Unlock document.
This document is partially blurred.
Unlock all pages and 1 million more documents.
Get Access
80)
80)
The range of an electric meter describes:
A)
The number of different functions the meter has.
B)
The meter's price point.
C)
How low and high the meter will read for each function.
D)
Whether a meter is analog or digital.
Answer:
C
Explanation:
A)
B)
C)
D)
81)
81)
A wattmeter is connected to a circuit with 120 V, 10 A, and a power factor of 91.7%. Its reading is:
A)
1,000 W.
B)
1,300 W.
C)
1,200 W.
D)
1,100 W.
Answer:
D
Explanation:
A)
B)
C)
D)
82)
82)
A technician uses an ohmmeter to check resistance and for a complete path in the electrical circuit,
also known as:
A)
Amperage.
B)
Reactance.
C)
Capacitance.
D)
Continuity.
Answer:
D
Explanation:
A)
B)
C)
D)
83)
83)
Wattmeters read true power in a circuit. This can be expressed by what equation?
A)
Power = amps × voltage × power factor
B)
Power = amps × volts
C)
Power = ohms divided by volts
D)
Power = ohms × volts × power factor
Answer:
A
Explanation:
A)
B)
C)
D)
21
84)
84)
What three specifications help determine whether or not a particular meter is appropriate for a
particular use?
A)
Case, max reading, and display
B)
Switch positions, display, and case
C)
Range, resolution, and accuracy
D)
Max volts, max amps, and max resistance
Answer:
C
Explanation:
A)
B)
C)
D)
85)
85)
Where does the current come from for resistance measurements on an ohmmeter?
A)
The battery inside the meter
B)
The ohmmeter uses induction to produce a small electric current using the magnetic field
surrounding the wire it is testing.
C)
The meter uses a small amount of current from the circuit it is testing.
D)
No current is required to move the needle on an analog ohmmeter.
Answer:
A
Explanation:
A)
B)
C)
D)
86)
86)
This test instrument reads current in an electrical circuit.
A)
Ohmmeter
B)
Ammeter
C)
Voltmeter
D)
Oscilloscope
Answer:
B
Explanation:
A)
B)
C)
D)
87)
87)
What is the operating principle of an analog voltmeter?
A)
Current passes through a series of lights, which indicates the voltage level by turning on the
correct lights.
B)
Current passes through a coil, which creates magnetism that moves a needle.
C)
Electronic chips are used to calculate the voltage level.
D)
Analog meters are no longer manufactured.
Answer:
B
Explanation:
A)
B)
C)
D)
22
88)
88)
Which of the following can multimeters be used to measure?
A)
Current, pressure, and temperature
B)
Temperature, resistance, and distance
C)
Voltage, temperature, and pressure
D)
Voltage, current, and resistance
Answer:
D
Explanation:
A)
B)
C)
D)
89)
89)
What should you look for on the meter besides a CAT rating?
A)
An EPA approval
B)
A DOE approval
C)
A certification from an independent laboratory
D)
An endorsement from a well-known technician
Answer:
C
Explanation:
A)
B)
C)
D)
90)
90)
When is it important to match the polarity of the meter leads to the polarity of the circuit being
tested?
A)
When reading DC voltage
B)
When reading AC voltage
C)
With all readings
D)
When reading resistance
Answer:
A
Explanation:
A)
B)
C)
D)
91)
91)
When choosing an electric meter, it is important to use the proper category rating:
A)
For either the meter or the leads–neither is necessary.
B)
For both the meter and the leads.
C)
For the meter leads.
D)
For the meter.
Answer:
B
Explanation:
A)
B)
C)
D)
23
92)
92)
When measuring voltage with an analog meter, what should the technician do?
A)
Set the meter to the lowest range.
B)
The technician should not attempt to read the voltage.
C)
Set the meter to the highest range.
D)
Any range will work for a starting point, and then adjust from there.
Answer:
C
Explanation:
A)
B)
C)
D)
93)
93)
What category of electric meter is intended for measurement at the electric meter base?
A)
Category I
B)
Category III
C)
Category IV
D)
Category II
Answer:
C
Explanation:
A)
B)
C)
D)
94)
94)
Which of the following systems would be most likely to produce a power waveform that would
require a true RMS meter to accurately measure?
A)
A shaded-pole motor controlled by a relay
B)
An electric strip heater controlled by a contactor
C)
A three-phase motor controlled by a variable-frequency drive
D)
An incandescent light controlled by a toggle switch
Answer:
C
Explanation:
A)
B)
C)
D)
95)
95)
How can a technician determine what the proper PPE is for a particular application?
A)
Ask someone near the machine you are going to test.
B)
Read NFPA Standard 70E.
C)
Read the instructions on the electrical panel.
D)
Safety glasses work for most jobs.
Answer:
B
Explanation:
A)
B)
C)
D)
24
96)
96)
With its leads on either side of a switch, a voltmeter reads 120 V. This indicates that:
A)
The switch is open, allowing 120 V to pass through.
B)
The switch is closed, so voltage cannot pass through.
C)
The switch is open, so voltage cannot pass through.
D)
The switch is closed, allowing 120 V to pass through.
Answer:
C
Explanation:
A)
B)
C)
D)
97)
97)
What is a common application for data logging instruments?
A)
Producing a printout of all tests performed to give the customer
B)
Identifying intermittent problems
C)
Identifying data entry points in a direct digital control network
D)
Recording all tests a service technician performs for later audit and verification
Answer:
B
Explanation:
A)
B)
C)
D)
98)
98)
How are inline ammeters connected to read the current in a circuit?
A)
Any connection to the circuit will give the same reading.
B)
They are connected in parallel with the load.
C)
One lead is connected to the load and the other lead is connected to ground.
D)
They are connected in series with the load.
Answer:
D
Explanation:
A)
B)
C)
D)
99)
99)
How are voltmeters connected to read the voltage drop across a load in a circuit?
A)
Any connection to the circuit will give the same reading.
B)
One lead is connected to the load, and the other lead is connected to ground.
C)
Voltmeters are connected in series with the load.
D)
Voltmeters are connected in parallel with the load.
Answer:
D
Explanation:
A)
B)
C)
D)
25
100)
100)
One advantage of digital meters is:
A)
There is no need to interpret the scale.
B)
They cannot be damaged by improper use.
C)
They do not require batteries like analog meters do.
D)
They are preferable for fluctuating readings.
Answer:
A
Explanation:
A)
B)
C)
D)
101)
101)
What type of measurements require a true RMS meter to obtain accurate results?
A)
Nonlinear, electronic switching loads
B)
Strip heater current
C)
Shaded-pole motor current
D)
Linear alternating current loads
Answer:
A
Explanation:
A)
B)
C)
D)
102)
102)
An ohmmeter is set on continuity and beeps when the leads are connected to a circuit. This
indicates that:
A)
The circuit is broken.
B)
The circuit has a high resistance.
C)
The circuit path is complete.
D)
The circuit is not grounded.
Answer:
C
Explanation:
A)
B)
C)
D)
103)
103)
What type of meter do HVACR technicians use to measure current?
A)
A solenoid meter
B)
A clamp-on ammeter
C)
A noncontact voltage detector
D)
An in-line wattmeter
Answer:
B
Explanation:
A)
B)
C)
D)
26
104)
104)
When checking to make sure a circuit is de-energized, you should test:
A)
With a slight touch of the back of your hand.
B)
By spitting on the contact to see if it sizzles.
C)
Between any two possible voltage points.
D)
Voltage to ground.
Answer:
D
Explanation:
A)
B)
C)
D)
105)
105)
The safest way to use a meter while testing for voltage is to:
A)
Hold it loosely in case it becomes energized so you can drop it.
B)
Rest the meter on something; do not hold it.
C)
Hold the meter in your mouth and a lead in each hand.
D)
Hold it securely to make certain it won't slip.
Answer:
B
Explanation:
A)
B)
C)
D)
106)
106)
Two common pressure-sensing devices used in pressure controls are:
A)
Sail switch and warp switch.
B)
Strain gauge and expansion tube.
C)
The bellows and the diaphragm.
D)
Capacitive transducer and thermistor.
Answer:
C
Explanation:
A)
B)
C)
D)
107)
107)
What is the most common form of switching used for mechanical thermostats?
A)
Mercury bulb
B)
Magnets
C)
Spring and bellows
D)
Warped discs
Answer:
A
Explanation:
A)
B)
C)
D)
27
108)
108)
What is used as the sensing element in a mechanical humidistat?
A)
A coiled piece of hygroscopic metal
B)
A nylon ribbon or hair
C)
A sensing bulb filled with water
D)
Mercury
Answer:
B
Explanation:
A)
B)
C)
D)
109)
109)
A triac can be described as:
A)
Two silicon-controlled rectifiers (SCR) in series.
B)
Three silicon-controlled rectifiers (SCR) in series.
C)
Three silicon-controlled rectifiers (SCR) in parallel.
D)
Two silicon-controlled rectifiers (SCR) in parallel.
Answer:
D
Explanation:
A)
B)
C)
D)
110)
110)
Heat pump thermostats generally require two stages of heating in order to control:
A)
The indoor and outdoor sections.
B)
The auxiliary heat.
C)
The compressor and outdoor fan.
D)
The first- and second-stage heat strips.
Answer:
B
Explanation:
A)
B)
C)
D)
111)
111)
One advantage relay logic systems have over solid-state logic systems is that:
A)
They are faster.
B)
They are not affected by noisy power signals.
C)
They consume less power.
D)
They can control more functions.
Answer:
B
Explanation:
A)
B)
C)
D)
28
112)
112)
What device can best be described as an electrically operated switch?
A)
A relay
B)
A transformer
C)
A transducer
D)
A fuse
Answer:
A
Explanation:
A)
B)
C)
D)
113)
113)
A silicon-controlled rectifier (SCR):
A)
Can be turned on and off like an electronically controlled switch.
B)
Turns AC voltage to DC voltage.
C)
Turns DC voltage to AC voltage.
D)
Increases or decreases alternating current voltage.
Answer:
A
Explanation:
A)
B)
C)
D)
114)
114)
This component uses the properties of AC induction to step up or step down voltage for particular
HVAC applications.
A)
Start capacitor
B)
Transformer
C)
Contactor
D)
Diode
Answer:
B
Explanation:
A)
B)
C)
D)
115)
115)
The difference between the cut-out and cut-in points of a control is known as:
A)
Spread.
B)
Range.
C)
Differential.
D)
Setpoint.
Answer:
C
Explanation:
A)
B)
C)
D)
29
116)
116)
How does a remote bulb thermostat work?
A)
An electronic sensor in the bulb sends signals back to the thermostat.
B)
The metal in the bulb expands and contracts with temperature changes.
C)
The remote bulb communicates with the thermostat using wireless communication.
D)
Pressure in the bulb rises and falls with temperature.
Answer:
D
Explanation:
A)
B)
C)
D)
117)
117)
A system that controls loads by opening and closing electrically operated mechanical switches is
described as:
A)
Pneumatic logic.
B)
A relay logic.
C)
Solid-state logic.
D)
Modulating logic.
Answer:
B
Explanation:
A)
B)
C)
D)
118)
118)
When do normally closed relay contacts close?
A)
When they receive power
B)
They are always closed because they are closed contacts.
C)
When the relay coil is de-energized
D)
When the relay coil is energized
Answer:
C
Explanation:
A)
B)
C)
D)
119)
119)
Semiconductors are primarily used in:
A)
Pneumatic controls.
B)
Electronic controls.
C)
Mechanical control linkages.
D)
Electromechanical controls.
Answer:
B
Explanation:
A)
B)
C)
D)
30
120)
120)
The thermostats on most residential air-conditioning systems are:
A)
Low-voltage thermostats.
B)
Line voltage thermostats.
C)
Wireless communicating thermostats.
D)
Milli-voltage thermostats.
Answer:
A
Explanation:
A)
B)
C)
D)
121)
121)
The electrical switching in an electronic thermostat is often done by:
A)
Batteries.
B)
A mercury bulb.
C)
Small relays.
D)
Resistors.
Answer:
C
Explanation:
A)
B)
C)
D)
122)
122)
When the third color band is silver, it represents:
A)
The first two digits of the resistor value.
B)
The multiplier for the resistor value.
C)
The resistor tolerance.
D)
The color frequencies of the waveform.
Answer:
B
Explanation:
A)
B)
C)
D)
123)
123)
What is the purpose of staging thermostats?
A)
To control the temperature of control equipment in theaters
B)
To allow systems to operate at reduced capacity
C)
To control the temperature of theaters
D)
To operate two different pieces of equipment with a single thermostat
Answer:
B
Explanation:
A)
B)
C)
D)
31
124)
124)
When do normally open relay contacts close?
A)
They cannot close because they are open contacts.
B)
When the relay coil is de-energized
C)
When the relay coil is energized
D)
When they receive power
Answer:
C
Explanation:
A)
B)
C)
D)
125)
125)
This electrical component allows current to flow in only one direction and operates similar to a
check valve.
A)
Bleed resistor
B)
Diode
C)
Semiconductor
D)
Capacitor
Answer:
B
Explanation:
A)
B)
C)
D)
126)
126)
The instructions ona low-pressure switch read "cut-out is cut-in less differential." To set the
switch to cut-out at 30 psig:
A)
Set the cut-in at 45 psig and the differential at 20 psi.
B)
Set the cut-in at 45 psig and the differential at 15 psi.
C)
Set both the cut-in psig and differential at 20 psi.
D)
Set the differential at 45 psi and the cut-in at 15 psig.
Answer:
B
Explanation:
A)
B)
C)
D)
127)
127)
Low-voltage thermostats normally operate on:
A)
120 V.
B)
480 V.
C)
24 V.
D)
277 V.
Answer:
C
Explanation:
A)
B)
C)
D)
32
128)
128)
Line voltage thermostats normally operate on:
A)
24 V.
B)
480 V.
C)
277 V.
D)
120 V.
Answer:
D
Explanation:
A)
B)
C)
D)
129)
129)
A fuse protects an electrical circuit by:
A)
Using a material that limits the amount of current that can pass through the fuse due to the
increase in the material's resistance.
B)
Using a heat motor that operates an imbedded set of contacts to open the circuit.
C)
Melting when excessive current flows through it, opening the circuit.
D)
Limiting the voltage that can flow through the fuse.
Answer:
C
Explanation:
A)
B)
C)
D)
130)
130)
A close-on-rise pressure switch has a cut-in of 50 psig and a differential of 15 psi. What is the
cut-out?
A)
15 psig
B)
65 psig
C)
50 psig
D)
35 psig
Answer:
D
Explanation:
A)
B)
C)
D)
131)
131)
Overloads are designed to protect against:
A)
Excessive resistance.
B)
Excessive countercyclical electron rotation.
C)
Excessive current.
D)
Excessive voltage.
Answer:
C
Explanation:
A)
B)
C)
D)
33
132)
132)
The primary winding of a 120 V transformer has 200 turns. The secondary winding has 20 turns.
What is the secondary winding voltage?
A)
60 V
B)
24 V
C)
12 V
D)
1,200 V
Answer:
C
Explanation:
A)
B)
C)
D)
133)
133)
A system that uses electronic components with no moving parts can be described as:
A)
Solid-state logic.
B)
Relay logic.
C)
Modulating logic.
D)
Pneumatic logic.
Answer:
A
Explanation:
A)
B)
C)
D)
134)
134)
The two principal parts of an AC induction motor are the:
A)
Housing and capacitor.
B)
Bearing and sleeve.
C)
Coil and bushing.
D)
Rotor and stator.
Answer:
D
Explanation:
A)
B)
C)
D)
135)
135)
The proper way to discharge a capacitor is to:
A)
Connect a jumper wire across the terminals.
B)
Apply 230 V to the terminals for a short period of time.
C)
Short across the terminals with a large, insulated screwdriver.
D)
Connect a bleed resistor across the terminals.
Answer:
D
Explanation:
A)
B)
C)
D)
34
136)
136)
The rotation of an ECM motor is determined by:
A)
The internal motor wiring.
B)
The module program.
C)
The polarity of the power into the motor.
D)
The polarity of the start winding.
Answer:
B
Explanation:
A)
B)
C)
D)
137)
137)
The start capacitor for fractional horsepower, open-type capacitor start motors is removed from
the circuit by:
A)
A centrifugal switch.
B)
The normally closed points on the motor relay.
C)
A normally open, manual pushbutton switch.
D)
A Hall effect sensing switch.
Answer:
A
Explanation:
A)
B)
C)
D)
138)
138)
The rotor of an ECM motor is composed of:
A)
Layers of laminated soft iron.
B)
A solid bronze casting.
C)
Permanent magnets.
D)
Copper windings coiled around layers of laminated soft iron.
Answer:
C
Explanation:
A)
B)
C)
D)
139)
139)
The speed of an AC induction motor is determined by:
A)
The number of poles and the frequency of the alternating current.
B)
The number of turns in the motor winding.
C)
The voltage applied to the armature.
D)
The voltage of the field windings.
Answer:
A
Explanation:
A)
B)
C)
D)
35
140)
140)
Variable-frequency drives (VFD) reduce the speed of AC motors by:
A)
Applying an adjustable magnetic brake to the motor.
B)
Controlling the voltage available to the motor, like a light dimmer.
C)
Controlling the frequency (Hz) of the power to the motor.
D)
Limiting the current to the motor.
Answer:
C
Explanation:
A)
B)
C)
D)
141)
141)
Why are capacitors rated at higher voltages than the unit line voltage?
A)
They are overrated as a safety measure.
B)
Capacitors increase the voltage to the motor.
C)
They are charged with a high voltage at the factory.
D)
Charging and discharging in series with an inductive load subjects them to high voltage.
Answer:
D
Explanation:
A)
B)
C)
D)
142)
142)
To reverse the rotation of a three-phase motor:
A)
Reverse any two power legs going to the motor.
B)
Reverse the polarity of the start winding.
C)
It is necessary to disassemble the motor.
D)
Three-phase motors cannot be reversed.
Answer:
A
Explanation:
A)
B)
C)
D)
143)
143)
The start capacitor is removed from the CSCR circuit by:
A)
A normally open, manual pushbutton switch.
B)
A starting relay.
C)
A high-pressure switch.
D)
The normally closed points on the compressor contactor.
Answer:
B
Explanation:
A)
B)
C)
D)
36
144)
144)
What happens when a three-phase motor tries to operate on only two legs of power?
A)
The motor current decreases.
B)
The motor turns 2/3 as fast
C)
The motor strength increases.
D)
The motor overheats.
E)
The motor strength is reduced to approximately two-thirds its rating.
Answer:
D
Explanation:
A)
B)
C)
D)
E)
145)
145)
The rotor consists of:
A)
A solid cast aluminum cylinder that is highly machined.
B)
Aluminum bars mounted on a laminated soft iron core.
C)
A solid cast iron cylinder that is highly machined.
D)
Soft iron bars mounted in a laminated aluminum core.
Answer:
B
Explanation:
A)
B)
C)
D)
146)
146)
How does the rotor of an AC induction motor receive current?
A)
Rotor current is induced by the rotor magnetic field.
B)
The rotor is precharged at the factory.
C)
The rotor is powered by internal batteries.
D)
Rotor current passes through brushes to the rotor.
Answer:
A
Explanation:
A)
B)
C)
D)
147)
147)
Compared to the stator's magnetic field, the rotor's magnetic field is:
A)
Opposite in polarity.
B)
Fixed instead of varying.
C)
Much stronger.
D)
Similar in polarity.
Answer:
A
Explanation:
A)
B)
C)
D)
37
148)
148)
The run capacitor of a permanent split capacitor (PSC) motor:
A)
Remains in the circuit while the motor operates.
B)
Is optional.
C)
Boosts the motor line voltage.
D)
Drops out of the circuit after the motor starts.
Answer:
A
Explanation:
A)
B)
C)
D)
149)
149)
The magnetic field of the stator is:
A)
Opposite in polarity as the rotor magnetic field.
B)
Permanently set at the factory.
C)
Always oriented to the north.
D)
The same polarity as the rotor magnetic field.
Answer:
A
Explanation:
A)
B)
C)
D)
150)
150)
Compared to PSC motors, brushless DC motors:
A)
Inexpensive, but also less efficient.
B)
More efficient, but not well suited for variable-speed applications.
C)
More efficient and better suited for variable-speed applications.
D)
Are less efficient, but well suited for variable-speed applications.
Answer:
C
Explanation:
A)
B)
C)
D)
151)
151)
The two common winding configurations for three-phase motors are:
A)
Rho and sigma.
B)
Alpha and omega.
C)
Single-phase and three-phase.
D)
Wye and delta.
Answer:
D
Explanation:
A)
B)
C)
D)
38
152)
152)
This type of AC motor is characterized by low starting torque and is suitable for light applications
such as refrigerator evaporator motors.
A)
CSIR
B)
Split phase
C)
Shaded pole
D)
PSC
Answer:
C
Explanation:
A)
B)
C)
D)
153)
153)
The line current of a delta-wound three-phase motor is:
A)
1.73 times the phase current.
B)
3 times the phase current.
C)
Equal to the phase current.
D)
1.5 times the phase current.
Answer:
A
Explanation:
A)
B)
C)
D)
154)
154)
AC induction motor speed is determined by the current frequency (Hz) and the number of:
A)
Motor poles.
B)
Speed taps.
C)
Start windings.
D)
Run windings.
Answer:
A
Explanation:
A)
B)
C)
D)
155)
155)
The capacitor in a permanent split capacitor (PSC) motor:
A)
Is in parallel with the line voltage power supply.
B)
Is an internal component that is wired in at the factory.
C)
Is in series with the start winding.
D)
Is in series with the run winding.
Answer:
C
Explanation:
A)
B)
C)
D)
39
156)
156)
Compared to the run winding, the start winding is constructed of:
A)
Higher flux density, random molecular alignment wire.
B)
Smaller gauge wire than the run winding.
C)
Larger gauge wire than the run winding.
D)
The same gauge wire as the run winding.
Answer:
B
Explanation:
A)
B)
C)
D)
157)
157)
The two electrical connectors on an ECM motor are:
A)
L1 and L2.
B)
T1 and T2.
C)
High speed and low speed.
D)
The power connector and control connector.
Answer:
D
Explanation:
A)
B)
C)
D)
158)
158)
The windings of a three-phase motor are:
A)
180° apart.
B)
90° apart.
C)
120° apart.
D)
360° apart.
Answer:
C
Explanation:
A)
B)
C)
D)
159)
159)
When measuring the resistance of relay coil it should be removed from the circuit and measure:
A)
.
B)
Some measurable resistance depending on the design of the relay.
C)
Infinite or OL on digital meters.
D)
None of the above.
Answer:
B
Explanation:
A)
B)
C)
D)
40
