Nicholson Arcing Rings Sold by Locke

THE NICHOLSON ARCING RING.

The Nicholson Arcing Ring which has been taken over exclusively for manufacture and sale by The Locke Insulator Mfg. Co. of Victor, N. Y., is apparently a near approach to the solution of much of the lightning trouble upon power transmission lines. Ordinarily, after a lightning storm, a lineman finds the insulator shot to pieces and it is usually construed as a punctured insulator. The fact probably is that due to an indirect stroke of lightning, that is to say, within a matter of a quarter of a mile or less of the line, surges have been induced upon the line causing the insulator to flashover and the power arc which follows, being naturally concentrated under the shells of the insulator is grounding to the pin, mechanically ruptures the insulator due to the concentrated heat of the arc and after the shells are thus cracked from this heat the current follows, creating the destructive effect noticed. Upon this analysis the arcing ring was based and its use up to the present time shows it to be correct. The installation of arcing rings allow flashover to take place between the upper ring, which is grounded to the cross-arm or pin and the lower ring is so removed from the insulator as to avoid the heating above referred to. After the circuit breakers have gone out it has been demonstrated that the line can be tied in again and the insulators are intact. This result is of course very gratifying as compared with the old condition of finding the line grounded through ruptured insulators, in which case it was necessary to send out linemen to make repairs before operation could be resumed. It will be immediately apparent that these appliances are specially valuable in the case of an important power load being carried on a single circuit where the load cannot be transferred to a duplicate line. Or it is valuable again in the case of isolated, inaccessible portions of a line where repairs are laboriously and expensively made.

Nicholson Arcing Ring

The most conspicuous example of the use of these rings has been in the case of the Niagara, Lockport & Ontario Power Company and Mr. Nicholson presented the features of this installation to the American Institute at the Charlotte meeting last year.

Diagram of Nicholson Ring

Very many ideas have been held regarding the service to be performed by high voltage insulators; some engineers intend them to serve as an absolute preventative of line discharges, depending upon lightning arresters and ground wires; others have considered making the insulator rugged enough to remain intact as a result of flashover, intending such line flashover to save destruction in the power house, but in no case has it been shown that it is safe to consider the insulators other than special pieces of apparatus which are in a sense frail and should be protected against destructive discharges as in the case of any other piece of apparatus.

Pierson, Roeding & Company of San Francisco, Portland, Seattle and Los Angeles, is the Pacific Coast representative for the Locke Insulator Mfg. Co.