Dr. Suad Ibrahim Shahl
ELECTRICAL MACHINES II
Lecturer: Dr. Suad Ibrahim Shahl
Syllabus
I. II. III. IV. V. VI. VII. Introduction to AC Machine Synchronous Generators Synchronous Motors Three-Phase Induction Machines Three-Phase Induction Motors Induction Generators Induction Regulators
Recommended Textbook : 1) M.G.Say Alternating Current Machines Pitman Pub. 2) A.S. Langsdorf Theory of AC Machinery McGRAW-HILL Pub.
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Introduction to AC Machines
Dr. Suad Ibrahim Shahl
I.
Introduction to AC Machines
Classification of AC Rotating Machines
•Synchronous Machines:
•Synchronous Generators: A primary source of electrical energy. •Synchronous Motors: Used as motors as well as power factor compensators (synchronous condensers).
•Asynchronous (Induction) Machines:
•Induction Motors: Most widely used electrical motors in both domestic and industrial applications. •Induction Generators: Due to lack of a separate field excitation, these machines are rarely used as generators.
Energy Conversion
• Generators convert mechanical energy to electric energy. • Motors convert electric energy to mechanical energy. • The construction of motors and generators are similar. • Every generator can operate as a motor and vice versa. • The energy or power balance is : – Generator: Mechanical power = electric power + losses – Motor: Electric Power = Mechanical Power + losses.
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Introduction to AC Machines
Dr. Suad Ibrahim Shahl
AC winding design
The windings used in rotating electrical machines can be classified as Concentrated Windings • All the winding turns are wound together in series to form one multi-turn coil • All the turns have the same magnetic axis • Examples of concentrated winding are – field windings for salient-pole synchronous machines – D.C. machines – Primary and secondary windings of a transformer Distributed Windings • All the winding turns are arranged in several full-pitch or