Introduction to AC Motors
After the introduction of the DC electrical distribution system by Edison in the United States, a gradual transition to the more economical AC system commenced. Lighting worked as well on AC as on DC....
View ArticleSynchronous Motors
Single phase synchronous motors are available in small sizes for applications requiring precise timing such as time keeping, (clocks) and tape players. Though battery powered quartz regulated clocks...
View ArticleSynchronous Condenser
Synchronous motors load the power line with a leading power factor. This is often usefull in cancelling out the more commonly encountered lagging power factor caused by induction motors and other...
View ArticleReluctance Motor
The variable reluctance motor is based on the principle that an unrestrained piece of iron will move to complete a magnetic flux path with minimum reluctance, the magnetic analog of electrical...
View ArticleStepper Motors
A stepper motor is a "digital" version of the electric motor. The rotor moves in discrete steps as commanded, rather than rotating continuously like a conventional motor. When stopped but energized, a...
View ArticleBrushless DC Motor
Brushless DC motors were developed from conventional brushed DC motors with the availability of solid state power semiconductors. So, why do we discuss brushless DC motors in a chapter on AC motors?...
View ArticleTesla Polyphase Induction Motors
Most AC motors are induction motors. Induction motors are favored due to their ruggedness and simplicity. In fact, 90% of industrial motors are induction motors. Nikola Tesla conceived the basic...
View ArticleWound Rotor Induction Motors
A wound rotor induction motor has a stator like the squirrel cage induction motor, but a rotor with insulated windings brought out via slip rings and brushes. However, no power is applied to the slip...
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Single-Phase Induction Motors
A three phase motor may be run from a single phase power source. (Figure below) However, it will not self-start. It may be hand started in either direction, coming up to speed in a few seconds. It will...
View ArticleOther Specialized Motors
Shaded pole induction motor An easy way to provide starting torque to a single phase motor is to embed a shorted turn in each pole at 30o to 60o to the main winding. (Figure below) Typically 1/3 of...
View ArticleSelsyn (Synchro) Motors
Normally, the rotor windings of a wound rotor induction motor are shorted out after starting. During starting, resistance may be placed in series with the rotor windings to limit starting current. If...
View ArticleAC Commutator Motors
Charles Proteus Steinmetz's first job after arriving in America was to investigate problems encountered in the design of the alternating current version of the brushed commutator motor. The situation...
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