. Garton-Daniels and Keystone lightning protective apparatus. . rester is sealed at the top, the only outlet for thisexpanding air is down the air chutes in block P and through themain expulsion gap R. This sudden blast of air blows out thearc in nap R, and this being interrupted, thearcs between discharge caps J-J-J-J simply die out. It will at once be seen how entirely au-tomatic and positive this method of arc ex-tinguishment is; if the flow of dynamic cur-rent is slight, the heat created within thearrester is small, the expulsion effect issmall and the air gaps are entirely suf-ficient to
. Garton-Daniels and Keystone lightning protective apparatus. . rester is sealed at the top, the only outlet for thisexpanding air is down the air chutes in block P and through themain expulsion gap R. This sudden blast of air blows out thearc in nap R, and this being interrupted, thearcs between discharge caps J-J-J-J simply die out. It will at once be seen how entirely au-tomatic and positive this method of arc ex-tinguishment is; if the flow of dynamic cur-rent is slight, the heat created within thearrester is small, the expulsion effect issmall and the air gaps are entirely suf-ficient to extinguish the flow at the end ofthe first half cycie of the generator the flow becomes heavier we still de-Figure 6—Details of Expulsion pend to a certain extent on the arc-ex- Gap of Expulsion Arrester tinguishing properties of the air gaps, but this heavier flow creates more heat and causes a heavier blast of airto be expelled through expulsion gap R. And with still heavier flows we get a still heavier blast of air through the main expulsion 12. ELECTRIC SERVICE SUPPLIES COMPANY KEYSTONE LIGHTNING ARRESTERS Expulsion Type gap R to assist the air gaps in extinguishing the flow of current toground. The heating value of a current depends on the square of its value(H=R if, therefore, we get any certain expulsion blast with any given current, if we double the current, we will get four times the heatingeffect and up proximately four times the expulsive effect of the first blast,if we have four times the current we will get sixteen times the heatingeffect and approximately sixteen times the expulsive effect of the firstblast. Therein lies the peculiar and unique feature of the Expulsion Ar-rester ; by means of its construction it is possible to secure a highlyefficient arrester, both from the standpoint of low arc-over value onaccount of the small air gap distance used, and high discharge capacitybecause of the low series resistance employed; and at the same time^ccure
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectdivisio, bookyear1921
