Main Switch Board (MSB) is an essential component in electrical power distribution systems. Here are some key points about MSB:
1. Cabinet and Compartments: MSB cabinet is typically made of steel sheet and divided into multiple sections or compartments to house various components and devices.
2. Power Collection: Electrical power from the generators is collected in the MSB through the Generator Switch Board/Panel.
3. Power Distribution: The MSB distributes electrical power to various utilization devices through Group Feeder Panels or Group Starter Panels. Devices operating at 440 V are supplied from 440 V bus bars, while those requiring 220 V are supplied from 220 V bus bars. Step-down transformers are used to step down the voltage from 440 V to 220 V.
4. Shore Supply Connection: During dry dock or when the ship is connected to shore power, the shore supply is connected to the MSB for power distribution.
5. Symmetrical Arrangement: The MSB is arranged symmetrically, with the Generator Switch Board/Panel positioned in the middle, and the Feeder Panels/Group Starter Panels distributed equally on either side.
6. Devices and Instruments: MSB houses various devices, instruments, and components such as switch gears/circuit breakers, main bus bars for 440 V and 220 V, bus-tie connections, monitoring and controlling systems, measuring and indicating instruments (e.g., ammeters, voltmeters, frequency meters, watt meters, synchronizing unit, power factor meter, insulation resistance meter), and step-down transformers.
7. Safety Features: MSB is equipped with various safety features to protect the system and personnel. These include circuit breakers with arc chutes, short circuit trip, overload trip, low frequency trip, under voltage trip, phase imbalance trip, reverse power trip, preferential trip, over-speed trip, fuses, earth fault indicators, earthing of panel doors, ebonite rod, rubber matting in front and back of the MSB, dead-front type construction, and maintaining a distance of 0.6 meters between the MSB and bulkhead.
8. Pipeline Restrictions: There should be no water, steam, or oil pipelines passing in the vicinity of the MSB to prevent any potential hazards.
Regular maintenance, inspections, and adherence to safety procedures are crucial for the proper functioning and reliability of the MSB. Compliance with relevant regulations and manufacturer guidelines is essential for the safe operation of the electrical distribution system on board a ship.