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. 1920 Excerpt: ...and p = the resistivity of the iron in ohms per centimeter cube. All other quantities are described under hysteresis loss. If the armature core were solid the e.m.f.'s generated in the rotating core would cause currents to flow in the iron as shown in Fig. 72. By constructing the core of iron sheets (called laminations ...
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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. 1920 Excerpt: ...and p = the resistivity of the iron in ohms per centimeter cube. All other quantities are described under hysteresis loss. If the armature core were solid the e.m.f.'s generated in the rotating core would cause currents to flow in the iron as shown in Fig. 72. By constructing the core of iron sheets (called laminations) insulated from each other electrically as shown in Fig. 73 the ratio of the e.m.f. to the resistance in each lamination is reduced and the eddy current loss is materially diminished. The laminations are punched from soft sheet iron, 0.015 inch or more in thickness, and are insulated by the natural surface oxide or by a coat of varnish. Determination of the Rotational Losses in a Dynamo. The rotational losses are usually determined experimentally by operating the dynamo as a shunt motor at no load, as in Fig. 74. The input to the armature (VJa) minus the armature copper loss (IaRa) minus the rotational losses (PT) equals zero or VJa--IaRa--Pr = 0 and Since the rotational losses depend upon the speed and the flux density the rotational losses corresponding to any stated load are determined by operating the motor at no load at the same speed and flux density as at the stated load. If the mechanical output (P0) of a motor operated under load may be measured accurately the rotational losses may be determined by 82 PT = VJa-Ia2Ra-Po Watts. The Efficiency of a Dynamo. The efficiency of a generator or a motor equals the ratio of the power output to the power input. The efficiency of a generator is then given by the ratio of the power output to the sum of the power output and the losses. Hence the efficiency of a generator is given by VJi The efficiency of a motor is given by the ratio of the power input minus the losses to the power input or VJ, -VJ, .
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PLEASE NOTE, WE DO NOT SHIP TO DENMARK. New Book. Shipped from UK in 4 to 14 days. Established seller since 2000. Please note we cannot offer an expedited shipping service from the UK.
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PLEASE NOTE, WE DO NOT SHIP TO DENMARK. New Book. Shipped from UK in 4 to 14 days. Established seller since 2000. Please note we cannot offer an expedited shipping service from the UK.
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PLEASE NOTE, WE DO NOT SHIP TO DENMARK. New Book. Shipped from UK in 4 to 14 days. Established seller since 2000. Please note we cannot offer an expedited shipping service from the UK.
Choose your shipping method in Checkout. Costs may vary based on destination.
Seller's Description:
PLEASE NOTE, WE DO NOT SHIP TO DENMARK. New Book. Shipped from UK in 4 to 14 days. Established seller since 2000. Please note we cannot offer an expedited shipping service from the UK.
