It usually appears at the RF, blade passage frequency and commutator brush frequency, and their higher harmonics.

它通常出现在射频，叶片通过频率和整流子刷频率，其高次谐波。

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Replacement brush: brush wear should not be used to change immediately, otherwise damage the commutator, more easily cause serious electrical burn.

调换电刷：电刷磨损到不能使用时应立即调换，否则会损坏换向器，严重时更容易导致烧坏电机。

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The no-brush direct current electromotor is a kind of direct current electromotor without any mechanical commutator or brush.

无刷直流电机是一种没有机械换向器和电刷的直流电机。

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