Bicone Switches
By Spencer Chase
Well it seems there is more than one opinion on what constitutes good and bad old junk. I think that the bicone switches are great. Most people don't know that they exist because they are only starting to fail now after 70 years of neglected service. (I have replaced numerous modern switches after only a couple years of use.) They may be crude and badly engineered by todays standards but they last and are repairable. I also like the switches in my land rover which can be disassembled cleaned and lubed using only a tire iron and some bear grease in less time than it takes to pick up your cellular phone and call AAA, but some people prefer the modern easy approach. They are snap acting wiping switches and do as well to suppress arcing as modern switches. When they fail it is usually a broken spring which can be easily fixed or worn contacts which can usually be dressed. Some of the springs are "snake swallowing its tail" which are inpossible to make without spring winding equiptment but others are just short springs looped together endloop to endloop. Springs like these can be found in old typewriters or in places that repair them. The loop to loop seems to be a fine replacemnet for the other type. Make sure to resurface the bicone and lube with an non conductive (eg. silicone) grease. When the contacts fail it probably means that the switch has had a lot of use, or that the load is too high. Before putting it back in service check the motor load and preferably switch the current with an ssr or other relay. Even just barely there contacts will opperate an ssr. You could even replace the spring contacts with solid metal to switch milliamps.
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(Message sent Wed 21 Aug 1996, 18:14:24 GMT, from time zone GMT-0700.) |
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