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WorksheetsIDA 201 final
Total questions: 100
Worksheet time: 50mins
Name
Class
Date
1.
A motor's speed is determined by ____.
a)
number of motor poles
b)
amperage
c)
voltage
d)
size
2.
Start windings are placed ____ with the run windings.
a)
slightly out of phase
b)
180 degrees out of phase
c)
in phase
d)
in series
3.
The start windings have ____.
a)
more turns than the run windings
b)
fewer turns than the run windings
c)
the same number of turns as the run windings
d)
larger diameter wire than the run windings
4.
A split-phase has a ____ winding and a ____ winding.
a)
start, run
b)
start, common
c)
common, run
d)
run, common
5.
When a general duty split-phase motor reaches approximately 75% of its operating speed, the start winding is de-energized by a ____.
a)
centrifugal switch
b)
circuit board
c)
capacitor
d)
dual voltage switch
6.
A split-phase motor that has a current relay and a start capacitor is called a(n) ____ motor.
a)
Capacitor Start, Induction Run (CSIR)
b)
Capacitor Start, Capacitor Run (CSCR)
c)
Induction Start, Induction Run (ISIR)
d)
Permanent Split Capacitor (PSC)
7.
When a Capacitor Start Induction Run (CSIR) motor is running and up to speed, what is the total capacitance acting on the motor? (Assume the run capacitor is 5 microfarads and the start capacitor is 20 microfarads, if present.)
a)
5 microfarads
b)
4 microfarads
c)
20 microfarads
d)
25 microfarads
8.
A permanent split capacitor (PSC) motor that is running and up to speed will have the start winding ____.
a)
energized
b)
de-energized
c)
in series with the run winding
d)
removed from the circuit
9.
When a Capacitor Start, Capacitor Run (CSCR) motor initially starts, what is the total capacitance acting on the motor? (Assume the run capacitor is 5 microfarads and the start capacitor is 20 microfarads, if present.)
a)
25 microfarads
b)
20 microfarads
c)
5 microfarads
d)
15 microfarads
10.
Capacitors wired in series with the starting winding provide a(n) ____.
a)
greater starting torque
b)
longer starting time
c)
aid in starting three phase motors
d)
more efficient operation at full load speed
11.
The shaded pole motor ____.
a)
has little starting torque
b)
has excessive starting torque
c)
has greater efficiency than most split-phase motors
d)
will start against a heavy starting load
12.
Three phase motors have ____.
a)
run windings only
b)
three start and three run windings for each phase
c)
one start and one run winding for each phase
d)
a start switch in each phase circuit
13.
A current magnetic relay opens and closes its contacts based on the ____.
a)
current in the run winding
b)
voltage across the run winding
c)
voltage across the start winding
d)
current in the start winding
14.
The starting device usually used on single phase, fractional horsepower motors requiring low starting torque is the ____.
a)
current relay
b)
potential relay
c)
centrifugal switch
d)
differential relay
15.
The positive temperature coefficient resistor start device is a type of ____.
a)
variable resistor
b)
capacitor
c)
switching device
d)
diode
16.
A permanent split-capacitor motor has a ____.
a)
run capacitor only
b)
start and run capacitor
c)
start capacitor only
d)
split phase capacitor
17.
The heavier the load on an operating motor, the greater the amount of slip.
a)
True
b)
Fasle
18.
The contact(s) in a potential type starting relay are normally closed.
a)
True
b)
Fasle
19.
The microfarad rating of the run capacitor is much lower than that of the start capacitor for any given motor application.
a)
True
b)
Fasle
20.
The contact(s) in a current type starting relay are normally closed.
a)
False
b)
True
21.
The resistances of the windings in a three phase motor are all equal.
a)
True
b)
False
22.
The ______________ is a winding that, when energized, will generate a magnetic field as there will be current flowing through it.
a)
Stator
b)
Potential
c)
Microfarad
d)
Capacitor
23.
The rotating portion of an electric motor is called the ____________________.
a)
Rotor
b)
Cage
c)
Phase
d)
Capacitor
24.
The coil of a potential relay has ____________________ resistance.
a)
High
b)
Low
c)
Mild
d)
No
25.
On a potential relay, the coil is connected between terminals 2 and ____________________.
a)
5
b)
1
c)
3
d)
4
26.
When not air cooled, the heat generated by the motor in a hermetic motor-compressor assembly is removed by what?
a)
Refrigerant Vapor
b)
Refrigerant liquid
c)
Water
d)
Water-Vapor
27.
Motors have two different current ratings, the full-load or rated amps (FLA or RLA) and the ____________.
a)
locked-rotor amps
b)
cycles per second
c)
running-load amps
d)
induction current
28.
The difference between the motor's calculated and actual speed is called _______.
a)
motor slip
b)
running speed
c)
motor differential
d)
synchronous speed
29.
The _________ is used with some motors to open the start windings after the motor has started.
a)
electronic relay
b)
phase angle
c)
run capacitor
d)
start capacitor
30.
The amount by which the current leads or lags the voltage is called phase angle.
a)
true
b)
false
31.
When enough back EMF has built up, called _______ voltage, the contacts between terminals 1 and 2 of a potential relay will open.
a)
pick-up
b)
coil
c)
rated
d)
potential
32.
A positive temperature coefficient resistor (PTCR) ____________.
a)
increases its resistance as its temperature increases
b)
opens a set of contacts when the main coil is magnetized
c)
increases its resistance when its temperature decreases
d)
decreases its resistance when its temperature increases
33.
The resistance between the terminals of a three-phase compressor motor __________.
a)
is the same
b)
should be within 20% of each other
c)
should add up to the locked-rotor amperage
d)
will vary from one terminal to the next
34.
The two basic types of converters are the phase-controlled rectifier and the diode bridge rectifier.
a)
true
b)
false
35.
The two most common operating voltages for residential equipment are:
a)
115v and 230v
b)
24v and 240v
c)
115v and 277v
d)
277v and 480v
36.
Which of the following devices may be wired into the starting circuit of a motor to improve the starting torque?
a)
a start capacitor
b)
another winding
c)
a thermostat
d)
a winding thermostat
37.
Which of the following devices may be wired into the running circuit of a motor to improve the running efficiency?
a)
a run cap
b)
a start cap
c)
both a run and start cap
d)
none of the above
38.
Two types of motors most commonly used in hermetic compressors are:
a)
Permanent split-capacitor and split-phase
b)
Shaded-pole and permanent split-capacitor
c)
Capacitor-start, capacitor run and shaded-pole
d)
Split-phase and shaded-pole
39.
Which of the following voltages are not safe for a 208-V motor to operate?
a)
170 Volts and 238 Volts
b)
170 Volts
c)
238 Volts
d)
220 Volts
40.
If the voltage supplied to the motor is well below the motor rated voltage, the current draw will be ____ it should be.
a)
higher than
b)
lower than
c)
the same as
d)
in reverse polarity than
41.
The voltage tolerance of a standard electric motor is ____.
a)
+10% -10%
b)
+5% -10%
c)
+10% -5%
d)
+15% -15%
42.
The locked-rotor amperage is normally ____ times as great as the run-load amperage.
a)
5
b)
2
c)
3
d)
10
43.
The motor that should be used in a potentially wet area is a(n) ____ motor.
a)
drip proof
b)
enclosed
c)
explosion proof
d)
open
44.
A sleeve bearing would typically be used in a motor that operates with a ____.
a)
light load and where noise is a factor
b)
heavy load and where noise is a factor
c)
heavy load in a dirty atmosphere
d)
heavy load in a moist atmosphere
45.
A slotted screw at the bottom of the bearing housing is called a ____.
a)
relief plug
b)
purge screw
c)
drain plug
d)
retaining screw
46.
A direct-drive motor is usually connected to a load with a ____.
a)
coupling
b)
cradle mount
c)
rigid base mount
d)
pulley
47.
Grounding straps are required on resilient mounted motors to ____.
a)
ground the motor in case of winding failure
b)
prevent rotation of the motor in the mount
c)
help reduce motor vibration transfer to the object on which the motor is mounted
d)
act as the position for locating the motor leads
48.
A motor can burn out if the supply voltage is either too high or too low.
a)
True
b)
False
49.
A drip-proof motor is designed to prevent any lubricating oil from leaving any of the bearings.
a)
False
b)
True
50.
Regardless of the type of motor or application, the motor bearings require yearly lubrication.
a)
False
b)
True
51.
There is a definite relationship between the speed of the motor and the speed of the blower.
a)
True
b)
False
52.
The alternating current frequency supplied by the power companies in the United States is ____________________ hertz.
a)
60
b)
80
c)
50
d)
120
53.
The vertical condenser fan is trying to fly downward into the unit to push air out the top, which puts a real load on the end of the bearing, called the ____________________ surface.
a)
Thrust
b)
Rust
c)
Ground
d)
Drive
54.
In order to be electrically safe, a motor that is set in a "resilient" mount, must have a(n) ____________________.
a)
Ground strap
b)
Electrical strap
c)
Voltage strap
d)
Drive strap
55.
Whenever possible, when changing a motor, the _________________________ should be obtained.
a)
Exact replacement
b)
Does not matter
c)
Similar replacement
d)
Drive replacement
56.
The device that transfers the motor's energy to the driven component is called the _________________________.
a)
drive mechanism
b)
power supply
c)
ground strap
d)
transformer
57.
T/F: By taking amperage readings at start-up and while the motor is operating under load and comparing these readings with those on the motor nameplate, the technician can determine whether the motor is operating within its design parameters.
a)
True
b)
False
58.
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 ____.
a)
provide off-cycle heat to the compressor
b)
reduce the cost of the contactor
c)
make it easier to wire the unit
d)
teach the service technician not to put hands in the unit with the power on
59.
When a contactor's coil is energized, how much resistance should be measured between terminal "L1" and terminal "T1"?
a)
zero ohms
b)
50-3000 ohms
c)
5000-6000 ohms
d)
infinite
60.
The service factor of an electric motor is determined by ____.
a)
motor's reserve capacity
b)
National Electrical Code
c)
National Electrical Manufacturers Association code
d)
the required wire size supplying power to the motor
61.
Standards for motor overload protection are set by the ____.
a)
National Electrical Code
b)
United States Department of Transportation
c)
Environmental Protection Agency
d)
American National Standards Institute
62.
A solder pot is part of a ____.
a)
resettable circuit breaker
b)
one-time fuse
c)
time-delay fuse
d)
plumber's tool kit
63.
Which of the following overload devices is not affected by ambient temperature?
a)
magnetic
b)
solder pot
c)
bimetal
d)
time-delay fuse
64.
The locked rotor amperage, LRA, of a motor is typically five times higher than the full load amperage, FLA, of the motor and can be as high as seven times the FLA.
a)
True
b)
False
65.
A set of contacts are closed when the relay is energized. These contacts are classified as normally closed.
a)
False
b)
True
66.
Auxiliary contacts are usually rated at a lower amperage than the contactor's primary contacts.
a)
True
b)
False
67.
Contactor contacts that are badly pitted can cause the motor to burn out.
a)
True
b)
False
68.
A sure sign of contact failure is discoloration on the contact surfaces.
a)
False
b)
True
69.
Bimetal and solder pot overload devices are thermally operated.
a)
True
b)
False
70.
Magnetic overload devices are the most accurate type of device for electrical protection.
a)
True
b)
False
71.
If a normally operating motor draws 75 amps on startup, it will most likely draw ____________________ amps when running.
a)
15
b)
10
c)
12
d)
17
72.
The best way to repair a defective relay is by ____________________.
a)
Replacemnet
b)
Fixing
c)
Measuring
d)
Conducting
73.
The most common material used on the surface of contacts is ____________________.
a)
Silver
b)
Gold
c)
Brass
d)
Aluminum
74.
If a relay starts the indoor fan in the cooling mode of a central air-conditioning system, it must be able to withstand the ____________________ of the fan motor on start-up.
a)
Inrush current
b)
Outrush current
c)
Voltage
d)
Resistance
75.
The best way to repair a large contactor is by the replacement of component parts.
a)
True
b)
False
76.
Define a relay.
a)
A relay is a magnetically controlled set of contacts that are not replaceable.
b)
A relay is a electrically controlled set of contacts that are not replaceable.
c)
A relay is a magnetically controlled set of contacts that are replaceable.
d)
A relay is a electrically controlled set of contacts that are replaceable.
77.
T/F: Why should a technician not file the rough surfaces of a contactor's contacts?
The base metal will be exposed and the contacts will deteriorate.
a)
True
b)
False
78.
Define a contactor.
a)
A contactor is a magnetically controlled set of contacts that may be rebuilt.
b)
A contactor is a electrically controlled set of contacts that may be rebuilt.
c)
A contactor is a magnetically controlled set of contacts that can not be rebuilt.
d)
A contactor is a electrically controlled set of contacts that can not be rebuilt.
79.
T/F: Why is a starter equipped with overload protection when the circuit already has a fuse or circuit breaker?
The fuse or circuit breaker protects the individual component, not the entire circuit.
a)
False
b)
True
80.
What effect would a loose connection have on a solder pot overload device?
a)
Heat produced by the loose connection can cause the solder pot to trip.
b)
Voltage produced by the loose connection can cause the solder pot to trip.
c)
Heat produced by the loose connection can cause the solder pot to heat.
d)
Voltage produced by the loose connection can cause the solder pot to heat.
81.
Most electrical problems with an electric motor are ____.
a)
short circuited windings. open windings, and grounded windings
b)
short circuited windings, closed windings, and grounded windings
c)
all of the above
d)
none of the above
82.
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 from "C" to "A." Identify the terminals.
a)
Cannot identify terminals: open winding
b)
Cannot identify terminals: winding grounded
c)
A: common B: start C: run
d)
A: start B: run C: common
83.
An open winding in an electric motor means that ____.
a)
a wire in a winding is broken
b)
the winding is making contact with the motor frame
c)
one winding is making contact with another winding
d)
the centrifugal switch to the start winding is open
84.
If the resistance of the run winding decreases, the ____.
a)
motor will draw too much current while it is running
b)
motor probably will not start
c)
centrifugal starting switch will not start the motor
d)
load on the motor is probably too great
85.
If a condenser fan motor grounds out, it will usually ____.
a)
trip a circuit breaker to shut off the unit
b)
keep running as the current is only going to ground
c)
run a little faster because the amperage draw will increase
d)
cause the evaporator to ice up
86.
If a motor hums but does not start, there is a potential problem ____.
a)
all of the above
b)
with the starting components
c)
with an open winding
d)
with insufficient supply voltage
87.
The wiring and connectors that carry the power to a motor must be in good condition. When a connection becomes loose, oxidation of the copper wire occurs. The oxidation ____.
a)
acts as an electrical resistance and causes the connection to heat more
b)
has no effect on the electrical connection
c)
decreases the resistance
d)
none of the above
88.
What is the best method to repair a fractional horsepower motor that has bad bearings?
a)
Replace the entire motor.
b)
Replace the bearings.
c)
Replace the bearings and shaft.
d)
Add a capacitor to the circuit for added torque.
89.
Belt tension will not have any affect on the wear of the bearings.
a)
False
b)
True
90.
Pulleys must be in proper alignment or belt and bearing wear will occur.
a)
True
b)
False
91.
Open winding will not affect the resistance reading of the start winding as well as the resistance reading between the Run and Start terminals.
a)
False
b)
True
92.
If the resistance of the run winding is lowered, the imbalance in magnetic fields between the start and the run winding will be increased, and the starting torque of the motor will actually increase.
a)
True
b)
False
93.
If a resilient-mounted motor develops a short to the frame, the technician can simply cut the ground strap wire as a permanent repair.
a)
False
b)
True
94.
Before testing a run or start capacitor with an ohmmeter, the capacitor should be discharged with a 20,000-ohm 5-watt resistor.
a)
True
b)
Fasle
95.
The electrical components for a fully welded hermetic compressor are checked at the disconnect box for the compressor unit.
a)
False
b)
True
96.
Two common reasons for motor failure are improper pulley alignment and over-tightened belts.
a)
True
b)
False
97.
A motor has four leads out of it: two red and two black. The resistance between the red leads is 3 ohms. The resistance between the black leads is 5 ohms. The black leads are connected to the ____________________ winding.
a)
Start
b)
Run
c)
Common
d)
False
98.
How can a technician tell if a belt is slipping?
a)
A low force reading indicates that the belt is too loose.
b)
A high force reading indicates that the belt is too loose.
c)
A low force reading indicates that the belt is too tight.
d)
A high force reading indicates that the screw are too loose.
99.
If the needle of an ohmmeter used to check a capacitor goes to the 0 ohms reading and does not move, this would indicate that the capacitor is ____________________.
a)
Shorted
b)
Open
c)
Closed
d)
Neutral
100.
How can a technician determine if a run capacitor has overheated?
a)
It has Swelled
b)
It is Cold
c)
It isHot
d)
It will Shrink
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