# ACHR131 Module Final Review

50 Questions

Possible Multiple Choice Questions

Questions and Answers
• 1.
A split-phase has a _____ winding and a _____winding.
• A.

Start, run

• B.

Start, common

• C.

Common, run

• D.

Run, common

• 2.
A split-phase motor can use a _____to energize and de-energize the start winding.
• A.

Potential relay

• B.

Current relay

• C.

Centrifugal switch

• D.

All of the above

• 3.
A current magnetic relay opens and closes its contacts based on the _____.
• A.

Current in the start winding

• B.

Voltage across the start winding

• C.

Voltage across the run winding

• D.

Current in the run winding

• 4.
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

• 5.
A split-phase motor that has a current relay and a start capacitor is called a _____motor.
• A.

Capacitor Start, Capacitor Run (CSCR)

• B.

Capacitor Start, Induction Run (CSIR)

• C.

Induction Start, Induction Run (ISIR)

• D.

Permanent Split Capacitor (PSC)

• 6.
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.)
• A.

5 microfarads

• B.

4 microfarads

• C.

20 microfarads

• D.

25 microfarads

• 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.)
• A.

4 microfarads

• B.

5 microfarads

• C.

20 microfarads

• D.

25 microfarads

• 8.
The starting device usually used on single phase, fractional horsepower compressor motors is the _____.
• A.

Potential relay

• B.

Current relay

• C.

Centrifugal switch

• D.

None of the above

• 9.
A motor's speed is determined by _____.
• A.

Size

• B.

Voltage

• C.

Amperage

• D.

Number of motor poles

• 10.
Start windings are placed _____the run windings.
• A.

Outside

• B.

Inside

• C.

Between

• D.

In series with

• 11.
The start windings have _____.
• A.

Fewer turns than the run windings

• B.

More turns than the run windings

• C.

The same number of turns as the run windings

• D.

Larger diameter wire than the run windings

• 12.
When a general duty split-phase motor reaches approximately 75% of its operating speed, the start winding is de-energized by a _____.
• A.

Circuit board

• B.

Capacitor

• C.

Centrifugal switch

• D.

Dual voltage switch

• 13.
Capacitors wired in series with the starting winding provide _____.
• A.

Longer starting time

• B.

Greater starting torque

• C.

An aid in starting three phase motors

• D.

More efficient operation at full load speed

• 14.
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

• 15.
Three phase motors have _____.
• A.

Three start and three run windings for each phase

• B.

One start and one run winding for each phase

• C.

Run windings only

• D.

A start switch in each phase circuit

• 16.
The positive-temperature-coefficient start device is a type of _____.
• A.

Capacitor

• B.

Thermistor

• C.

Switching device

• D.

Diode

• 17.
A permanent split-capacitor motor has a _____.
• A.

Start and run capacitor

• B.

Start capacitor only

• C.

Run capacitor only

• D.

Split phase capacitor

• 18.
When referring to motors, to what does the "insulation class" relate?
• A.

The noise level of the motor

• B.

The type of base on which the motor is mounted

• C.

The normal operating temperature of the motor

• D.

Both a and b

• 19.
Why are explosion-proof motors not normally used on standard equipment?
• A.

They are too large.

• B.

They are too noisy.

• C.

They are too expensive.

• D.

They cannot be replaced.

• 20.
The motor that should be used in a potentially wet area is a(n) _____motor.
• A.

Enclosed

• B.

Drip proof

• C.

Explosion proof

• D.

Open

• 21.
Which of the following voltages are not safe for a 208-V motor to operate?
• A.

170 volts

• B.

220 volts

• C.

238 volts

• D.

Both a and c

• 22.
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

• 23.
If the voltage supplied to the motor is well below the motor rated voltage, the current draw will be _____it should be.
• A.

Lower than

• B.

The same as

• C.

Higher than

• D.

In reverse polarity than

• 24.
The voltage tolerance of a standard electric motor is _____.
• A.

+10% -5%

• B.

+5% -10%

• C.

+10% -10%

• D.

+15% -15%

• 25.
The locked-rotor amperage is normally _____times as great as the run-load amperage.
• A.

Two

• B.

Three

• C.

Five

• D.

Ten

• 26.
A direct-drive motor is usually connected to a load with a _____.
• A.

Cradle mount

• B.

Rigid base mount

• C.

Pulley

• D.

Coupling

• 27.
The width of a drive belt is classified as _____.
• A.

Large or small

• B.

Narrow or wide

• C.

A or B

• D.

1 or 2

• 28.
An instrument often used to check the alignment of two shafts is the _____.
• A.

Micronometer

• B.

Dial indicator

• C.

Monometer

• D.

Sling psychrometer

• 29.
A slotted screw at the bottom of the bearing housing is called a _____.
• A.

Drain plug

• B.

Purge screw

• C.

Relief plug

• D.

Retaining screw

• 30.
Grounding straps are required on resilient mounted motors to _____.
• A.

Prevent rotation of the motor in the mount

• B.

Help reduce motor vibration transfer to the object on which the motor is mounted

• C.

Ground the motor in case of winding failure

• D.

Act as the position for locating the motor leads

• 31.
When a contractor'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

• 32.
Technician "A" says that if you take a voltage reading from terminal "L1" to terminal "T1" on a contactor whose coil is energized, you should read zero volts.  Technician "B" says that contactors can only have normally open contacts.  Which of the following statements is correct?
• A.

Technician "A" is correct. Technician "B" is correct.

• B.

Technician "A" is correct. Technician "B" is incorrect.

• C.

Technician "A" is incorrect. Technician "B" is correct.

• D.

Technician "A" is incorrect. Technician "B" is incorrect.

• 33.
An inherent motor protector is a _____ .
• A.

Circuit breaker

• B.

Motor starter overload

• C.

Thermally activated device in the motor winding

• D.

Line fuse

• 34.
The service factor of an electric motor is determined by _____.
• A.

National Electrical Code

• B.

National Electrical Manufacturers Association code

• C.

Motor's reserve capacity

• D.

The required wire size supplying power to the motor

• 35.
Which of the following overload devices is not affected by ambient temperature?
• A.

Solder pot

• B.

Magnetic

• C.

Bimetal

• D.

Time-delay fuse

• 36.
Standards for motor overload protection are set by the _____.
• A.

United States Department of Transportation

• B.

National Electrical Code

• C.

Environmental Protection Agency

• D.

American National Standards Institute

• 37.
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.

Reduce the cost of the contactor

• B.

Make it easier to wire the unit

• C.

Teach the service technician not to put hands in the unit with the power on

• D.

Provide off-cycle heat to the compressor

• 38.
Beside maintaining pressure on the contacts for current carrying capacity, the pressure springs have a second important function.  This is to _____.
• A.

Keep the contacts in line

• B.

Help obtain equal contacts against the stationary contacts

• C.

Slow down the pull of the armature into place to reduce the noise

• D.

Increase the power required to close the contacts

• 39.
What is the best method to repair a fractional horsepower motor that has bad bearings?
• A.

Replace the bearings.

• B.

Replace the bearings and shaft.

• C.

Add a capacitor to the circuit for added torque.

• D.

Replace the entire motor.

• 40.
A technician needs to check a single-phase compressor. He labels the three terminals "A," "B," and "C" and take 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.

A: common B: start C: run

• B.

Cannot identify terminals: winding grounded

• C.

A: start B: run C: common

• D.

Cannot identify terminals: open winding

• 41.
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?
• A.

Technician "A" is correct. Technician "B" is correct.

• B.

Technician "A" is correct. Technician "B" is incorrect.

• C.

Technician "A" is incorrect. Technician "B" is correct.

• D.

Technician "A" is incorrect. Technician "B" is incorrect.

• 42.
• A.

Technician "A" is correct. Technician "B" is correct.

• B.

Technician "A" is correct. Technician "B" is incorrect.

• C.

Technician "A" is incorrect. Technician "B" is correct.

• D.

Technician "A" is incorrect. Technician "B" is incorrect.

• 43.
If a motor hums but does not start, there is a potential problem _____ .
• A.

With the starting components

• B.

With an open winding

• C.

With insufficient supply voltage

• D.

All of the above

• 44.
An open winding in an electric motor means that _____ .
• A.

The winding is making contact with the motor failure

• B.

One winding is making contact with another winding

• C.

A wire in a winding is broken

• D.

The centrifugal switch to the start winding is open

• 45.
If the resistance of the run winding decreases, the _____ .
• A.

Motor probably will not start

• B.

Motor will draw too much current while it is running

• C.

Centrifugal starting switch will not start the motor

• D.

Load on the motor is probably too great

• 46.
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.

Has no effect on the electrical connection

• B.

Acts as an electrical resistance and causes the connection to heat more

• C.

Decrease the resistance

• D.

None of the above

• 47.
A megger _____ .
• A.

Is a ammeter that can measure small amounts of current

• B.

Is digital voltmeter that measures very high resistances

• C.

Measures high voltage direct current

• D.

Measures very high resistances

• 48.
The recommended way to discharge a capacitor is to _____ .
• A.

Place a screwdriver across the terminals

• B.

Assume it will discharge itself over a period of time

• C.

Use 20,000 ohm 5 watt resistor that has had insulated leads soldered to it

• D.

Use an ohmmeter

• 49.
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

• 50.
Most electrical problems with an electric motor are _____ .
• A.

Short circuited windings, closed windings, and grounded windings

• B.

Short circuited windings, open windings, and grounded windings

• C.

All of the above

• D.

None of the above

Related Quizzes
Featured Quizzes
Related Topics