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. 1893 Excerpt: ...of this equation, when tj is taken equal to 180 (that is, the E. M. F. is introduced when the normal current curve is zero), is shown in Fig. 35. It will be noticed that the initial value of the logarithmic curve has considerable variation according to the particular point of time at which the E. M. F. is introduced. ...
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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. 1893 Excerpt: ...of this equation, when tj is taken equal to 180 (that is, the E. M. F. is introduced when the normal current curve is zero), is shown in Fig. 35. It will be noticed that the initial value of the logarithmic curve has considerable variation according to the particular point of time at which the E. M. F. is introduced. This variation is represented in the curve IV., Fig. 35. The initial value of the logarithmic decrement at 0 or 180 is almost twice as much as the.955 maximum value of the current /, their ratio being.' r. The equation, when;/-, is 180, reduces to _ a-to (21G) i =.5 sin f-.955 e 08 sin!955(--t, ) + x. In each of the above examples the current follows the sine law in about one-quarter of a second after the periodic E. M. F. is introduced, during which time somewhere in the neighborhood of forty oscillations have been made. The phase at tohich the E. M. F. should be introduced to make the oscillation a maximum: --It may be interesting to inquire at what point the E. M. F. should be introduced into the circuit to render the effect of the oscillation a maximum. This point may readily be found by referring to equation (212). The coefficient of e becomes a maximum (for a variation in when the quantity under the radical sign is a maximum. Differentiating the quantity under the Fig. 36.--Showing How To Find Geometrically The Angle $l Which Makes The Effect Of The Exponential Term A Maximum. radical, then, with respect to tlt and equating to zero, we obtain (217) (Z Coo1'-l)aiii2 01 + i?C/a cos 2 f, = 0. Whence tan 2 ip, = =--: --S--' 1-Li Ci G0 But it will be remembered that see equation (190) Hence tan 2 tpl = cot 6 = tan--#) (218) or 0, = f--J. And since = coi, --6 see (138), we find (219) f-T1 Suppose 0 is an angle of lag of--75, as in the first ex...
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Choose your shipping method in Checkout. Costs may vary based on destination.
Seller's Description:
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