Analysis on the causes of carbon brush fault of generator set

In recent years, several safety briefings have successively reported shutdown accidents caused by carbon brush or rotor collector ring failure of large generator units, resulting in great economic losses to the enterprise.Carbon brushes are motor brushes. Improper maintenance and use of the carbon brush of the generator set during operation will cause accident load reduction or even shutdown.

     Electromagnetic factors : when reactive or excitation current is adjusted, the spark of carbon brush has obvious change. When the exciter commutates, the contact between the carbon brush and the commutator is not good, and the contact resistance is too large ; the uneven thickness of the oxide film of the rectifier or slip ring causes the unbalanced distribution of carbon brush current ; or sudden change of load and sudden short circuit lead to abnormal voltage distribution between commutators ; unit overload and imbalance ; carbon brush selection is unreasonable, carbon brush spacing is not equal ; carbon brush quality issues, etc.

Mechanical factors : commutator center is not correct, rotor imbalance ; large vibration of the unit ; insulation bulge between commutators or commutators bulge ; carbon brush contact surface grinding is not smooth, or commutator surface roughness caused by poor contact ; the commutator surface is not clean ; the air gap under each reversing pole is unequal ; spring pressure on carbon brush is uneven or unsuitable ; carbon brush in the brush grip too loose and jump, or too tight carbon brush in the brush grip stuck, etc. Reduced operating speed or improved vibration will reduce sparks.

Chemical factors : When the unit is running in corrosive gas, or the unit is running in lack of oxygen, the copper oxide film formed naturally on the surface of the contact surface between the commutator and the carbon brush is destroyed, and the commutation of the formed approximate linear resistance does not exist, and the spark of the commutator is intensified in the process of forming the oxide film on the contact surface. The commutator ( or slip ring ) is corroded by acid gas or oil. Carbon brushes and commutators are contaminated.

The pressure of the carbon brush spring should conform to the manufacturer ‘ s regulations, so that the pressure of the carbon brush is uniform. The carbon brush spring produced by Qianye maintains the same pressure with the rectifier regardless of the length of the carbon brush. Larger rectifiers can be used to reduce sparks and electromagnetic interference.

     Shenzhen Qianye Precision Metal Co., Ltd. is a manufacturer specialized in providing high-precision springs. The company integrates product R & D, production, sales and services, and has engineering and management personnel with various technical skills and rich experience. Has successfully passed ISO9001, ISO14001 and TS16949 professional qualification certification. We sincerely welcome new and old customers and friends from all walks of life to visit the company to guide, negotiate business cooperation, Qianye Precision will sincerely serve you !