We know diesel generator from engine, generators and water tanks are assembled, and the generator brush generator and brushless synchronous generator. Has brush generator electric brush and the exciter electric brush resistance coefficient smaller, and performance compared stable, but by electric brush of pressure, and pass flow of size, and around environment humidity, and temperature, and clean degrees, and sliding ring surface and electric brush of wear degrees and electric brush itself manufacturing process, factors effect, in long-term run run in the, occurred electric brush flaming spent, even for electric brush reasons was forced to downtime of fault is often occurred of.
Generator brush blaze flowers for many reasons, practical reasons for using a brush blaze in the process spent the following four conditions:
1 And brush pressure differential or does not meet the requirements. Brush factory-manufacturer has relevant provisions: brush pressure is adjusted to minimum pressure spark does not occur, the minimum pressure is generally 200~300?/c? , That is, 0.02 ~ 0.03MPa And pressure should be uniform among the various brush. Uneven pressure in the following three cases:
( 1 ) Generator in the long run if a brush friction was too short, or brush in the brush box, card case with delays, pressures will have uneven;
( 2 ) The heated soft factors such as mechanical, spring itself, may also result in pressures up to brush without spark theory of minimum requirements;
( 3 ) And when we lift, impacting the carbon brushes alone, no experience, operation error is very large.
2 Bearing vibration. Run generator lead time, fatigue, aging, and more complex factors will cause increased bearing vibration, brush with vibration, uneven friction brush column, loose wire and spring, local flaming flowers slowly further influence global.
3 And brush current density is too large. In actual operation, if one or two brushes jam due to mechanical reasons, insufficient spring pressure causes no output, for the maintenance of normal load, current through the other brush will increase, increase flow if there is friction in the brush brush, due to contact with slip-ring area, contact surface flux density increases. According to Q=I*IRT, less heat is proportional to the square of the current, when the accumulation of heat dissipated, sharp increases in temperature, brush and slip ring contact surface will produce sparks. Sparks after the election, amidst the brush work, thus a vicious circle so that brush snapping more seriously, a few have this serious condition occurs when looping.
4 And brush the surface clean, and this is one of the most neglected. The normal operation of the generator brushes are sealed in a closed cabinet, polar brushes set in gear on the shaft axial-flow fan rotor wear under graphite powder, brush the heating time away, to clean the cooling effect. If the door doesn't stay closed, or patrol when closed, dust with the hot outside air into the brush, attach to the brush pole, effect brushes heat sink on the one hand, on the other hand brushes spark brush surface clean, brush between the dielectric strength easily Flash enough. In addition seal rings on the bus with a spirally grooved together, this is the heat dissipation area to increase the brush to improve contact with the brush, brush more adequate cooling, and easier for the toner out. If the door doesn't stay closed, fans are no longer available outside the dust very easily in a spiral groove, the consequences can be imagined. Excitor brushes to consider its relatively low voltage bare surface, also advise maintenance cleaning on a regular basis.
Others, such as brush polishing poor, poor manufacturing processes and brush out, contact resistance is too large, the gap is not uniform, high load, short circuits and other reasons, in actual use is also possible, but years of practice see above 4 Reasons, the majority of the points, with improved generator, has now started to use brushless generator, to reduce downtime caused by brush of failure.