Electrical Flashcards
How would you describe an ampere ?
A. The measure of power generated
B. Measure of the electrical current flow
C. Measure of the potential difference between the 2 points.
D. Measure of the opposition on material offers.
B. Measure of the electrical current flow
The deck lights of vessel connect to a 12 volt electrical system by means of wiring with a maximum current rating of 10 amps. Select the total maximum wattage of deck lights which can be used.
A. 120 watts
B. 12 watts
C. 60 watts
D. 24 watts
A. 120 watts
MED3 is qualified to carryout basic maintenance. What is the maximum AC voltage ?
A. Less than 240 v
B. Less than 32 v
C. Less than 50 v
D. Less than 115 v
B. Less than 32 v WHS
C. Less than 50 v AMSA
Prior to repairing a damaged low voltage cable you must first …
A. Make sure the area is free from hazards
B. Ensure the circuit breaker is in good condition
C. Determine what the cable is connected to
D. Isolate the circuit or shut down the power supply
D. Isolate the circuit or shut down the power supply
Dangers to be aware of when charging a battery will include …
A. Inadequate ventilation
B. Damaging equipment from incorrect installation
C. Sparks acid splashes fire explosion
D. All of the above
D. All of the above
What does a hydro meter measure
A. Acid content
B. Specific gravity
C. Amps
D. Water flow
B. Specific gravity
Who should repair 240 v AC faults aboard the vessel ?
A. Marine electrician
B. A licensed electrician
C. The engineer
D. The vessel master
B. A licensed electrician
An RCD is a residual current device and does not ..
A. Sense any current in balance between the hot and neutral wires
B. Sense an in balance if there is a leak from hot or neutral to the ground
C. Shut down the circuit and cut off any potential hazardous currents that would otherwise end up on the grounding circuit
D. Require a break in the AC to DC ground connection
D. Require a break in the AC to DC ground connection
What is a double pole circuit breaker ?
A. A circuit breaker with twice the insulation of a normal single pole unit.
B. A circuit breaker that opens two negative circuits at once
C. A circuit breaker that opens 2 positive circuits at once.
D. A circuit breaker that opens both positive and negative circuits.
D. A circuit breaker that opens both positive and negative circuits.
How would you describe reverse polarity ?
A. Electrons flowing in the positive and negative
B. A system wrongly wired so that the neutral negative wire is positive / active.
C. Different wiring plans in the northern hemisphere.
D. Confusion if a switch is not turned off properly.
B. A system wrongly wired so that the neutral negative wire is positive / active.
What is the specific gravity reading of a flat battery ?
A. 1.18
B. 1.15
C. 1.1
D. 1.3
C. 1.1
What is the practical difference between a fuse and a circuit breaker ?
A. Fuse can be reset
B. Circuit breaker needs to be replaced
C. Circuit breaker is able to reset
D. Fuse can be regenerated
C. Circuit breaker is able to reset
A battery gives off hydrogen gas when being charged or under load Why ?
A. The battery contains hydrochloric acid and water.
B. The battery contain sulphuric acid and water
C. The battery contains lead acid and water
D. The battery contain pole and water
B. The battery contain sulphuric acid and water
When testing a battery other than a hydrometer what equipment is best used to determine the condition of a battery ?
A. Screw driver
B. Multimeter
C. Mega tester
D. Load tester
D. Load tester
No your switch board what gauge shows the current flow in use ?
A. Synchroscope
B. Volt meter
C. Watt meter
D. Ammeter
D. Ammeter
What would you locate prior to starting a vessels electrical system ?
A. Switch board
B. Battery banks
C. Shore power procedures
D. Startup electrical procedures
D. Startup electrical procedures
If it is discovered that the prop is corroding this could be
A. Electrolysis
B. Polluted water
C. Wrong prop
D. Marine growth
A. Electrolysis
What is achieved by wiring a battery in parallel ?
A. Lowering the total cell capacity
B. Lowering the amp hour capacity
C. Increasing the amp hour capacity
D. Increasing the voltage
C. Increasing the amp hour capacity
When connecting to shore power you notice the polarity light shows a warning you would immediately ?
A. Check the switch on the dock
B. Call a marine electrician
C. Remove the power cable between the shore and the vessel
D. Turn you generator on
C. Remove the power cable between the shore and the vessel
When you disconnect your shore power what is the primary requirement before operating the vessels power
A. Turn the switchboard from shore to ship
B. Disconnect the power cable from ship and shore
C. Turn on your onboard genset
D. Switch off shore power at the shore switch
B. Disconnect the power cable from ship and shore
When overloaded an electrical fuse
A. Melts
B. Trips off
C. Prevents rise in voltage
D. Prevents rise in current
A. Melts
A vessel has a 12 volt electrical system on its nav light circuit it has 4 x 40 watt lamps. Select the suitable fuse
A. 12 amps
B. 15 amps
C. 20 amps
D. 30 amps
B. 15 amps
What hazard exists when charging a battery ?
A. Acid splashes flammable and toxic gases
B. Sparks and shorts
C. Over charging causing equipment failure
D. All of the above
D. All of the above
2 x 12 volt batteries connected in parallel would produce how many volts
A. 240
B. 24
C. 12
D. 6
C. 12
Batteries connected positive to negative would be
A. In series
B. Shorted
C. In Parallel
D. Discharging
A. In series
If the voltage is higher than normal when the alternator is charging what could this be indicating ?
A. Batteries are flat
B. Fan belt is loose
C. The voltage regulator has failed
D. The rectifier has failed
C. The voltage regulator has failed
When must a qualified electrical contractor carry out electrical work as the requirements of state / territory licensing ?
A. When the batteries are too heavy
B. When the voltage is above 50 VAC or 120 VDC
C. When the voltage is above 120 VAC or 50 VDC
D. When the batteries need topping up
B. When the voltage is above 50 VAC or 120 VDC
A starter motor not cranking properly may indicate
A. Loose battery connections
B. Corroded Connections
C. Battery flat
D. All of the above
D. All of the above
What is the purpose of connecting batteries in series ?
To increase the voltage
What is purpose for a parallel connection ?
To increase the amperes
When is it dangerous to disconnect a battery ?
When it is charging
What fluid is used to top up battery electrolytes ?
Distilled or de mineralised water
List checks for the electrical system
Terminals
Insulation
Fuses
Circuit breakers
Battery levels
The starter motor makes a rapid clicking noise when trying to start what could be the causes ?
Solenoid stuck
Flat battery
