In huge area of the wind plant, the Wind Power Generating Set likes an inexhaustible giant to transform the natural wind power into a continuous green one. When we are amazing the fact that the blade can accurately capture the wind or that the motor can high-effectively operate all the time, those precise and indispensable components are generally to be ignored where are installed in the cabin. The Brush Holder, as one of those important components, can provide the carbon brush a "suitable house" and "the source of the power", in spite of its small structure, for the purpose of ensuring the motor stable operation.
- Solid "bodyguard" for ensuring the fact that the current can stable and smooth transmit
The slip ring of the motor is responsible for transmitting the current and the signal between the rotating rotor and the static stator. During that process, the carbon brush acts as the direct contact medium and the brush holder is the carrier of that carbon brush. And, the core role of the brush holder remains the stable and solid mechanic support. It should ensure the fact that the carbon brush can keep the constant pressure on the surface of the high-speed-rotating slip ring with the effects on neither too loose to make the carbon brush vibrating nor too ineffective contact to generate arc or too tight to make the carbon brush jammed or too worn. Only the fact that the functions of the directional guiding and the position limit of the brush holder can be perfectly operated, the carbon brush can tightly contact with the slip ring to ensure some core data with lossless and stable transmitting, including exciting current and pitch control signals.
- Accurate "pressure regulating valve" for maintaining desired oxidation film
During the long friction process of the carbon brush and the slip ring, an extremely thin layer of the "oxidation film" will be generated between those two surfaces. Thanks to that film, its fiction coefficient will be reduced, its reversing performance will be improved and related electric sparking will also be reduced as well, so that film is called "the lubricant" and "the protective umbrella" of the motor. Inside the brush holder, there is a constant-force spring with its excellent performances of uniform and continuous pressure output according to the wear of the carbon brush. Therefore, the above-mentioned dynamic pressure-adjustment mechanism plays the core role in maintaining its oxidation film generation and replacement with a sound level. If the unbalanced pressure of the brush holder, its oxidation film will be destroyed, leading to the surface of the slip ring injured or to the abnormal wear of the carbon brush or even to be harmful for the electric equipment.
- The sharp-eyed sentry for a smart monitoring and perfect safeguard
The brush holder of the modern motor acts as not only a mechanic fixing part but also an important part of the smart operation. Many advanced brush holders integrate their micro-switch monitoring equipment which functions the "health sentry" for the slip ring system. When the carbon brush is worn to its safety limit or the constant spring inside the brush holder is loosened or ineffective, its micro-switch will sharp-eyed capture the change of the mechanical displacement and then send the precaution signal for its main-controlled system. Thanks to that remote control performance, the maintenance staff can repair and replace the carbon brush in time before complete worn-out or arc or electric sparking, which can extremely reduce the economic losses generated by the non-preplanned halt.
- Preventing itself against the harsh environment
Owing to the exposure of the motor throughout the year, it is faced with a serious of harsh environments such as high-salt-and-spray corrosion, extreme temperature differences, high moisture and carbon powder accumulation. Therefore, extremely-high corrosion level and mechanic strength should be required for the brush holder and its inner metal components for the purpose of preventing itself against the harsh environments. Meanwhile, the structure design of the brush holder should also be considered the clean and the expelling for the carbon powder, avoiding interphase short circuit generated by its conductive carbon powder accumulation inside the brush holder. An excellent-designed brush holder likes the armour of the carbon brush to ensure itself stable operation under the complex conditions.
In conclusion, the brush holder acts as multiple roles in supporting, adjusting, monitoring and preventing for the motor. As the footstone of the effective operation, the carbon brush also remains the backstage hero for the safe and effective operation of overall slip ring system. At present, the human being is pursuing for more effectiveness and longer service life for the motor. Therefore, the top priority should be given to the emphasis on optimized design and manufacture for the brush holder, which will doubtlessly become the indispensable ring for improving overall motor equipment reliability.
