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Title: |
1921 Ad-Crawford Manufacturing Co., Squirrel Cage Electric Motor |
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Source: |
EMF electrical year book, Volume 1, 1921 page 485 |
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Insert Date: |
10/17/2011 8:27:24 PM |
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CRAWFORD MFG. CO., 13-21 Park Row. New York. N. Y. "Crawford" induction motors have certain operating features worthy of notice. They are guaranteed to carry their full rated load with a temperature rise not to exceed 40 degrees C above room temperature. Or they are capable of standing 25% overload for two hours or a momentary overload of 100%. All are subjected to rigid tests, such as breakdown tests of 1500 volts, temperature, efficiency and power-factor tests. The squirrel cage type here illustrated has a frame of the best gray iron, carefully machined and all parts interchangeable. The bearings are of "Non-Gran" bearing bronze, oiled by concentric rings from wells of ample capacity, protected by dust proof caps. The stator is made up of high grade laminae, compacted under pressure. Primary coils in semi-closed slots, held with one piece insulating wedge, insulated and protected with moisture and acid proof varnish. The rotor is of the squirrel cage type, the copper is forced directly through the iron without insulation, and end rings are cast-iron, of high-conductivity bronze, fusing the copper bars into a unit electrically perfect. The shaft is of special axle steel. These motors are equipped with sliding base and pulley when so ordered |
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1921 Crawford Manufacturing Co., Squirrel Cage Electric Motor
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