Question 1

How can a technician determine if a run capacitor has overheated?

Accepted Answer

A run capacitor is contained i

Question 2

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 ____________________.

Accepted Answer

The answer of If the needle of an ohmmeter used...

Question 3

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

Accepted Answer

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. 
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.

Question 4

When the leads of an ohmmeter are placed on the terminals of a capacitor, what should the needle of the ohmmeter do?

Accepted Answer

Start toward the zer

Question 5

If a resilient-mounted motor develops a short to the frame, the technician can simply cut the ground strap wire as a permanent repair.

Accepted Answer

A) True 
 B)False

Question 6

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 ____.

Accepted Answer

A)  has no effect on the electrical connection 
B)  acts as an electrical resistance and causes the connection to heat more 
C)  decreases the resistance 
D)  none of the above 
A)  has no effect on the electrical connection 
B)  acts as an electrical resistance and causes the connection to heat more 
C)  decreases the resistance 
D)  none of the above

Question 7

The electrical components for a fully welded hermetic compressor are checked at the disconnect box for the compressor unit.

Accepted Answer

A) True 
 B)False

Question 8

If a motor hums but does not start, there is a potential problem ____.

Accepted Answer

A)  with the starting components 
B)  with an open winding 
C)  with insufficient supply voltage 
D)  all of the above 
A)  with the starting components 
B)  with an open winding 
C)  with insufficient supply voltage 
D)  all of the above

Question 9

A megger ____.

Accepted Answer

A)  is an ammeter that can measure very small amounts of current 
B)  is a digital voltmeter that measures very high resistances 
C)  measures high voltage direct current 
D)  measures very high resistances 
A)  is an ammeter that can measure very small amounts of current 
B)  is a digital voltmeter that measures very high resistances 
C)  measures high voltage direct current 
D)  measures very high resistances

Question 10

Most electrical problems with an electric motor are ____.

Accepted Answer

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 
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

Exam 20: Troubleshooting Electric Motors

How can a technician determine if a run capacitor has overheated?

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 ____________________.

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

When the leads of an ohmmeter are placed on the terminals of a capacitor, what should the needle of the ohmmeter do?

If a resilient-mounted motor develops a short to the frame, the technician can simply cut the ground strap wire as a permanent repair.

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 ____.

The electrical components for a fully welded hermetic compressor are checked at the disconnect box for the compressor unit.

If a motor hums but does not start, there is a potential problem ____.

A megger ____.

Most electrical problems with an electric motor are ____.

Heat and Pressure

Matter and Energy

Refrigeration and Refrigerants

General Safety Practices

Tools and Equipment

Fasteners

Tubing and Piping

Leak Detection, System Evacuation and System Clean-Up

Refrigerant and Oil Chemistry and Managementrecovery, Recycling, Reclaiming, and Retrofitting

System Charging

Calibrating Instruments

Basic Electricity and Magnetism

Introduction to Automatic Controls

Automatic Control Components and Applications

Troubleshooting Basic Controls

Advanced Automatic Controlsdirect Digital Controls Ddc and Pneumatics

Types of Electric Motors

Application of Motors

Motor Controls

Evaporators and the Refrigeration System

Condensers

Compressors

Expansion Devices

Special Refrigeration System Components

Application of Refrigeration Systems

Commercial Ice Machines

Special Refrigeration Applications

Troubleshooting and Typical Operating Conditions for Commercial Refrigeration

Electric Heat

Gas Heat

Oil Heat

Hydronic Heat

Indoor Air Quality

Comfort and Psychrometrics

Refrigeration Applied to Air Conditioning

Air Distribution and Balance

Installation

Residential Energy Auditing

Typical Operating Conditions

Troubleshooting

Heat Gain and Heat Loss in Buildings

Air Source Heat Pumps

Geothermal Heat Pumps

Domestic Refrigerators and Freezers

Room Air Conditioners

High-Pressure, Low-Pressure, and Absorption Chilled-Water Systems

Cooling Towers and Pumps

Operation, Maintenance, and Troubleshooting of Chilled-Water Air Conditioning Systems

Commercial Rooftop, Packaged, Variable Refrigerant Flow, and Variable Air Volume Systems

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