Types of fuses
- High reputuring capacity fuses.
- Cartridge fuse
- Semi enclosed fuse.
SURVIVER MAY ASK HOW WILL YOU ORDER FUSES?
- CURRENT RATING
- VOLTAGE
- BREAKING CAPACITY
- FUSE TYPE
- FREQUENCY
- PRODUCT TYPE.
FUSES meo class4
CIRCUIT BREAKER ACB meo class4
MCB - Miniature circuit breaker- 5- 50 amp
MCCB - moduled case circuit breaker 50-1500amp
ACB- Air Circuit breaker- 400-2000amps
Acb safeties
- Arc runner arc chutes
- Breaker open fast before taking out acb
- Simultaneous closing of all 3 units of each phase.
- Breaking speed as High as possible.
TYPES OF STARTERS AND WHERE IT IS USED IN SHIP? MEOCLASS4
Types of starters?
- Dol (direct online starter)- (5hp)
- Star delta starter- (5 hp to 20 hp)
- Auto Transformer - (20 hp to 50hp)
- Soft starter - (above 50hp)
Where its used onboard?
Dol starter
- Boiler feed pump
- Circulating pump
- Gear pump
- Bilge pump
- Fwg distilled pump
- Stern lub oil pump.
Star delta starter
- Jcw pump (HT and LT)
- Ballast pump
- Sea water pump.
Auto Transformer
- Bow thruster
- M/e lo pump
Soft starter
- Washing machine
- Spring drier
- Grinder.
WELDING TRANSFORMER MEO CLASS4
WHAT IS WELDING TRANSFORMER?
- IT IS A STEP DOWN TRANSFORMER USED TO REDUCE THE VOLTAGE APPROXIMATELY 15V - 45V TO PRODUCE THE CURRENT OF 200- 600AMPS IN SECONDARY WINDING,
- PRIMARILY WINDING->THIN WIRE AND MORE TURN(BECAUSE LOW CURRENT THIN WIRE CAN CARRY)
- SECONDARY WINDING ->THICK WIRE LESS TURN(HIGH CURRENT IS PROVIDED)
CONSTRUCTION OF WELDING TRANSFORMER?
- It is a auto Transformer
- It has a magnetic field core with primary winding which is thin wire and large number if turn.
- A secondary winding with less turn thick wire.
- Due to this arrangement its a step down Transformer.
- So we get less voltage and high current output.
- DC WELDING TRANSFORMER is also same working like ac welding Transformer. But in dc welding Transformer rectifier is provided to convert ac, in out put of secondary winding.
- Also connect a indictor or filter to get the smooth dc current,
- This is the construction of welding Transformer.
(Please check the image)
Working of welding Transformer?
- Its is the step down Transformer so we get les Voltage and high current.
- Which is near 15 to 45v and 200amp to 600amp
- For adjusting the voltage on secondary side there are topping on secondary winding by this we can get required amount nog secondary current for welding.
- Topping are connected to several High current switches,
- welding electrodes and the other end is connected to welding piece.
- When a high current flow in a large amount of I2.R, heat is produced due to contact resistance between welding piece and electrode.
- Because of this High heat tip of the electrode melted and fill the gaps between welding piece.
Why we can't synchronous ship's generator and shore supply?
Reason is simple,
SURVIVER MAY ASK WHY WE CAN'T SYNCHRONISE SHORE SUPPLY AND GENERATOR?
- Both have different frequencies or voltage,
- While ship's GENERATOR is running we can't close the shore supply circuit breaker, is because interlocking is provided.
Why A/E crank shaft is drilled for lubrication but not in M/E ?
- It will reduce the strength of the crankshaft.
- May possible to occur crack or failure
- So we drill the hole in a/e Engines.
- For main engine we use semi build crank shaft .- web and crank pin both are single oice
- For a/e engine we use forged crank shaft- its fully moulded type.good fatigue strength.
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