Hit or Miss
Bric-a-brac: Ediswan NE.1002 20 KV Voltage testing stick - Information wanted
long by 26 mm width
glass tube with narrowed middle neck, brass and copper ends
20,000 volts Max
|This particular device was a high voltage indicating test stick used in and around 1953 in UK power stations. The only one on the web so any more information would be greatly appreciated. This item was kindly donated to this web museum by Janice Twidale (and in kind memory of her father) - thank you.|
I cannot find out any official information about this so here is my info based on some chats and assumptions.
A dumbbell shaped valve with a narrow middle section. The "NE" prefix suggests that is is filled with neon gas.
The top brass node appears to be connected to a circular internal node whilst the bottom copper node has no internal connections at all and is insulated by the glass bulb.
The device would probably have been used in some more elaborate "measuring stick" device, so I think this was a plug-in component.
The design would be consistent with a neon gas discharge tube which you would expect to glow at high voltage, the narrowed neck accentuating the plasma glow and hence making the indication of high voltage easier to see. Therefore you would earth the brass (cathode?) end and use the copper end to sense high voltages (which is probably rounded to stop corona (thanks Mike)).
Accompanying the valves is an Ediswan Industrial Valve Service Report Form (Form 1309 Revised).
This 365mm x 203mm thin sheet had to be filled in with quite a bit of detail to return a faulty valve. Such things as model and serial number of the equipment it was in, numbers of hours of use, filament voltage when in standby mode etc.
The return address was The Edison Swan Electric Company Ltd., Radio Stores, Ponders End, Middlesex, England.
This example (of two valves) comes with the original shipment box to a power station dated August 1953.