brush contacted with commutator collecting
ring as moving contacting substance.The
quality of the carbon brush directly influences
the appliance performance of the electrical
machine.The carbon brush we produce has
favorable electric conduction,heat conduction,lubrication
capability,and it has certain mechanical
intensity and small spark,low noise,long
life,use safely and reliably.The carbon
brush is an important part of the electrical
machine.This is due to the particular material
characteristics of carbon and graphite.
These include good frictional properties,
relatively good electrical and thermal conductivity
and high resistance to elevated temperatures.
does not melt, but sublimes at temperatures
above 3500 C degree. Thus, when switching
sparks and arcing occur, the formation of
beads of molten material, such as occur,
for example, on metalic contacts, is prevented.
of technological advances, the requirements,
which are imposed on carbon brushes, have
become vary extensive and diverse, In order
to achieve an optimum result in every application,
materials, sometimes with widely varying
properties, are available.
The excellent sliding properties of carbon
have been exploited for decades to transmit
power from overhead contact wires to electrically
driven traction units. In addition to these
sliding properties, carbon contact strips
possess high mechanical strength, good damping
properties, and are good conductors of heat
Normally, overhead contact wires are made
of copper which, upon contact with the carbon,
forms a carboniferous surface layer which
not only protects the contact wire but also
produces a low coefficient of friction in
the sliding contact. As a result, frictional
vibrations and the contact interruptions
associated with them are prevented, and
the radio interference common to metal contact
strip does not occur.
a result of the advantages made in the design
of electric traction units, greater demands
have been placed on the contact material.
The most important of these are:
High currents must be transmitted. Operation
in the critical load region is longer owing
to higher speeds, increased drive power
and the feedback of brake currents into
the overhead wire.
Reliable contacts must be assured over speed
range from 0 km/h to 400 km/h.
Contact wire and strip wear must be minimized
to reduce operating and maintenance cost.