A major difference between three-phase motors and single-phase motors is that:
A) Three-phase motors do not need any type of starting components.
B) Three-phase motors use three times as much current.
C) Three-phase motors have a laminated iron rotor.
D) Three-phase motors use three sets of starting components.
[Ques. 2] If a voltmeter shows a reading of 240 V across the thermal limit to a strip heater on an electric furnace, it indicates:
A) The limit is close, completing the circuit to the heater.
B) The limit is open, completing the circuit to the heater.
C) The limit is closed, breaking the circuit to the heater.
D) The limit is open, breaking the circuit to the heater.
[Ques. 3] Most communicating systems are wired with four wires. They are:
A) Two wires for 24 V power and two for communication.
B) Communication lines 1, 2, 3, and 4.
C) One wire for power, one for cooling, one for heating, and one for fan.
D) Power lines 1, 2, 3, and 4.
[Ques. 4] How can negative room pressure create a hazardous situation in a house with combustion appliances?
A) All the heat can be sucked out of the room through the vent.
B) Combustion products can spill into the house.
C) The appliances may burn excessively hot.
D) The gas pressure may be affected.
[Ques. 5] How is the water level in the reservoir of an ice machine maintained at the correct level?
A) A float switch
B) The reservoir is filled and sealed at the factory.
C) The reservoir has an overflow so water can safely spill over the edge.
D) The water control measures incoming water pressure.
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