Characteristics of Arc-Reducing Effect by Capacitor in Commutation Circuit

Ryoichi HONBO  Youichi MURAKAMI  Hiroyuki WAKABAYASHI  Shinji UEDA  Kenzo KIYOSE  Naoki KATO  

IEICE TRANSACTIONS on Electronics   Vol.E89-C   No.8   pp.1153-1159
Publication Date: 2006/08/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e89-c.8.1153
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Recent Development of Electromechanical Devices (Selected Papers from IS-EMD2005))
Category: Arc Discharge & Related Phenomena
commutation,  arc,  capacitor,  brushes,  equivalent commutation circuit,  

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DC motors are indispensable to improve the automotive functions. Recently, 70-100 motors are installed on luxury cars and this number is increasing year by year. With the recent demand for improved fuel economy and better equipment layout, the improvement of the motor's efficiency and the minimization of the motor size are the key to enhancing the competitive edge of the products. Adopting the high-density coil is an effective method for that, but it is accompanied by the commutation inductance rise which causes the commutation arc increase. The increase of commutation arc decreases motor life, because it causes the rise of brush/commutator wear. This report describes an arc-reducing effect obtained when capacitors are built into a commutation circuit for the purpose of reducing arcing under high commutation inductance conditions. The results of an evaluation using a equivalent commutation circuit and carbon brush/carbon flat-commutator showed that although a commutation circuit with built-in capacitor generated the same arc energy as a commutation circuit without a capacitor above a certain value of residual current, it displayed an excellent arc-reducing effect below that value of residual current.