unit 20 multiple choice

50hp

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?

60

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

synchronous speed

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

9

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

TENV

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

1

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.

iron

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.

746 watts or 33,000 ft-lb/min

The formula for horsepower is 1 hp = ____.

c

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,B,F,H

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.