| 摘要 |
This invention relates to a speed changing device, giving at least two motor speeds, for an electric motor supplied with direct current. It is applicable to motorized ventilating fan units designed for the air cooling of heat engines, mainly for automobiles. The speed changing device is characterized in that it includes a contactor having at least two positions whereby, in the first position of the contactor, not more than three of the brushes are supplied with electrical current so as to obtain a first motor speed (low speed), while in the second position of the contactor, all of the brushes are supplied with electrical current so as to obtain the greater motor speed (high speed).
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