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Lot of 960 GEC Gas Filled Arresters for Telephone Line Protection Made in England by the M-O Valve Co. The item itself says the following: The type 17B is a three electrode gas-filled surge arrestor in a ceramic and metal envelope. In use, the middle electrode is grounded and each end cap connected to a line thus providing a spark gap from each line to ground and also one between lines. As the three electrodes are adjacent, the firing of any gap initiates the firing of the other two. This gives a better approach to simultaneous operation when excess voltages, either balanced or unbalanced appear on both lines than can be obtained using three separate two electrode arrestors. Insulation Resistance at 85 VDC A typical arrestor will show only slight changes in characteristics after being subjected to 10 current surges of 8/20 waveform, 20 kA peak at one minute intervals through one gap (5 surges in each direction). In particular the dc striking voltage will usually remain within the limits shown and the surge striking voltage will usually not rise to more than 200 V above the limit shown An 8/20 waveform is one what rises from zero to peak value at t=8 microseconds and decays to half the peak value at 20 microseconds. (typical surge from nearby lightning strike) (New lot OF960 gec gas filled telephone surge protectors was posted and is owned by: Patrick Erickson) |
perickson@chicagopartsnetwork.com (Patrick Erickson) for more information.
