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Semimanufactured electrographite,
having EGR symbol, is a material for collecting
brushes with medim alling voltage, at the brush-collector contact exist a low
or medium
friction coefficient so that are running with low losses. Electrographite
brushes equip all
modern stationery or of speed traction machines, having low, medium or high
voltage,
in constant or variable electric current. Electrographite materials are manufactured
in
various qualities like EGR-3,
EGR-4, EGR-5, EGR-8, EGR-9, EGR-10, EGR-12, EGR-14,
EGR-16, EGR-18,
EGR-19, EGR-20, and EGR-23.
Electrographite
brushes are generally use
for c.c. stationary from industrial equipments,
technological machines by siderurgical industry, textiles, paper and celulose
coutchouk
manufacturing, servomotors with axial interfer and for cilindrical rotors,
at electric universal
motors. In domain of the electrical traction, electrographite brushes are used
to equip
electrical auxiliary machines from electrical diesel locomotive and for vous
railwai and
to equip motors of urban traction (trans and buses).
Table
with parameters of running recommanded for
electrographite materials in normal conditions of
running
|
Group
of
semimanufactured
|
Mark
|
Density
of curent
|
Peripheral
speed max.
|
Pressure
on brush
|
|
|
A/cm²
|
m/s
|
kN/m²
|
|
0
|
1
|
2
|
3
|
4
|
|
ELECTROGRAPHITE
|
EGR
- 3
|
10
|
50
|
20
- 22
|
|
EGR - 4
|
12
|
55
|
20
- 22
|
|
EGR
- 5
|
10
|
40
|
20
- 55
|
|
EGR
- 8
|
10
|
40
|
20
- 40
|
|
EGR
- 9
|
9,5
|
50
|
20
- 50
|
|
EGR
- 10
|
12
|
40
|
18
- 30
|
|
EGR
- 12
|
12
|
50
|
20
- 35
|
|
EGR
- 14
|
10
|
40
|
20
- 50
|
|
EGR
- 16
|
8,5
- 10
|
20
- 35
|
14
- 50
|
|
EGR
- 18
|
10
- 12
|
50
|
18
- 20
|
|
EGR
- 19
|
8
- 10
|
50
|
18
- 20
|
|
EGR
- 20
|
10
|
40
|
20
- 30
|
|
EGR
- 23
|
10
- 12
|
45
|
18
- 22
|
Phisical characteristics
of the electrographite materials could be determined using a tubes
of sizes 4x8x32 mm or 10x10x64 mm according to STAS 10223/1-75.
Fuctional characteristics: falling voltage, friction coefficient and middle
wear speed values
are determinated in laboratory conditions on two pieces of testing brushes
on sizes
12,5x25x40 mm according to STAS 10223/3-84. For the folling voltages, friction
coefficient
and medium wear speed values (point 6,7 and 8) are necesary the following conventional
conditions of testing:
|
TESTING
CONDITIONS
|
VALUES
|
|
peripheral
speeds
|
15
or 25 m/s
|
|
density
of current
|
15,
16 or 20 A/cm²
|
|
pressure
on brush
|
18-55
kN/m²
|
|
current
|
continous
|
|
temperature
|
60°C
|
|
|
