a) State the reason for turning the engine with the turning gear prior to starting (5) b) State the reason for leaving the indicator cocks on main engine cylinder open when the engine is turned initially with the turning gear. (5)

  MOTOR ENGINEERING KNOWLEDGE

MEO CLASS 4 & 5 COMBINED

Question Bank by DoS Bangladesh

       IMPORTANT QUESTION FOR WRITTEN EXAM

a) State the reason for turning the engine with the turning gear prior to starting (5)

    b) State the reason for leaving the indicator cocks on main engine cylinder open when the engine is turned initially with the turning gear. (5)

 

Ans (a): reason for turning the engine with the turning gear prior to starting:

The turning gear or turning engine is a reversible electric motor which drives a worm gear which can be connected with the toothed flywheel to turn a large diesel. A slow-speed drive is thus provided to enable positioning of the engine parts for overhaul or examine purposes. The turning gear is also used to turn the engine one or two revolutions prior to starting. This is a safety check to ensure that the engine is free to turn and to prevent damage caused by fluid leaking into any of the cylinders. Permission from the bridge must be sought before turning the engine. Pre-lubrication should be carried out.

 

Ans (b): reason for leaving the indicator cocks open:

Slow turning operation must be carried out at the latest possible moment before starting. The indicator cocks must always be open when the turning gear is operated. Because,

1.      The indicator cocks are kept open while slow turning the engine by turning gear otherwise the turning gear will not be able to turn the engine against compression pressure if the cylinder is air lock & the mechanism may damage.

2.      Ensure chamber is not air lock.

3.      Ensure no water or carbon particle has collected in the cylinder.

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