DYNMO AND ALTERNATOR

 DYNMO AND ALTERNATOR

    it convert chmical energy into electrical energy. therer are mainly two type of generators
i) DC generator                ii) AC generator

i) Dynmo ( DC generator) :-

      which covert mechanical energy from engine sahft into direct current .  conductor were loop is related in a magnetic field to induce electric current into DC with the help of a computator . its function is to generate direct current electricity for charging the battery and fuction of other electrical system in the automobile
# various types of dynmo :-
      - Field system :-
              electro magnets are used which form uniform magnetic field . there are following four parts of fluid system

a) Yoke/frame :-

      outer cylindrical frame of m/c is called yobe. it will provide mech. protection to inner parts . it also provide low reluctants path to magnetic     yobe of small m/c is  made up of cast iron of cast steel. yobe is also called magnetic frame of m/c

b) pole Core and pole shoe :-

      pole core and shoe is fixed to magnetic frame by bolts. pole core is used to carry winding. even number of pole are are used . curve surface of pole is made up of shoe. pole core is made up of lamination of thin sheets of steel to reduce any current loss

d) Field Coils :-

     each pole core has one or moe copper wires placed over it. these will produce magnetic field . field coils are also called exciting coils. these field coils are connected in series . these coils are connected in such a way that when current pass from field coils for attain opposite polarity

2. Armature :-

     rotating part of DC m/c is called armature . there are two parts
- armature core
- armature winding
    armature is made up of shaft. upon the shaft laminated cylinder is placed this cylinder is called armature core
    armature core is made up of silicon steel stamping . each stamping is 0.3mm to 0.5mm
    slots in outer side of armature core carry conductor. these conductor are called armature winding

3. Commutator :-

      it is a rotating switch placed between armature and external circuit . it perform following function:-
- it convert alternating current into undirectional current
- it convert alternating torque into undirectional torque

4. Brushes and brush holder ;-

       current is collected v from armature by using two or more carbon brushes. brushes are placed over commutator
     these are link between armature winding and external circuit , armature of DC m/c is connected to external load by commutator abd brushes . brushes are held in particular position by brush holder

# Cut out relay :-

    - Relay :-

        it regulate the flow of charging current to the battery

  - Cutout relay :-

       it is also called circuit breaker . when the generator is producing sufficient current to charge the battery . cutout relay keeps the circuit close
   but when the generator speed is very low it does not produce the requirement amount of current to charge the battery

# Construction :-

         a simple sketch of cut out basically the cut out relay is a magnetic switch . it consist of two winding
- series                - shunt
these winding are assembled on an iron ore. a flat steel armature is mounted above the core. one end of shunt winding is connected to armature and the other end is earth

 #Working :-

          when the generator is producing sufficient amount of current a magnetic field is created in the core due to winding. this magnetic field attract the armature contact points are close and the battery starts charging . when the generator speed is lowered. the  output voltage is also lowered . so, the current starts to flow from battery to generator hence, the direction of flow of current is reversed in series winding in cpmparision to shunt winding . hence the strength of magnetic field reduces. so, the circuit breaks and the battery is cut from the generator

# adjustment of cutout :-

     the main adjustment factor is adjusting the gap between armature and contact points. when the cutout is not working . different types of arrangement are providing for the adjustment of different automobiles . one the arrangement consist of a spring post with the help of a bolt the tension os the spring can be increase or decrease

@ charging of battery from alternator :-

      to convert AC into DC . these are 6 silicon diode which make rectifier . diode is an electronic device that permits current flow  through it in one direction only
           the current output from each stator winding is connected of two diode one being present diode and other being negative diode and pure DC current is available at output . this current can be used for charging battery and operating other accesories

@ Regulator :-

     it control the amount of electricity to be supplied . the function of the regulators is to control the generator output to receive maximum value

# Construction :-

        combine voltage and current regulator is most commonly used. it consist of a shunt winding and series winding besides a cut out relay.

#Voltage Regulator :-

      it consist of core around which a shunt winding and a series winding are provided is connected to the field terminal of the regulator at one end and towards at the other end to earth
the purpose of the voltage regulator is to leaving the output voltage to a sale value and prevent it from exceeding this value. the regulator is already set for this maximum value of volatge when the generator produce high voltage then the limit, the magnetic force created by shunt and series winding  will pull the armature down words, thus breaking the contact points. at this time a resistance will be inserted in the generator filled circuit due to this resistance the voltage will draw by this way the volatage is  control

# Current regulator :-

          the current regulator construct with a series winding around a core one end of the windng and the other end to the generator terminal
 the purpose of the current regulators is to control the maximum output of the generator and preventing it from exceeding a predetermined value . when the generator output reaches the maximum output