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HVAC Electrical 19 And 20 Questions And Answers With Verified Solutions Already Passed!!!
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HVAC Electrical 19 And 20 Questions And Answers With Verified Solutions Already Passed!!!
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HVAC Electrical 19 And 20 QuestionsAnd Answers With Verified Solutions
Already Passed!!!
1. A common practice in condensing units is to use a contactor with only one set of
contacts opening only one side of the power to the unit. This is to __. -
ANSWER✔✔ Provide off-cycle heat to the compressor
2. Besides maintaining pressure on the contacts for current carrying capacity, the
pressure springs have a second important function. This is to __. - ANSWER✔✔
Help obtain equal contact against the stationary contacts
3. When a contactor's coil is energized, how much resistance should be measured
between terminal "L1" and terminal "T1"? - ANSWER✔✔ Zero ohms
4. Technician "A" says that if you take a voltage reading from terminal "L1" to
terminal "T1" on a contactor whose coil is energize, you should read zero volts.
Technician "B" says that contactors can only have normally open contacts. Which
of the following statements is correct? - ANSWER✔✔ Technician "A" is correct.
Technician "B" is incorrect
5. An inherent motor protector is a __. - ANSWER✔✔ Thermally activated device
in the motor winding
6. The service factor of an electric motor is determined by __. - ANSWER✔✔
Motor's reserve capacity
7. Standards for motor overload protection are set by the __. - ANSWER✔✔
National Electrical Code
8. A solder pot is part of a __. - ANSWER✔✔ Resettable circuit breaker
9. Which of the following overload devices is not affected by ambient
temperature? - ANSWER✔✔ Magnetic
10. Most electrical problems with an electric motor are __. - ANSWER✔✔ Short
circuited windings, open windings and grounded windings.
, 11. A technician needs to check a single-phase compressor. He labels the three
terminals A, B and C and takes resistance readings of the windings. He reads 10
ohms from A to B, infinity from B to C and infinity form C to A. Identify the
terminals. - ANSWER✔✔ Cannot identify terminals: open windings
12. Technician "A" says that while checking the windings of a compressor, a
reading of 10 ohms or less from the common terminal to ground indicates that the
motor is okay. Technician "B" says that the resistance of the start winding should
always be less than the resistance of the run winding. Which of the following
statements is correct? - ANSWER✔✔ Technician "A" is incorrect. Technician "B"
is incorrect.
13. An open winding in an electric motor means that __. - ANSWER✔✔ A wire in
a winding is broken
14. Technician "A" says that a shorted winding will result in an increased current
flow through the winding. Technician "B" says that if a motor is to be replaced, a
motor with a lower horsepower rating should always be used. Which of the
following statements is correct? - ANSWER✔✔ Technician "A" is correct.
Technician "B" is incorrect
15. If the resistance of the run winding decreases the __. - ANSWER✔✔ Motor
will draw too much current while it is running
16. If a condenser fan motor ground out. It will usually __. - ANSWER✔✔ Trip a
circuit breaker to shut off the unit
17. A megger __. - ANSWER✔✔ Measures very high resistances
18. If a motor hums but does not start, there is a potential problem __. -
ANSWER✔✔ With the starting components, with an open winding, with
insufficient supply voltage.
19. The recommended way to discharge a capacitor is to __. - ANSWER✔✔ Use a
20,000-ohm 5-watt resistor that has insulated leads soldered to it
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