| 摘要 |
The vertical drill has a support stand with a horizontal work table at its base and supporting a drill head moved vertically along the stand. The drill head incorporates a hand wheel, rotated to control the vertical displacement, an electric drive motor and a driven tool shaft. The drive motor comprises a DC motor with a permanent magnet rotor which is supplied from the AC network via a rectifier. The latter is in series with a setting control allowing adjustment of the motor rotation rate. Pref. the motor is incorporated in the drill head between the driven shaft and the stand, with a mechanical transmission between the motor and the shaft. The DC motor is compact and has a precise rotation rate for obtaining high quality bore holes.
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