Bicone switch problem solved ?
By Darrell Clarke
G'day all,
A good deal of very useful information has been posted on electrical problems in restoration and I hope someone can crystallise it into a helpful guide or FAQ. For those who have been troubled by the "bi-cone" push-pull switch used by Aeolian, I think I have cured the erratic behaviour of mine very simply. The basic design is quite sound, the problem seemed to be the excess travel of the cones in the "on" postion. I corrected this by inserting a thin fibre washer into the well in the insulating block which carries the fixed contacts. This well has the spigot which guides the cones and determines the travel of the pull shaft. For safety reasons, the washer must be insulating and in my case, about 0.5 mm (20 thou.) thick seems about right.
I must mildly disagree with Craig about this switch, I think it has a good wiping snap action and should have a long working life if it is set correctly as above. A broken spring would be the trickiest bit to repair, but not impossible. It has no pivots to wear or get out of alignment and is one switch I would not discard.
Something to be bourne in mind when contemplating replacement with modern parts, particularly solid state electronics, is can it be repaired again in 10, 20 or more years time? In the case of modern mechanical switches, they are almost always not repairable and finding a replacement will probably be even harder then. As for the electronics, complete unit replacement, if available, is most likely to be needed, since the original solid state components would be obsolete by then. On the positive side, I would expect solid state relays to be around for many more years.
Cheers,
Darrell
[ Editor's Note:
[
[ Please be aware that solid state devices have their own peculiar
[ failure modes. Lamp Dimmers which are permanently wired into
[ houses must (amongst other things) have a mechanical "cut-off"
[ to be UL listed. Remotely operated motors for things like Air
[ Conditioning must always have a mechanical cut-off switch near
[ (and in visual range of) the unit to meet electrical code.
[ There's a lesson here for people who work around the drive motors
[ of band and dance-hall organs, etc: If its plugged in, assume
[ it can start "automatically" and keep your appendages away from
[ the soon-to-be-moving-parts!!!
[
[ I know one collector who runs his entire collection off an
[ electrical panel (circuit breaker panel) with a huge mechanical
[ relay which can be used to shut off everything in the entire
[ building, except for the house lights and air conditioning. There's
[ no chance of something turning itself on at night, or some piece
[ of weird insulation turning into an electrical heating device
[ since there's no power. |
(Message sent Tue 20 Aug 1996, 15:55:00 GMT, from time zone GMT-0600.) |
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