| 摘要 |
A universal motor has a stator, a rotor, brushes, and a filter circuit on a printed circuit board (PCB). The rotor has a shaft, a commutator mounted on the shaft, and a rotor core mounted on the shaft adjacent to the commutator. The rotor core is electrically connected to the commutator, and rotates within the stator. The brushes deliver electrical power to the commutator, and they elastically contact the commutator. The filter circuit reduces the emission of electromagnetic radiation from the universal motor, and is electrically connected to the brushes. The PCB is mounted over the brushes. When electrical arcing occurs between the commutator and the brushes, the PCB acts as a shield to absorb a portion of the radiation emitted by the arcing so as to reduce the EMI characteristics of the universal motor.
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