Term
Power Sources
Key Topic 60: Batteries-1
3-60I1 When a lead-acid storage battery is being charged, a harmful effect to humans is:
A. Internal plate sulfation may occur under constant charging.
B. Emission of oxygen.
C. Emission of chlorine gas.
D. Emission of hydrogen gas. |
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Definition
| D. Emission of hydrogen gas. |
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Term
Power Sources
Key Topic 60: Batteries-1
3-60I2 A battery with a terminal voltage of 12.5 volts is to be trickle-charged at a 0.5 A rate. What resistance should be connected in series with the battery to charge it from a 110-V DC line?
A. 95 ohms.
B. 300 ohms.
C. 195 ohms.
D. None of these. |
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Definition
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Term
Power Sources
Key Topic 60: Batteries-1
3-60I3 What capacity in amperes does a storage battery need to be in order to operate a 50 watt transmitter for 6 hours? Assume a continuous transmitter load of 70% of the key-locked demand of 40 A, and an emergency light load of 1.5 A.
A. 100 ampere-hours.
B. 177 ampere-hours.
C. 249 ampere-hours.
D. None of these. |
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Definition
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Term
Power Sources
Key Topic 60: Batteries-1
3-60I4 What is the total voltage when 12 Nickel-Cadmium batteries are connected in series?
A. 12 volts.
B. 12.6 volts.
C. 15 volts.
D. 72 volts. |
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Definition
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Term
Power Sources
Key Topic 60: Batteries-1
3-60I5 The average fully-charged voltage of a lead-acid storage cell is:
A. 1 volt.
B. 1.2 volts.
C. 1.56 volts.
D. 2.06 volts. |
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Definition
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Term
Power Sources
Key Topic 60: Batteries-1
3-60I6 A nickel-cadmium cell has an operating voltage of about:
A. 1.25 volts.
B. 1.4 volts.
C. 1.5 volts.
D. 2.1 volts. |
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Definition
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Term
Power Sources
Key Topic 61: Batteries-2
3-61I1 When an emergency transmitter uses 325 watts and a receiver uses 50 watts, how many hours can a 12.6 volt, 55 ampere-hour battery supply full power to both units?
A. 1.8 hours.
B. 6 hours.
C. 3 hours.
D. 1.2 hours. |
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Definition
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Term
Power Sources
Key Topic 61: Batteries-2
3-61I2 What current will flow in a 6 volt storage battery with an internal resistance of 0.01 ohms, when a 3-watt, 6-volt lamp is connected?
A. 0.4885 amps.
B. 0.4995 amps.
C. 0.5566 amps.
D. 0.5795 amps. |
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Definition
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Term
Power Sources
Key Topic 61: Batteries-2
3-61I3 A ship RADAR unit uses 315 watts and a radio uses 50 watts. If the equipment is connected to a 50 ampere-hour battery rated at 12.6 volts, how long will the battery last?
A. 1 hour 43 minutes.
B. 28.97 hours.
C. 29 minutes.
D. 10 hours, 50 minutes. |
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Definition
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Term
Power Sources
Key Topic 61: Batteries-2
3-61I4 If a marine radiotelephone receiver uses 75 watts of power and a transmitter uses 325 watts, how long can they both operate before discharging a 50 ampere-hour 12 volt battery?
A. 40 minutes.
B. 1 hour.
C. 1 1/2 hours.
D. 6 hours. |
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Definition
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Term
Power Sources
Key Topic 61: Batteries-2
3-61I5 A 6 volt battery with 1.2 ohms internal resistance is connected across two light bulbs in parallel whose resistance is 12 ohms each. What is the current flow?
A. 0.57 amps.
B. 0.83 amps.
C. 1.0 amps.
D. 6.0 amps. |
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Definition
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Term
Power Sources
Key Topic 61: Batteries-2
3-61I6 A 12.6 volt, 8 ampere-hour battery is supplying power to a receiver that uses 50 watts and a RADAR system that uses 300 watts. How long will the battery last?
A. 100.8 hours.
B. 27.7 hours.
C. 1 hour.
D. 17 minutes or 0.3 hours. |
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Definition
| D. 17 minutes or 0.3 hours. |
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Term
Power Sources
Key Topic 62: Motors & Generators
3-62I1 What occurs if the load is removed from an operating series DC motor?
A. It will stop running.
B. Speed will increase slightly.
C. No change occurs.
D. It will accelerate until it falls apart. |
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Definition
| D. It will accelerate until it falls apart. |
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Term
Power Sources
Key Topic 62: Motors & Generators
3-62I2 If a shunt motor running with a load has its shunt field opened, how would this affect the speed of the motor?
A. It will slow down.
B. It will stop suddenly.
C. It will speed up.
D. It will be unaffected. |
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Definition
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Term
Power Sources
Key Topic 62: Motors & Generators
3-62I3 The expression “voltage regulation” as it applies to a shunt-wound DC generator operating at a constant frequency refers to:
A. Voltage fluctuations from load to no-load.
B. Voltage output efficiency.
C. Voltage in the secondary compared to the primary.
D. Rotor winding voltage ratio |
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Definition
| A. Voltage fluctuations from load to no-load. |
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Term
Power Sources
Key Topic 62: Motors & Generators
3-62I4 What is the line current of a 7 horsepower motor operating on 120 volts at full load, a power factor of 0.8, and 95% efficient?
A. 4.72 amps.
B. 13.03 amps.
C. 56 amps.
D. 57.2 amps. |
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Definition
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Term
Power Sources
Key Topic 62: Motors & Generators
3-62I5 A 3 horsepower, 100 V DC motor is 85% efficient when developing its rated output. What is the current?
A. 8.545 amps.
B. 20.345 amps.
C. 26.300 amps.
D. 25.000 amps. |
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Definition
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Term
Power Sources
Key Topic 62: Motors & Generators
3-62I6 The output of a separately-excited AC generator running at a constant speed can be controlled by:
A. The armature.
B. The amount of field current.
C. The brushes.
D. The exciter. |
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Definition
| B. The amount of field current. |
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