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Title: |
1909 Article-Electro-Dynamic Co., Interpole Variable Speed Electric Motor |
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Source: |
Cyclopedia of Applied Electricity, 1909 pgs 430-433 |
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Insert Date: |
11/2/2011 7:43:10 PM |
Electro-Dynamic Company — A prominent type of adjustable speed motor is that of the Electro-Dynamic Company in which speed variations from 6 to 1 may be obtained by field weakening. Sparking is prevented by the employment of interpoles; that is, auxiliary poles, small compared with the main poles, are located between the latter and provided with coils connected in series with the armature. The flux of these interpoles is in direct opposition to that o the armature and gives the commutation field. Since the coils of the interpoles are connected in series with the armature, the commutation field is not affected by weakening the shunt or main motor field to obtain the increased armature speeds. It is, furthermore, proportional to the load, thus producing sparkless commutation at all loads and speeds within the limits of the design of the machine. As the action of the interpoles is reversible, the motors can be run equally well in either direction. Fig. 80 is a view of one of these motors with the bearing housings and armature removed, showing the interpoles. These motors are manufactured in sizes from ½ to 75 H. P. as 4-pole machines, and in sizes from 40 to 150 H. P. as 6-pole machines, operating on 110-, 220-, or 500-volt circuits.
The field yoke, except in the largest frame, is of best electrical steel in one piece. The main poles are cast steel or laminated, as required, bolted to the yoke, and the interpoles are of wrought iron. The ball bearings used have two races, for the balls, one fastened directly to the armature shaft and the other free in the bearing housing. The kind of bearing is shown in Fig. 81, and since the lubricant is Vaseline or other heavy lubricant, the machine can be placed in any position. This motor is, of course, also manufactured in semi-enclosed, enclosed, and vertical types. Fig. 82 shows one of the many applications of this machine. |
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1909 Electro-Dynamic Co., Interpole Variable Speed Electric Motor
1909 Electro-Dynamic Co., Interpole Variable Speed Electric Motor Field Coils
1909 Electro-Dynamic Co., Interpole Variable Speed Electric Motor Armature
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