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Question
Why we use Carbon & graphite mixxed brushes in the DC motor?
 Question Submitted By :: Virendra Ku Mallah
I also faced this Question!!     Rank Answer Posted By  
 
  Re: Why we use Carbon & graphite mixxed brushes in the DC motor?
Answer
# 1
Grafite For Lubrication Carbon for current collection
purpose.
 
Is This Answer Correct ?    13 Yes 2 No
Virendra Ku Mallah
 
  Re: Why we use Carbon & graphite mixxed brushes in the DC motor?
Answer
# 2
THE PURPOSE OF CARBON BRUSHES ARE TO POLISHING THE SURFACE
OF THE COMMUTATOR AND TO REDUCE THE REACTENCE AT THE
COMMUTATOR.
 
Is This Answer Correct ?    6 Yes 3 No
Prasad
 
 
 
  Re: Why we use Carbon & graphite mixxed brushes in the DC motor?
Answer
# 3
carbon is hard material compared to graphiate so it will
give a stainsail strength of graphite at the time of full
load runing condition.and graphite use for the just collect
the current and passing.
 
Is This Answer Correct ?    4 Yes 4 No
Guest
 
  Re: Why we use Carbon & graphite mixxed brushes in the DC motor?
Answer
# 4
this wil reduce th sparking in the commutator 
Is This Answer Correct ?    4 Yes 5 No
Vinod Kumar T
 
  Re: Why we use Carbon & graphite mixxed brushes in the DC motor?
Answer
# 5
it has good peripheral speed and current density, self lubricating 
Is This Answer Correct ?    4 Yes 1 No
Karthik Raman.b
 
  Re: Why we use Carbon & graphite mixxed brushes in the DC motor?
Answer
# 6
According to the periodic table carbon lies in the list of
semiconductor having valency of 4 thus semiconductors have
the property that with increase in temp. their resistance
decreases. Thus when carbon brushes rub against the commutator
due to friction their temp. increases and resistance falls.
Thus they are used for collection of current in DC machines.
In AC systems slip rings are used.
 
Is This Answer Correct ?    8 Yes 0 No
Sahil Joseph
 

 
 
 
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