Electrical system — Engineering, Mashit 30

23 questions on electrical system, from the Engineering exam of Mashit 30. Battery, alternator, starter motor and fuses. Every question is shown with its correct answer, as in the official question pool.

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Questions on Electrical system

Which gearwheel does not turn while the engine is running normally? The starter-motor gear.
What liquid is added to a battery? Distilled water.
How does the electric starter motor turn the engine? Through gear wheels.
Do you need to run the engine to use the electric anchor windlass? It is advisable, to help supply the current.
What kind of electric current does a battery supply? Ordinary direct current.
How can you tell the positive terminal of a battery from the negative one? The positive terminal is thicker.
What does a hydrometer measure? The density of the electrolyte in the battery.
If it is not marked, how can you tell what voltage a battery can supply? By the number of cells.
What protects the electrical system against overload? The fuse.
What should you do when the alternator's output voltage is unsteady? Check the alternator drive belt.
In what units is battery capacity measured? Ampere-hours.
What is the function of the battery on board a vessel? To supply electrical energy to run the electrical systems.
In daytime, with the engine running and no electrical loads switched on, the ammeter shows 5 amperes for a long time. What does this mean? There may be a current leak or a short circuit in the electrical system.
When the VHF radio is switched on and transmitting, the voltmeter drops from 13.5 volts to 12.5 volts. What does this mean? The batteries are in good condition.
Where does the starter motor get its electrical power from? From the battery.
Why must you not smoke near a battery that is being charged? The hydrogen given off by the battery while charging may explode.
What must you check when charging a battery? That the vent holes in the caps are open.
What can a slack engine belt cause? Poor battery charging.
What protects electrical equipment from overcurrent or a short circuit? The fuse.
In what units is battery capacity measured? Ampere-hours.
With the navigation lights on, the voltage measured across the battery terminals is 10 volts. What does this mean? The battery is weak and probably faulty.
When you try to start, the starter motor clicks but the engine does not turn. What could be the cause? All of the above.
When you try to start, the engine turns over too slowly and does not "start". What is a possible cause? The battery terminals are not properly connected, or the battery is weak.

Electrical system — Engineering, Mashit 30

Questions on Electrical system

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