Electricidad 8

For practical purposes, in a simple series circuit employing two resistors, the largest voltage drop will occur across the resistor which has  __________.

• a partial short circuit

• the greatest resistance

• a resistance equal to the other

• less resistance than the other resistor

A short in the shunt field of a DC motor is best located by __________.

• visual inspection of the commutator

• applying AC voltage to each field coil and measuring the voltage drop across each field coil

• using a growler and hacksaw blade

• isolating each coil from the others and using a megohmmeter

In the illustration shown, when is the solenoid valve installed?

• Whenever a backpressure regulator is present.

• When the "energy saving" mode is present.

• Only when the ice maker option is installed.

• All of the above.

In a three-wire, 230/115 volt DC system, the potential between neutral and negative is __________.

• 0 volts

• 115 volts

• 230 volts

• 460 volts

What is represented by the electric symbol figure "D" in the illustration?

• Fuse

• Plug-in contact resistor

• Variable capacitor

• Electrolytic capacitor

What type of electrical control diagram is shown in the illustration?

• schematic diagram

• wiring diagram

• logic  diagram

• one line diagram

An electrical component is connected across a 120 volt 60 hertz AC supply. What is the current drawn by the component if the impedance is 200 ohms?

• 0.01 amperes

• 0.60 amperes

• 1.67 amperes

• 100 amperes

Which of the methods listed is used to maintain the division of load between two compound-wound, DC generators operating in parallel?

• The shunt fields are interconnected.

• The shunt field rheostats are interconnected.

• The series fields of both generators are connected in series.

• The equalizer connection parallels the series fields of all machines.

While on watch in the engine room, you are setting up to parallel alternators. The switchboard has a synchroscope and synchronizing lamps. If the synchoscope is broken, which of the steps listed is the most essential before an alternator can be paralleled with the bus?

• The breaker should be closed when one synchronizing lamp is dark and the other is bright.

• The breaker should be closed when both synchronizing lamps are bright.

• The frequency meter should be used to determine that the incoming alternator frequency is slightly higher than the bus.

• A portable phase sequence  indicator must be used to verify the information from the lamps.

Which of the following statements is correct regarding the use of a multimeter when directly measuring current?

• It must be connected in series with the circuit.

• You should always start with the lowest range until a suitable reading is obtained.

• The indicating needle is deflected from left to right regardless of polarity.

• An external shunt is generally utilized where current is less than 10 amperes.