شرح الآلات الحثية

**thegladiator**

سوف نقوم بإذن الله شرح الآلات الحثيه
وسوف يكون بإذن الله شرح مبسط مع الإيضاحات الازمه إن شاء الله
بيقدم ورده

والآن بسم الله نبدأ

**YeHi@$MmZ**

منور يا عمر
ومنتظرين الشرح
ونتمنى تفاعل الأعضاء مع الموضوع
وينورنا باشمهندسين قسم باوران شاء الله

**الحبار**

جزاك الله خيرا يا بشمهندس لفتحك للموضوع والمبادره الفعاله وننتظر منك كل جديد وأرجو من الأخوه المهندسين التفاعل وسيتم إرسال تنبيه بكل شرح جديد على إيميلات الأعضاء
والله الموفق.

**thegladiator**

Induction machine

Introduction

Induction machine gain its name because energy transfer by induction not conducion

Induction machine invented by tesla

It is very widely used as motor and little used as agenerator

Advantage of induction machine

1_small in size

2_rugged

3_cheap

4_require little maintenance

Construction of induction machine

1_STATOR
it is simple consist of three phase winding placed in aslots

This slots is skewed to

1_reduce magnitec hum

2_reduce motor locking tendency

2_ROTOR

Induction machine may classified with respect to its rotor into two categories

1_wound rotor

The rotor is simply consist of athree phase winding exactly like stator

2_squiral cage motor

In this type rotor consist of solid bars shorted at both ends

Theory of operation

Three phase supply applied to the stator so amagnetic flux produced in the air gab

Between stator and rotor and by faraday’s law

Emf induced in the rotor this EMF circulate current in the rotor as aresult

Of this current flux produced

Due to interaction between stator’sflux and rotor’s flux atorque produced

Cause rotor to rotate in the same direction of synchronous speed.

Rotor speed must be less than synchronous speed whn operate as amotor…………………………..ehy????
because

If rotor rotate at the same speed of synchronous speed

1_novoltage induced

2_no current flow

3_torque induced equal to zero

Starting of inuction machine

Induction machine draw avery large current at starting (5-8 times like full load current)

So to reduce this current we may use the following method

1_in case of wound rotor we may connect resistance series with rotor

At starting and then short circuit this resistance at full load.

2_using autotransformer between line and the motor to

Reduce line voltage at starting and then at full load

Full line voltage applied to the machine

Speed control of induction machine

Speed control of induction machine is very difficult

But we may could control it dy

1_PAM: pole amplitude modulation

2_consequent pole

3_changing frequency

Inter view questions and its answers:

1_what do you mean by synchoronous speed?

The speed at which the flux produced by 3-PHASe stator winding

2_why is the field producing winding of a 3_PHASE induction machine made stationary?
making the field winding stationary element eliminates the use of slip rings and brushes and ,there for,will result in avery trouble free construction

3_why does the rotor of a 3-phase induction motor rotate in the same direction as the rotating field??
this can be explained by lenz’s law the direction of rotor current will be such so as to oppose the cause producing them.now the cause producing the rotor

Current is relative speed etween the rotating field and stationary rotor .hence to reduce this relative speed the rotor starts running in the same direction as the stator field and tries to catch it.

4_the air gab between the rotor and stator is made as smallas possible ??
in order that

1_mutual flux may be produced with aminimum exciting current

2_leakage reactance are as small as possible

5_why is the power factor low at no load ??

Because of the air gab ,the reluctance of the magnetic circuit is very high.

6_what are the advantage of skewed slots in the rotor??

Because this arrangement offer the following advantage

1_it reduce motor noise and variation

2_it increase the starting torque and reduce the starting current

**YeHi@$MmZ**

مجهود جميل منك يا باشمهندس عمر

بارك الله فيك
وقد تم التثبيت لهذا الموضوع الرائع

**thegladiator**

YeHi@$MmZ كتب:

منور يا عمر
ومنتظرين الشرح
ونتمنى تفاعل الأعضاء مع الموضوع
وينورنا باشمهندسين قسم باوران شاء الله

**thegladiator**

YeHi@$MmZ كتب:

مجهود جميل منك يا باشمهندس عمر

بارك الله فيك
وقد تم التثبيت لهذا الموضوع الرائع

محمد_العزاوي

بارك الله بالجهود

احمد منصور

بارك الله فيك يا بشمهندس بس انا عايز معادلات و دائرة و مسائل الinduction machine