-=> Jay Emrie said to Greg Mayman
 -=> about "{at}%^{at}#$%^ VEROBOARD" on 03-31-04  10:08.....

 JE> I am a mite puzzled by this. In the 50s most cars here used a flasher
 JE> that had a coil around one arm - bimetallic I believe (of a pair that

All the flashers I remember did _indeed_ have a coil around one
arm, but this was an electromagetic part that gave the flasher
hysteresis, and also closed a second contact that operated the
indicator light only when the rated current flowed through the
coil.

The main switching was by the stretching of a piece of thin wire
when the current passed through it.

If there really were any that used a bimetalic element, I never
saw them.

From my experience with bimetal time delay relays, I cannot
believe that they could ever be made to work fast enough for a
turn indicator flasher.

Cooling down is the problem, unless they worked at near red heat,
or were cooled by a forced draught.

OTOH the ones I saw with a piece of resistance wire that
stretched when it was heated had very little thermal mass. They
would cycle at about 4-5 times a second unless the current
through the electromagnet section was sufficient to hold them
operated a bit longer, in which case they slowed down to the
required 1-2 flashes a second.

   ,-./\
  /     \ From Greg Mayman, in beautiful Adelaide, South Australia
  \_,-*_/    "Queen City of The South"    34:55 S  138:36 E
       v

... I'm not sure if life is trying to pass me by, or run me over!
___ Blue Wave/386 v2.30

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