Answer / nagendra murthy

any DC motor or generator will need to have a commutator. A
commutator is a device used to change the direction of
current flow through the motor. The reason a cummutator is
needed is because a DC current in a magnetic field can only
turn the motor through 180 degrees, after which the force
will cause the motor to return to a fixed position. In order
to make the force turn the motor the current needs to be
changed every 180 degrees so that the force will act in the
opposite direction, spinning the motor around. This is
achieved using a commutator. The commutator is normally a
device which brushes against terminals in the motor. As the
motor turns the terminals in contact with the brushes
change, and so does the current.

Answer / paragbajpai

1.carbon brushes are used as it is having high resistance so
that time constant will be reduced that means commutation
will be improved.
2. it has self relieving property

Answer / k.prakashchandra

1.A good conductor 2.has desired hardness 3 can be easily
Reshaped 4.cheap 5. easily available 5. does not corrode 6.
cleaning is easy 7.weather resistant 8 not inflammable etc

Answer / sarath k

the carbon brushes are used as commutators because of resistance commutation and the carbon has self polishing property

Answer / satheeshkumar

Only The carbon having possessing the negative temperature coefficient This is the main reason using for commutation porpose (The ratio of increasing resistance per degree centigrade o the resistance at 0 degree centigrade) dippend the carbon inverse action must take place

Answer / gautam

carbon acha nahin hota hai

What are the various types of BUSBAR Schemes? explain each

1 Answers   NTPC,

Is there any difference between load based power plant and coal based power plant?

1 Answers  

Can VFD step up to 60 Hz if it is designed to receive 50 Hz input?

3 Answers  

how to find out capacitor range?

2 Answers  

what is LT & HT?

6 Answers  

Why power factor does not occur in DG set ?

6 Answers  

explain why the secondary terminal of current transformer should not be lift open circuited.

2 Answers  

What is order of the system?

0 Answers  

why voltage rating not mention at HPSV or HPMV lamps?

2 Answers   OPS,

What is GD2(kg-m2) for Sq. cage ind. motor?

2 Answers   ABC, Essar, MMM,

Where the ON LOAD TAP CHANGER is provided in the setp up transformer?

2 Answers  

what is current overloading in stack

0 Answers