Lotus Elan

Capacitor on the clock hot lead

PostPost by: Bud English » Sat Oct 28, 2017 5:50 pm

I'm getting things sorted for putting my fascia back together so I got out all the instruments to clean them up and change the pitted bezels. In doing that I found a 1 micro farad, 150V DC capacitor across the hot lead of the clock. Strange place to put it, but I'm assuming it's for radio noise suppression. It doesn't show in the wiring diagrams, at least that I can find. Anyone have any knowledge on it's purpose?
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PostPost by: bob_rich » Mon Oct 30, 2017 9:43 am

Hi Bud.

It has been fitted I guess for radio suppression . If you have the Kienzle clock these are basically clockwork mechanisms with an electric rewinder that takes a big pulse of current (~1A). When the current is turned off as the
clock rewinds interrupting this current this results ( in radio noise terms) a potentially large interfering pulse around once a minute. so maybe the capacitor was fitted to try and suppres a click pulse on the radio. Should not be any
problem to keep it in circuit.

hope this helps best of luck


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PostPost by: Chancer » Mon Oct 30, 2017 11:48 am

That definitely was the advice back in the day for non RPM proportional random radio interference, I fitted one to the clock in my Stag.
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PostPost by: Bud English » Mon Oct 30, 2017 3:30 pm

Thanks guys. That makes sense after reading a thread on how the clock works, here. http://www.oldclassiccar.co.uk/forum/ph ... hp?t=10488, as posted by draenog here on this forum.

In searching, I never found a reference to the capacitor, but from your replies it sounds like they were added after the fact.

I'm not sure an electrolytic capacitor would still be viable after sitting unused as long as that one has. I'll leave it though and if the noise presents itself it will be fairly easy to swap out. Thanks again.
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