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Carbon Brushes are Graphite ... right?

by Panthera Leo
Tags: brushes, carbon, graphite
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Panthera Leo
#1
Dec6-12, 06:09 AM
P: 110
I was wondering if the carbon brushes are graphite? and if yes how pure?
These days I am in Sri Lanka and can't find any seller offering pure graphite tubes, to be used as a heating element.

So I though what if.... I could use these carbon brushes instead as a cheap & fast alternative until I get one from abroad... lol

It's not a cleaver thought but any chance it could work???!!!

Thanks in advance
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sophiecentaur
#2
Dec8-12, 10:55 AM
Sci Advisor
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PF Gold
sophiecentaur's Avatar
P: 12,157
What resistance do you need? By design, brushes are short and fat and have as low a resistance as possible. A heating element needs to have high enough resistance to dissipate the power you require.- hence, long and thin (ish).
and7barton
#3
Dec8-12, 12:05 PM
P: 18
Brushes are not pure graphite, by a long way - They are a mixture of carbon, graphite and a collection of binders to "glue" them together. They are baked (sintered) during manufacture. When they are running inside a motor, some of those other chemicals are liberated and act as a lubricant between the brush and the commutator....... one of those lubricants, I believe, is plain old water.

sophiecentaur
#4
Dec8-12, 12:14 PM
Sci Advisor
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PF Gold
sophiecentaur's Avatar
P: 12,157
Carbon Brushes are Graphite ... right?

Did you think about getting carbon rods out of old D type cells?
http://www.youtube.com/watch?v=oN21ELKEIns
RocketSci5KN
#5
Dec10-12, 08:16 PM
P: 163
I wonder if a thick pencil core would work?
sophiecentaur
#6
Dec11-12, 03:21 AM
Sci Advisor
Thanks
PF Gold
sophiecentaur's Avatar
P: 12,157
Yes, in principle - I have done it. You need to specify how much power you want and what your operating voltage will be before you can expect a quantitative answer but you can definitely get a pencil lead too hot to touch!


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