Electric Lighting: A Practical Exposition of the Art, for the Use of Engineers, Students, and Others Interested in the Installation or Operation of Electrical Plants, Volume 1
Electric Lighting: A Practical Exposition of the Art, for the Use of Engineers, Students, and Others Interested in the Installation or Operation of Electrical Plants, Volume 1
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. 1896 edition. Excerpt: ...a dynamo having a capacity equivalent to the maximum power of the windmill, the two being mechanically connected by belting or gearing. It is also necessary to apply some automatic device which will cause the dynamo to charge the storage battery only when its speed and voltage rise above a certain value. This ...
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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. 1896 edition. Excerpt: ...a dynamo having a capacity equivalent to the maximum power of the windmill, the two being mechanically connected by belting or gearing. It is also necessary to apply some automatic device which will cause the dynamo to charge the storage battery only when its speed and voltage rise above a certain value. This device may be either mechanical or electrical. For example, a centrifugal governor can be combined with a switch so as to close the latter when the speed reaches a certain limit, and open it when the speed falls below this value; or an electromagnetic device may be adopted which will close the circuit when the voltage of the dynamo rises to the proper point. If such a device were not used, the battery would discharge back through the dynamo when the voltage of the latter fell below the E.M.F. of the former. Another device to maintain a reasonably constant voltage with wide variations in speed consists in winding the field-magnets of the dynamo differentially; that is, with a series-coil which opposes the magnetizing effect of the shunt-coil, so that, as the speed of the dynamo and the current which it generates increase, this series-coil will tend to demagnetize the field and keep down the E.M.F. of the dynamo. This would seem to be a simple and effective means of producing an approximately constant voltage with the very great changes in speed which would always occur in windmill plants. It has been proposed to employ other methods for the storage of energy in place of the secondary battery;' for example, the windmill may be arranged to pump water up to a tank, by which supply a water motor could be operated. In this way a constant head of water and speed of dynamo could be maintained; but the size and cost of a tank or reservoir...
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