AC Motors, Single and Three Phase

About AC Motors, Single and Three Phase

In this course students will learn the operation, construction, and wiring of single phase motors. It will begin with a review of single phase AC generation and how it directly applies to the operation of single phase AC motors. With graphics and demonstrations, we will the look into the construction of an AC motor and discuss the interactions of magnetic fields created by the AC action. You will learn why a single phase motor is not self-starting, and the methods and materials used to start this motor such as the split-phase and the centrifugal switch. We will then wire the single phase motor for dual voltage operation; 120 and 208 volts respectively. After this, the students will be able to see how a single phase motor is reversed. We will discuss the purpose of adding a capacitor for the starting operation of a single phase motor. Next, we will look at the construction, operation, and wiring of a three phase dual voltage motor for dual voltage operating. There will be a review of three phase generation and how it aids in the starting and running of the motor. You'll see how a three phase motor is wired for low and high voltage operation, and how the three phase motor is reversed. You'll learn about the nameplate data that is required by NEMA to include voltage, amperage, HP rating, number of phases, ambient temperature ratings, frame size, code letters that represent the start up inrush current allowed for the motor, and the service factor (SF) which lets you know what percentage above rated wattages the motor can safely operate.