Lakhasly

Course Outline

1. Introduction to AC Machinery
   Principles
   2- principle operations of (IM, IG)

د. محمد على – كليه الهندسة بأسوان - االت كهربية 2

Reference: Electrical Engineering

By
Theraja

Volume – II AC& DC Machines
3- principle operations of (SG, SM)

2

Syllabus

Induction Machine:
➢ Induction Motors:

-Principle of operation
-Constructional details
-Type of IM

➢Induction Generators:
-Principle of operation
Midterm Exam (third week in November)

Synchronous:
➢ Synchronous Generators:

-constructions
-operation Theory

• circle diagram


• parallel operation and synchronization

➢ Synchronous Motors:

-Principle of operation

3 د. محمد على – كليه الهندسة بأسوان - االت كهربية 2

د. محمد على – كليه الهندسة باسوان- االت كهربية 2

Mid term Exam on 14-11-2016 November

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المحاضره االولى

Induction Machine

5 د. محمد على – كليه الهندسة بأسوان - االت كهربية 2

د. محمد على – كليه الهندسة باسوان- االت كهربية 2

مقدمةتاريخية

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د. محمد على – كليه الهندسة باسوان- االت كهربية 2

التلميذ واالستاذ

اسلوب التجارب

تصادم أنماط المعيشة
تصادم التشابهات؟

حربالتيارات!

الرهان

الصدع وانطالقةتسال

تاريخ ما بعد هذه الحرب

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االت كهربية 2

كليه الهندسة باسوان-

. محمد على –
د

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االت كهربية 2

كليه الهندسة باسوان-

. محمد على –
د

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د. محمد على – كليه الهندسة بأسوان - االت كهربية 2
INDUCTION MOTOR

Classification of A.C. Motors
1- Regards As Their Principle Of Operation :

Asynchronous

induction

Squirrel cage Slip-ring

commutator

series shunt repulsion
Synchronous

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االت كهربية 2

كليه الهندسة بأسوان -

. محمد على –

11 د

د. محمد على – كليه الهندسة بأسوان - االت كهربية 2

In DC. motors, the electric power is
conducted directly to the armature (i.e.
rotating part) through brushes and
commutator
can be called a conduction motor.
DC. motor

in AC motors, the rotor does not
receive electric power by conduction
but by induction in exactly the same
way as the secondary of a 2-winding
transformer receives its power from the
primary

Induction

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د. محمد على – كليه الهندسة بأسوان - االت كهربية 2
Why Induction motor

?
Self
starting

It requires
minimum of
maintenance

It has very
simple and
extremely
rugged,

Its cost is
low and
it is very
reliable
It has
sufficiently
high
efficiency.

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د. محمد على – كليه الهندسة بأسوان - االت كهربية 2
Construction

a) stator
It is wound for a definite number of poles*,
the exact number of poles being determined
by the requirements of speed. Greater the
number of poles, lesser the speed and vice
versa.

*The number of poles P, produced in the rotating field is
P = 2n where n is the number of stator slots/pole/phase.
The magnetic flux rotating in synchronous
speed

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What is the effect of no. of poles on speed of motor?
Greater the number of poles, lesser is the speed of the motor and vice-versa. When 3-phase
supply is given to the stator winding, a rotating magnetic field of constant magnitude is
produced. This rotating field induces currents in the rotor by electromagnetic induction

p

f Ns

120


د. محمد على – كليه الهندسة بأسوان - االت كهربية 2

b) Rotor

i) Squirrel-cage rotor

(90%)
•The cage is constructed from
rotor bars (generally copper),
• The bars are then shorted
together with end rings at either
end
• There are no slip rings nor any

simplest and most rugged

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د. محمد على – كليه الهندسة بأسوان - االت كهربية 2
Slight Skew

1- it helps to make the motor run quietly by reducing the magnetic hum
2- Reducing Air Gap and Cogging
3- Increasing R, rugged
4- increase in the effective ratio
of transformation between
stator and rotor (K)
5- increased impedance of the
machine at a given slip
6- increased slip for a given
torque.

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د. محمد على – كليه الهندسة بأسوان - االت كهربية 2

ii) Wound rotor or slip-ring rotor
❖ This type of rotor is provided with 3-phase,
double-layer

❖ Self starting
❖ wound 3-phase even when the stator is wound
two-phase.

❖ under normal running conditions, the wound
rotor is short-circuited on itself just like the
squirrel-case rotor.
❖ These three brushes are further externally
connected to resistance

(starting torque)
(changing speed)

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د. محمد على – كليه الهندسة بأسوان - االت كهربية 2

Production of Rotating Field Production
Two-phase Supply
The principle of a 2-φ, 2-pole stator having
two identical windings, 90 space degrees
apart

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االت كهربية 2

كليه الهندسة بأسوان -

. محمد على –

19 د

د. محمد على – كليه الهندسة بأسوان - االت كهربية 2
Three-phase Supply

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االت كهربية 2

كليه الهندسة باسوان-

. محمد على –
د

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د. محمد على – كليه الهندسة بأسوان - االت كهربية 2

Why Does the Rotor Rotate ?

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