emergency switchboard and generator startup systems.

Electrical Safety Protocols

  • The golden rule for electrical safety: isolate circuits before work by removing fuses or locking circuit breakers in the open position.
  • A switchboard is only considered dead when all AC generators are stopped and disconnected; this must be clearly understood to ensure safety during maintenance.

Typical Power Generation Schemes

  • Most ships have two main AC generators and one emergency generator; typical output is 440 volts at 60 Hz or 380 volts at 50 Hz.
  • Emergency generators start automatically upon sensing failure in main power due to loss of steam pressure, voltage, or frequency.

Synchronization of AC Generators

  • Synchronizing involves matching an incoming generator's voltage with that on bus bars before closing its circuit breaker.
  • Load sharing between synchronized generators is crucial during varying power demands; adjustments are made to ensure equal distribution.

Automatic Voltage Regulators (AVRs)

  • AVRs maintain supply voltage by adjusting exciter current based on changing loads; faults can cause unexpected voltage fluctuations.
  • Reverse power relays protect alternators from backflow into bus bars; periodic checks are necessary to ensure proper function.

Testing Procedures for Generators

  • Insulation resistance tests should be conducted safely from the incoming side of the generator breaker while ensuring all safety protocols are followed.
  • If an AC generator fails to generate output, potential causes include loss of residual magnetism which can be restored using DC current from batteries.

Troubleshooting Circuit Breakers

  • Circuit breakers connect AC generators to bus bars safely but may fail to close normally due to various faults such as loose connections or malfunctioning coils.
  • Manual closure attempts can help diagnose issues; if problems persist after checking connections and circuitry, further investigation is required.

This concludes Program 3's insights into marine electrical knowledge regarding power generation systems and troubleshooting techniques.

Playlists: Practical Marine Electrical Knowledge
Video description

This is Program 3 of VIDEOTEL series on Practical Marine Electrical Knowledge. Designed to assist sea-going personnel in their understanding of the safe operation, testing and maintenance of ship's electrical equipment and services. Examines practical electrical maintenance and fault-finding procedures on board various ship types. The series is made up of 8 programs. Program 3 deals with main power sources and their circuit breakers, including synchronizing, load sharing, fault-finding techniques and remedies. Also, test procedure on circuit-breaker if it fails to close normally. There are many system variations around. So, it's most important that you become familiar with components of the main switchboard immediately you join a ship. Pay particular attention to the layout of emergency switchboard and automatic start system of emergence generator. This study will pay dividends during a blackout or when troubleshooting caused of major breakdown. Generators and Main Circuit Breakers Electrical Safety Golden Rule is: Before any work is done on the electrical installation, first, isolate the circuit by removing the supply fuses or locking the circuit-breaker in the open position. So, the circuit cannot be energized accidentally. Then, post a warning sign to alert others that the circuit is being worked down. Then prove the circuit dead with voltmeter or approved line tester. ______________________________ This video series explains a ship's electrical system, including its generation plant, switchboards and distribution network. Electrical safety and safe working practice are stressed throughout with the significance of circuit faults and the various forms of protective switchgear. Based on book "Practical Marine Electrical Knowledge" which covers every aspect of a ships electrical system and includes correct operation, safety, testing, UMS requirements and standards for Classification Society Surveys. ______________________________ Timeline of Program 3. Generators and Main Circuit Breakers: 0:45 Content 1:03 When you joined a ship 1:30 Electrical Safety Golden Rule 2:16 Electrical Rescue Procedure 2:21 Types of generators on board 3:01 Shaft generators 3:22 Automatic start of emergency diesel-generator 3:35 Emergency Diesel Auto-Start Scheme Explanation 4:51 Advise 4:57 Synchronizing of AC generators 7:50 Automatic voltage regulator 9:02 Reverse power 10:03 Trip relay 10:15 Undervoltage and overcurrent relays, short-circuit trip 10:39 Typical tests 10:57 Insulation resistance and continuity test 11:09 Safety precaution 12:24 Exciter failure 12:42 Residual magnetism 12:52 Reestablishing residual magnetism 13:23 Keep in mind 13:57 Field coil 14:40 Testing to earth 15:07 Testing to open circuit 16:00 What if excitation working well 18:30 Testing diodes 18:40 Check capacitor 19:20 AC generator circuit-breaker 22:23 Conclusion ______________________________________ Made by VIDEOTEL 1992 archive #marine #electrical knowledge