EMI suppression in permanent magnet DC motors having PCB outside motor in connector and overmolded

摘要

A permanent magnet DC motor 10 having electro-magnetic interference (EMI) suppression includes a metal motor housing 12 and a brush card assembly 34. The brush card assembly includes brushes 20 and leads 24 constructed and arranged to be coupled with a source of power to power the motor. A brush card housing 14 has a first portion 18 housing the brushes and a second portion 22, integral with the first portion, and housing the leads. A printed circuit board 26 is mounted with respect to the second portion of the housing and carries at least one electro-magnetic interference (EMI) suppression component 30 constructed and arranged to suppress EMI generated by the motor. The leads are electrically connected to the printed circuit board so that current can be provided through the printed circuit board to the brushes. A contact member 40 is electrically connected between the printed circuit board and the metal motor housing so that the at least one EMI suppression component couples the brushes to the metal motor housing thereby causing the metal motor housing to become an AC ground and EMI shield.