Electric motors test 1 nameplates

Question 1

Since a nameplate has limited space to convey the ratings, most information is abbrieveated or coded to save space

Answer 1

T

Question 2

The actual voltage applied to a motor should be withing 15% of the motor’s nameplate rated voltage

Answer 2

F

Question 3

AC motors will typically use levels of 24V, 48V, 90V, or 180V

Answer 3

F

Question 4

The list of motor nameplate locked-rotor indicating code letters begins with the letter “A” and ends with “Z”

Answer 4

F

Question 5

Directly applying any frequency to a motor other than the nameplate rated frequency will change the motor;s operating characteristics and can damage the motor

Answer 5

T

Question 6

Electric motors typically require either direct current, single-phase AC or three phase AC

Answer 6

T

Question 7

When the nameplate of a motor does not list a service factor rating, a service factor rating of 1.00 is assumed and there is no built in safety margin for the motor

Answer 7

T

Question 8

Motor manufacturers produce only energy efficient motors

Answer 8

F

Question 9

Insulation breakdown is the most common cause of motor failure

Answer 9

T

Question 10

For fractional-HP frame sizes, the frame number represents the distance from the bottom of the base to the center of the shaft in 8ths of an inch.

Answer 10

F

Question 11

Typically operating environments for totally enclosed motor enclosures include the following: wet locations, dirty locations, oily locations, corrosive locations, extremely low and high temp locations gas and other hazardous locations and combustible dust locations

Answer 11

T

Question 12

Most motors include light-duty or medium-duty rated bearings

Answer 12

T

Question 13

The voltage applied to a motor must always exactly match the nameplate voltage rating

Answer 13

F

Question 14

For every 1% of voltage unbalance there can be up to a 6% current unbalance

Answer 14

T

Question 15

Design B motors are the most common type of industrial motors in use today.

Answer 15

T

Question 16

A __________ is a metal tag permanently attached to an electric motor frame that gives the required electrical ratings, operating ratings, and mechanical-design codes of the motor

Answer 16

nameplate

Question 17

Electrical ratings included on motor nameplates include a ____ rating and phase

Answer 17

current, voltage, frequench (alltheabove)

Question 18

The_________ rating is the amount of current a motor draws when delivering full rated power output.

Answer 18

current

Question 19

__________ current or starting current, or irush current is the amount of current a motor draws on startup

Answer 19

locked rotor current

Question 20

The _______ rating is a description of the expected or allowed application of a motor

Answer 20

usage

Question 21

The ________ is the difference between the winding temp of a running motor and the ambient temp

Answer 21

temp rise

Question 22

______ motors are used in applications such as compressors, waste-disposal systems, electric hoists, gate-opening motors, and other applications in which the motor need only be turned on for short time periods to meet application requirements

Answer 22

Intermittent-rated

Question 23

The NEMA_______ letter isa code letter representing a National Electric Manufacturers Association motor classification for the torque and current curves of a motor

Answer 23

design

Question 24

A design__________ motor is an integral-horsepower 3phase induction motor design made for full voltage starting nad high locked rotor torque, with locked rotor current not exceeding a specified value

Answer 24

B

Question 25

A_______ is a machine component used to reduce friction and maintain clearance between stationary and moving parts.

Answer 25

motor bearing

Question 26

The ____ is a code letter signifying the maximum operating temp of the insulation used in a motor

Answer 26

insulation class

Question 27

A design ________ motor is an integral-horsepower single phase motor design made for full voltage starting and locked rotor torque higher than for design M, N and O motors.

Answer 27

L

Question 28

The ________ , or duty cycle, is the amount of time a motor can be operated without being turned OFF to allow for cooling

Answer 28

operating time rating

Question 29

________ type is the type of protection given to a motor to shield the motor from the outside environment as well as to protect individuals form the electrical and rotating parts of the motor

Answer 29

Enclosuure

Question 30

A motor’s nameplate rating is the optimal voltage that should be connected to the
motor for best operating performance.

Answer 30

voltage

Question 31

__ ___ratings include the power rating, usage rating, service factor rating, speed
rating, operating time rating, motor efficiency rating, ambient temperature rating, and insulation
class.

Answer 31

operation

Question 32

The rating_______ is the amount of power a motor can deliver to a load

Answer 32

power

Question 33

The ____________rating of a motor is the approximate speed at which the rotor of a motor
rotates when delivering rated power to a load.

Answer 33

speed

Question 33

The __________is a number designating standard dimensions of a motor housing, shaft,
and mounting holes.

Answer 33

frame size

Question 34

____________motors have three- or four-digit frame numbers

Answer 34

integral-horsepower

Question 34

__________is a measure of the effectiveness with which a motor converts electrical
energy to mechanical energy.

Answer 34

motor-efficiency

Question 35

A design motor is a fractional-horsepower single-phase motor design made for fullvoltage starting and locked-rotor current not exceeding specified values.

Answer 35

N

Question 36

A(n) ___________motor enclosure is a motor enclosure that prevents air from entering
the motor

Answer 36

totally closed

Question 37

The____________ is a multiplier that represents the amount of load, beyond the rated
load, that can be placed on a motor without causing damage.

Answer 37

service factor

Question 38

Motors that are rated for ___________________ usage are used in a wide range of applications and
for mechanical loads such as conveyors, machine tools, and belt-driven equipment.

Answer 38

general purpose

Question 39

______________motor enclosures include general, drip-proof, splashproof, guarded,
semiguarded, and drip-proof fully guarded types.

Answer 39

open