Fractional Horse Power Motor Load

In this article the author outlines the broad and increasing use of fractional horse power motors and the chief causes for the advance in popularity of motor-driven machines. The success in this field of motor application has been largely due to the perfection of a reliable and simple single-phase motor. The development in the design and construction of the single-phase motor is traced from its origination to the present time, and the operating characteristics of the commoner types of single-phase motors are described and illustrated by the use of speed-torque curves. The correct application of small motors is of utmost importance and requires a careful analysis of motor characteristics, the characteristics of the driven machine and of the supply circuit, with the limitations of each. The author deals particularly with the characteristics of the split-phase induction motor, which is used so extensively, and points out the functions of the centrifugal clutch when employed as a component part of this motor. A reference diagram is presented which is of service in applying small motors.