Electricidad 3

Local action in a nickel-cadmium battery is offset by __________.

• separating the positive and negative plates with plastic spacers

• separating the positive and negative plates with resin impregnated spacers

• adding a small amount of lithium hydroxide to the electrolyte

• trickle charging

An insulation resistance test is performed on a particular  piece of electric equipment.  In addition to the resistance reading, what information listed below should be entered in the electrical log?

• The maximum allowable operating temperature of the machine.

• The temperature of the machine at the time the resistance reading was taken.

• The normal temperature rise of the machine.

• The complete nameplate data from the resistance test instrument used to obtain the reading.

The reason some electric cables are formed of stranded wire is to __________.

• increase the current carrying capability for a given size wire

• increase their flexibility

• decrease the weight for a given size wire

• assure good conductivity at junction points

A lead-acid battery is considered fully charged when the __________.

• electrolyte gasses freely

• battery charger ammeter indicates a positive reading

• terminal voltage reaches a constant value at a given temperature

• specific gravity of all cells reaches the correct value and no longer increases over a period of 1 to 4 hours

Local action in a dry-cell, or lead-acid storage battery is the process whereby __________.

• hydrogen gas is liberated

• the electrolyte compensates for overcharging

• potassium hydroxide absorbs carbon dioxide from the air

• the battery becomes discharged without being connected to a load

On tank vessels with an electrically-driven capstan, the motor should be meggered periodically to test __________.

• insulation resistance

• eddy currents

• capacitance

• armature reactance

What is the maximum current allowed to be drawn from the secondary of a 2 KVA step-down transformer with a turns ratio of four to one if connected across a 440 volt line?

• 1.1 amps

• 4.5 amps

• 18.1 amps

• 22.7 amps

The apparent power in a purely inductive circuit is also known as __________.

• true power

• lead power

• induced power

• reactive power

Under which of the listed conditions can the engine room retake the throttle control from the bridge of an automated vessel?

• Any time it is deemed necessary.

• Only with the master's permission.

• After a 10 minute delay to the input command.

• Only after the throttle has been placed in stop.

Regarding battery charging rooms, ventilation should be provided __________.

• at the lowest point of the room

• horizontally near the batteries

• at the highest point of the room

• only when charging is in progress