Deck 20: Motor Nameplate Data

Question 1

Assume that a motor produces an output torque of 152.23 foot pounds at a speed of 1725 RPM. What is the horsepower output of the motor?

A) Hp = 0.36
B) Hp = 50
C) Hp = 463.49
D) Hp = 595.13

Answer 1

B

Question 2

Most dual voltage motors contain ____ leads in the terminal connection box.

A) 4
B) 7
C) 9
D) 12

Answer 2

C

Question 3

Full load motor speed is determined by several factors. The main factor is the ____.

A) number of stator poles per phase
B) frequency of the applied voltage
C) type of squirrel cage winding
D) synchronous speed

Answer 3

D

Question 4

Three-phase motors can be divided into three general types, squirrel cage induction, wound rotor induction, and synchronous.

Question 5

An example of an intermittent duty motor is the starter motor on an automobile. These motors develop a small amount of horsepower in a small case size.

Question 6

Horsepower can be rated in watts, where 1 hp = 346 watts.

Question 7

The letter ____ designates a flange mounted motor. This is the most popular style for flange mounted motors, which have a specific bolt pattern on the shaft end of the motor that permits mounting to the driven device.

A) C
B) D
C) H
D) JP

Question 8

When registering a motor for manufacturer's warranty, it is generally necessary to list the serial number.

Question 9

The formula for horsepower is 1 hp = ____.

A) 330 ft-lb/min
B) 3,300 lb-ft/min
C) 33,000 lb-ft/min
D) 33,000 ft-lb/min

Question 10

Such factors as the amount of ____ used in the stator, the wire size, the number of turns of wire, and the rotor design all play a part in the operating characteristics of a motor.

A) copper
B) lead
C) steel
D) iron

Question 11

Selecting motors with a service factor greater than ____ allows for cooler winding temperatures at rated load, protects against intermittent heat rises, and helps to offset low or unbalanced line voltages.

A) 1
B) 10
C) 100
D) 1,000

Question 12

Frequency is measured in Hertz. The standard frequency used throughout the United States and Canada is ____ Hz.

A) 40
B) 50
C) 60
D) 100

Question 13

The locked rotor code letter is determined by the construction of the squirrel cage rotor. It can be used to determine the approximate amount of inrush current when the motor is started.

Question 14

When dealing with frame sizes, a general rule of thumb is that the centerline shaft height above the bottom of the base is the first two digits of the frame number divided by 3.

Question 15

Motors have different types of enclosures depending on the application. ____ indicates motors that are generally used in harsh environments such as chemical plants.

A) EXP
B) ODP
C) TEFC
D) TENV

Question 16

The efficiency of a motor basically describes the amount of kinetic energy supplied to the motor that is converted into electrical energy.

Question 17

Most industrial motors are 3-phase, which means that the power connected to them is three separate lines with the voltages 120 degrees out-of-phase with each other.

Question 18

Motors have a rated horsepower that is determined by the amount of torque they can produce at a certain speed.

Question 19

D motors have low starting torque and high starting current.

Question 20

The thermal capacity of different insulations is rated as ____. The letters indicate the amount of temperature each is designed to handle over a 20,000 hour period operating at full load.

A) A, B, C, and D
B) A, B, F, and H
C) B, D, F, and H
D) F, H, J and P