Wind Power Carbon Brush Products
Newyard Carbon are now becoming the largest wind power carbon brush maker with an annual capacity of 200,000 pieces of phase brush and grounding brush. Positioned the upstream in the whole industrial chain,
we’ve been carbon brush supplier to one of leading wind turbine manufacturer in the world for 6 years, we are prepare to work with you and assist you with our engineering know-how.
Carbon Brush for Wind Turbines
Main (Phase) Carbon Brush
Lightning Transmission Brush
Earthing Carbon Brush (Generator)
Variable Pitch Carbon Brush
Main (Phase) Carbon Brush - Z50
Z50 Grade Wind Power Carbon Brushes - Main
Z50 grade material was specifically developed for Wind Turbine Generator application, because of its strict requirements under harsh operation environment. It has won the trust from both domestic and overseas customers due to its excellent durability during operation and compatibility with different OEMs.
Z50 Test Reports
Z50 was tested by National Quality Supervision and Inspection Center For Electrical Carbon Products – Accredited by CNAS, ILOC MRA.
The 50 hours test shows that the average abrasion of the Z50 is only about 0.05mm.
Please click here to download the full report.
Z50 Grade - Characteristics
Shore Hardness: 24
Flexural Strength: 38
Friction coef: 0.25
Current Density: 18
Lightning Transmission Carbon Brush Wind Turbines - D80
D80 Grade - Characteristics
D80 grade wind turbine carbon brush is specifically developed for lightning transmission from the blades to earth via hub, nacelle and tower.
Shore Hardness: 21
Flexural Strength: 30
Friction coef: 0.23
Current Density: 20
Earthing Carbon Brush - S50/X
S50 Grade - Characteristics
Shore Hardness: 25
Flexural Strength: 29
Friction coef: 0.25
Current Density: 18 (Silver / Graphite)
S50X Grade - Characteristics
Shore Hardness: 25
Flexural Strength: 28
Friction coef: 0.25
Current Density: 18 (Metal impegnation)
Wind Turbine Variable Pitch Carbon Brush - K50
K50 Grade - Characteristics
Shore Hardness: 90
Flexural Strength: 30
Friction coef: 0.20
Current Density: 12
Equivalent Grade of Wind Turbine Carbon Brush
The main factors causing failure in slip ring system on wind turbine generators
Ventilation of slip ring and carbon brush system
Slip ring and carbon brush produce sliding electrical contact during motor high speed rotation. The wear form of sliding electrical contact includes into electrical wear and mechanical wear. These wear will generate a lot of heat. If the heat cannot be taken away in time and effectively, the temperature of the slip ring surface and the carbon brush will rise sharply, causing the oxide film to thicken, and the contact voltage drop will increase. The wind turbine slip ring and carbon brush system are installed in the slip ring chamber. The protection level of the slip ring chamber is only IP23, and the space is relatively closed. Therefore, the ventilation and heat dissipation in the operation of generator slip rings and carbon brushes is particularly important.
Slip ring cooling generally uses axial fans, fans or the air volume of the air outlet of the motor air cooler to cool the slip rings and carbon brushes, and at the same time exhaust the air with carbon powder to the carbon powder collector in the lower part of the engine room. Therefore, it is necessary to ensure that the cooling air path is unobstructed and the effective value of air volume and pressure can be achieved in order to achieve the cooling effect.
Wind turbine carbon brush selection and installation
During the selection of wind turbine carbon brush products, attention should be paid to the matching of carbon brushes and slip ring materials. Carbon brushes from different manufacturers and models have differences in conductivity and hardness. If the material is too hard, it directly affects the dynamic and static contact surfaces of the slip ring and the carbon brush itself, increasing the friction of the slip ring and causing damage to the ring surface; the material is soft, the carbon brush is very easy to wear, frequent replacement, and increased maintenance costs. Another aspect is that carbon brushes of different materials are used for different environments. Generally, they are divided into three types: materials for low altitute, material for high altitute and marine material.It is more reasonable to choose suitable carbon brushes for different operating environments of wind turbines.
The carbon brush cannot be installed too tight or too loose in the brush holder. Too loose will cause the carbon brush to vibrate in the brush holder, resulting in poor contact with the slip ring; too tight will affect the free sliding of the carbon brush in the brush holder, and “stuck” will occur in severe cases. Generally, the reasonable gap is 0.1mm. At the same time, pay attention to the installation angle of the brush holder to be concentric with the slip ring to avoid partial wear of the carbon brush.
Influence of spring pressure
The function of the constant pressure spring is to provide the contact pressure between the carbon brush and the slip ring to ensure reliable and effective contact between the two. When the pressure is too small, although the friction coefficient can be reduced and the pure mechanical wear is reduced, the electrical wear will greatly increase, which will affect the conductivity of the carbon brush; when the pressure is too high, the conductivity will increase, but the mechanical wear will increase. Therefore, the wind turbine carbon brush pressure should be controlled within a reasonable range. Generally, according to the material of the carbon brush used in wind power, the main carbon brush is 200cN/cm2±10%, and the ground carbon brush is 250cN/cm2±10%. However, because the constant pressure spring is used under high temperature and vibration for a long time, the pressure attenuation is inevitable. Therefore, regular testing should be done for those with a long service life to ensure that the pressure is qualified.
The influence of carbon brush current
The rotor current value of the wind turbine is large, which requires number of carbon brushes to be arranged in the same phase for drainage. Due to differences in carbon brush material, spring pressure, and contact resistance, the current value deviation between the carbon brushes will be large. The current density of individual carbon brushes exceeds the maximum allowable value, causing serious heating of the carbon brushes, destroying the oxide film, and causing the ring surface Burned.
The influence of slip ring radial runout
Slip ring eccentricity, bearing failure, motor assembly and other factors can easily cause radial runout, which makes the contact between the wind turbine carbon brush and the surface of the slip ring unstable. The sliding contact of the carbon brush will deteriorate, and large sparks are likely to be generated, resulting in the carbon brush surface is easy to burn, destroy the oxide film, and aggravate the wear of the carbon brush. When the motor vibrates seriously, it will not only aggravate the mechanical wear, but also cause fatigue fracture of the constant pressure spring, damage and cracking of the carbon brush, and burn the slip ring.
Impact of operation environment
The operating environment of wind turbines covers almost all climatic conditions. Coastal and plateau environments have the greatest impact on slip rings and carbon brushes. Due to the high moisture content in the air in these two types of areas, especially in the plateau environment, the condensation phenomenon is serious, which has a great impact on the oxide film on the surface of the slip ring. A good oxide film will improve the contact between the slip ring and the carbon brush, play a lubricating effect, and improve the wear resistance of the carbon brush.
When the absolute humidity is greater than 20g/m3, excessive air humidity will aggravate the formation of oxide film, which will increase the thickness of the oxide film, increase the contact pressure of the carbon brushes, increase electrical losses, and cause the carbon brushes to overheat and cause ignition. , And burn the slip ring. Therefore, it is particularly important to control the humidity inside the slip ring chamber in plateaus and coastal areas.
1. In the slip ring chamber, the carbon powder on the brush holder gap and the brush holder is severely carbonized, causing creepage, ignition, and burning of the carbon brush.
2. The carbon brush contact surface has not reached more than 80% for grid-connected operation, resulting in insufficient contact surface, excessive carbon brush current density, and heat generation and ignition.
3. The carbon brush alarm switch is damaged, causing the carbon brush to wear out and fail to give an alarm in time. The carbon brush wear exceeds the warning line and rubs against the chamber ring to cause a malfunction.
4. Serious carbon deposits in the toner filter at the lower part of the slip ring chamber caused blockage of the cooling air passage and increased temperature in the slip ring chamber, causing malfunctions.
5. The grounding carbon brush braid joint is loosely connected and the grounding wire is broken, causing the carbon brush to burn out, the motor shaft current cannot be effectively exported, and the bearing is galvanized.