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. 1911 Excerpt: ...which largely eliminated that class of trouble though still leaving the arrester subject to damage at times. Another form of arrester, which is illustrated in Fig. 80, embodies with gap and resistance a shunted solenoid so arranged that the plunger is raised by the passage of the dynamo current, thus opening the ...
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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. 1911 Excerpt: ...which largely eliminated that class of trouble though still leaving the arrester subject to damage at times. Another form of arrester, which is illustrated in Fig. 80, embodies with gap and resistance a shunted solenoid so arranged that the plunger is raised by the passage of the dynamo current, thus opening the circuit. This type is subject to trouble, due to the puncture of the insulation of the solenoid winding which destroys the circuitbreaking feature and permits the dynamo current to flow uninterruptedly until the circuit opens elsewhere or the apparatus has burned itself clear. However, both of these types have been used in great numbers in American practice with good results as far as the protection of the apparatus is concerned. A modification of the spark gap and resistance type of arrester has been worked out for 2300-volt circuits with a Fig. 81. Multi-path Lightning Arrester. considerable degree of success. It is illustrated in Fig. 81 and consists of three paths of discharge, one of which has a resistance of about 100,000 ohms, another a resistance of about 300 ohms and another which consists of 13 or 14 gaps without resistance. The inductance and capacity of the parts is such that very high frequency discharges pass over the 13 gaps, while lower frequency potential risers pass over the smaller number of gaps through one of the resistances. The use of an aluminum cell as a lightning arrester has offered promising results because of its ability to choke the generator current upon the first alternation and thus prevent damage. It has been found especially valuable on transmission voltages where its expense is justified by the importance of the service. It is not suited for outdoor distribution work since it requires daily charging and supervisio...
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