| 摘要 |
An electric fan includes a fan shaft driven by a fan motor supported by a motor support. An oscillating device includes a rotational shaft connected to the motor support for driving the motor support to oscillate. A transmission gear has an axle connected to the rotational shaft and a gear wheel mounted around the axle and driven by a synchronous motor. An oscillating angle limiting switch detects a rotational angle of the rotational shaft and the gear wheel and sends a signal indicative of the rotational angle. A circuit board has a processor coupled to the oscillating angle limiting switch and receives the signal. A comparing program compares the rotational angle indicated by the signal with a selected one of a plurality of preset rotational angles. The synchronous motor is driven when the rotational angle indicated by the signal is equal to the selected preset rotational angle.
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