[TR] alternator conversion in a tr3

[Dave]

 In both these situations a bi-color LED will be handy.  The two lead variety have two different color LED dies connected back-to-back so that reversing polarity will change color.  This way you can have a turn signal indicator that will flash red for Right and green for Left.

http://tinyurl.com/p9s5dex

 

Dave Massey


 

 

-----Original Message-----
From: Randall <TR3driver at ca.rr.com>
Subject: Re: [TR] alternator conversion in a tr3


> It is a long story, (don't ask it hurts,) but in reality a 
> LED bulb will
not 
> complete the charging circuit at low engine revs under 2000- 
>
2500rpm. Fact.

An easy solution for that problem (sorry, Dixie) is to add a
resistor in parallel with the lamp.  The resistor is a good idea anyway
(IMO)
in case the bulb ever burns out (or fails to make contact).  I had one on my
TR3A with alternator conversion, simply soldered
to the back of the bulb holder
but sticking out a bit to keep the heat away from the plastic.

Also, some
alternators (the ones that can be used in a "one wire" configuration) will not
exhibit the above problem.

However, there is another potential problem with
the ignition warning lamp; which is that it can see substantial reverse
voltage.
Not all LEDs can withstand that much reverse voltage without damage. 
So a series diode may also be required.  The diode may also be
needed if you
have an electronic ignition that has it's own power feed, like an MSD
6A.

There are also some TRs where the turn indicator lamp operates with both
polarities (eg 69 TR6).  They will also need some
modification to use an LED
for the indicator (in addition to the mods to use LEDs as turn signals).

--
Randall  



 
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