# Electrical and Magnetic Calculations; For the Use of Electrical Engineers and Artisans, Teachers, Students, and All Others Interested in the Theory and Application of Electricity and Magnetism

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## Description

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1903 edition. Excerpt: ...supply an alternating current. What would be the E.M.F.? Solution.--2 dnv 2 X (6X io6) X 200 X 41 E =---= ' = 1000 volts. IO8 IO8 Example.--Determine the electromotive force of a 6-pole alternator running at 2100 r.p.m., the flux being 24 X io6 webers and there being 200 wires on the armature. Solution.--_ 2 mfk _ 2 X 24 X ioDX 200X35 X3X1.11 io8 io8 = 1118.8 volts. Example.--What must be the number of webers of flux furnished by each pole of a machine similar to the last for 560 volts, and what cross section of poles? Also what width of poles to be equal to one-half the pitch? Solution.--Ex io8?6oX io8 d = =--=1,201,200 webers. 2.22 nf 2.22 X 200 X 3 X 35 For dynamo poles B may be, say 12,000 gausses. Hence A 1,201,200 A = = =100 so. cm. B 12,000 The circumference of the pole circle is very nearly 80 cms. Since there are 6 poles and the distance apart is equal to the width, each must be 80.+. 12 = 6.66 cms. The length of pole face and armature core must then be 100--6.66 =15 centimeters. 46. Multipolar Direct Current Dynamos.--The usual method of winding Gramme ring armatures is to wind the different coils the same way continuously around the ring. Now when the coils are joined together, the end of the first may be joined to the beginning of the second, the end of the second to the beginning of the third, etc. There will then be as many brushes and as many armature circuits as poles. This is called the multiple winding. Thus a 4-pole machine requires 4 brushes--two pairs at right angles, and 4 circuits in the armature all in parallel. Evidently the brushes of like polarity may be connected together, thus putting all the current in a single external circuit. Also the coils may be so cross conne ted at the commutator end of the armature as...show more

## Product details

• Paperback | 64 pages
• 189 x 246 x 3mm | 132g
• Miami Fl, United States
• English
• black & white illustrations
• 1236614941
• 9781236614940