WHICH MATERIALS USED IN MACHINE PARTS ????

-

WHICH MATERIALS USED IN MACHINE PARTS  ????


Question :

What are the materials used for the following parts of a dc machine,explain their functions.
1)Rotor core 
2)Commutator bars
3)Yoke
4)Brushes
5)Pole shoes

Answers :-

1)ROTOR CORE


Rotor core is made from high permeability silicon steel stampings .It's function is to provide a path of very low reluctance to the magnetic flux.

2) COMMUTATOR BARS


Commutator bars are built up of hard drawn copper or drop forged copper. The main function of Commutator are :
     
        (a)It provides the electrical connections between the rotating armature coils and the stationary external circuit.
    
        (b)As the armature rotates ,it performs a switching action reversing the electrical connections between the external circuit and each armature coil in turn so that the armature coil voltages add together and result in a dc output voltage.
     
        (c)It also keeps the rotor or armature mmf stationary in space .

3)YOKE


Yoke is made of cast iron in case of small machines but fabricated steel in case of large machines.It acts as a frame of the machine and carries the magnetic flux produced by poles

4)BRUSHES


Brushes are made of carbon ,carbon graphite, metal graphite or copper.The function of brushes is to collect current from the Commutator and supply it to the external load circuit.

5)POLE SHOES 


Pole shoes are made of thin sheets of steel.The pole shoe acts as a support to the field coils and spreads out the flux over the armature periphery more uniformly and also being of larger cross section reduces the reluctance of the magnetic path .


              👍👍  ALL  THE  BEST  👍👍

                             Please share 

Comments

Post a Comment

Popular posts from this blog

Basic Electrical - III

-
1. An electric current is the (A) flow of electrons. (B) opposition to electrons. (C) storage of charge. (D) ionization of atom. 2. Electric pressure is also called (A) resistance. (B) power. (C) voltage. (D) energy. 3. Which of the following is best conductor of electricity? (A) aluminum. (B) silver. (C) copper. (D) gold. 4. The dielectric material used in variable capacitor is generally (A) mica. (B) air. (C) ceramic. (D) electrolyte.  5. What does a capacitor store? (A) Current. (B) Charge. (C) Voltage. (D) Power.                                      Comment Your Answers                             👍Share it to your friends👍                
Read more

Line Resistance in Transmission Line

-
Image
Line Resistance in Transmission Line  :- 👉Every electric conductor oppose the flow of current in it ,this is known as resistance. 👉The power loss (I^2R) in the transmission line occurs due to this resistance. 👉The ohmic resistance R of a conductor of length ' l ' and uniform cross sectional area 'a',                                  R= ρl/a  Where, R=Total resistance in Transmission Line, ρ=Resistivity or specific resistance of conductor material , l=Length of the conductor, a= Area of cross section, 👉The Resistivity or specific resistance of the conductor is depends not only on the conductor material but also it's temperature. 👉For example ,if ρ₁ and ρ₂ are the values of resistivity at different temperatures t₁ and t₂ ,then ρ₂=ρ₁{1+α(t₂-t₁)} Where, a = Temparature coefficient of resistance of the material. 👉The value of the temparature coefficient of resistance i...
Read more

Difference between Node and Junction

-
Image
Difference between Node and Junction :-   1)NODE:-    A point at which two or more elements are joints together is called node.    2)JUNCTION:-      While a point   where three or more        branches  meet   together  is  called   a junction.                   In the below figure we can say that points  a,b,c,d,e  and  f  are  nodes     and point  c &  f  are  called   junction.  While point c & f itself a node. Nodes -> a,b,c,d,e,f Junctions ->c,f  By observing above node and junction we can say that,  every junction becomes a node but every node not becomes a junction. ● SHARE IT
Read more