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Title: |
1895 Article-Elektron Mfg. Co., 20 HP Perret Electric Motor |
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Source: |
Modern Mechanism 1895 pgs 542-543 |
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Insert Date: |
9/5/2011 9:49:28 PM |
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The chief distinctive feature of the motors designed by Frank A. Perret is the lamination of the field magnet, which is built up out of thin plates of soft charcoal iron, stamped directly into their finished form, and clamped together by bolts in such a manner as to secure great mechanical strength. The armature core is also laminated, and the plates have teeth which form longitudinal channels on its periphery, in which the coils are wound. Fig. 11 is a side view of a 20 horse-power motor complete Fig. 12 is a cross-section of magnets and armature showing magnetic circuit. It will be seen that the armature is a ring of comparatively large diameter, with longitudinal channels on its periphery, in which the conductors are wound and thus embedded in the iron, which is in such close proximity to the iron pole pieces that there is practically no gap in the magnetic circuit. The field consists of three separate magnets arranged at equal distances around the armature, each magnet having two pole pieces. The winding is such as to produce alternate north and south poles. The magnets arc built up of plates of soft charcoal iron, which are shaped as shown in the diagram, and the magnet thus produced is of such a form that it may be readily wound in a lathe. A non-magnetic bolt passes through a hole in each pole-piece, and the plates are clamped together between washers and nuts on the same. These bolts also serve to attach the magnets to the two iron end frames, which are of a ring shape, and are bolted to the bed plates of the machine. The magnetic circuit is of unusually low resistance by reason of its shape, its shortness, which is shown by the diagram, and the superior quality of iron used. There is no magnetism whatever in the frame, bed, or shaft of the machine, as the magnets are supported at some distance from the frame by means of the nonmagnetic bolts, and the armature is mounted on the shaft by spiders of non-magnetic metal. |
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1895 Elektron Mfg. Co., 20 HP Perret Electric Motor
1895 Elektron Mfg. Co., 20 HP Perret Electric Motor Cross-Section
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