Lotus Elan and Lotus Elan Plus 2 Forums

Hi folks

I have a 1965 negative earth elan with a single wire alternator. I am reading about 3.5 amp electrial load with all systems switched off. After doing some checking I noticed that the load seemed to be going through the wire to the single wire alternator.

I disconnected the wire and could no longer measure any amperage. If I check the voltage from the fitting on the wire to the frame measure 12 + volts. If I do the same to the terminal on the alternator I also measure 12 volts.

I am not sure why the terminal on the alternator is grounded and I assume that this is the cause of the electrical leak.

Does anyone have any suggestions?

robb

Hi Robb,
Is this the same problem you had 5 years ago......

lotus-electrical-f38/voltage-leak-alternator-t17403.html

The problem was a bad voltage regulator- been replaced and am good to go

Oldelanman,

If I recall correctly, when I first put in the alternator I was using the old voltage regulator as a junction box since it was no longer needed ( with the internal regulator within the alternator) - When I removed that the issue went away.

Now it is back again. I am thinking it has to be some sort of short in the alternator.

R

just as a follow up:
- 3amps to alternator when everything is shut down
+ 28 amps when engine is running.

R

It's clear that your alternator has broken, nothing else is involved. It's probable that it isn't regulating properly either so you are risking the battery if you continue using it.

One diode in the rectifier has probably failed, a fairly easy fix.

Another vote for diode fault.

Thanks guys,

I will take it down and have it checked.

Ok this is where I get to admit that I do not know anything and do not have any memory left!

I completely forgot that two years ago a local auto electrician did replace the voltage regulator in nipon denso alternator

This has now failed again. So I think maybe I am doing something wrong that is causing the failure.

In addition to the single wire there are three other poles on the alternator. Since this is supposedly a one wire are they even active? how can I tell? I do not have any of them connected - could this have anything to do with the repeated failures?

That doesn't sound right. I can't work out what you mean there.

Here is the Lucas Fault Finding manual
www.atcc.org.nz/tcc/LucasFault.pdf?


See also some recent discussion about Alternators:

lotus-electrical-f38/new-alternator-not-charging-batt-light-stays-t28734.html

lotus-electrical-f38/ignition-light-not-t28756.html

Thanks Bill

Sorry for the confusion Hopefully the picture uploads properly.

the only connection that I am using is the one labeled B in the attached photo.
My car is not fitted with neither an ingnition light nor alternator light.


Robb

robb4100 wrote:Thanks Bill

Sorry for the confusion Hopefully the picture uploads properly.

the only connection that I am using is the one labeled B in the attached photo.
My car is not fitted with neither an ingnition light nor alternator light.


Robb

Interesting. I have a similar alternator, furnished by Gustafson Machine. It's origins are a 91 Suzuki Samurai. The harness for my alternator had the two parallel spade terminals in the circular socket jumpered to a 18gauge wire lead that connected to the old Lucas control box. The control box now functions as a terminal strip for the electrical system. I will see if I can scan the instruction sheet and post it.

Regards,
Dan

All I can suggest at this stage is read off any manufacturer name & type codes and use Google to search for instruction sheets or manuals and repair guides.

Perhaps Dan's one will do the trick.

But as said above the most likely thing is a failure of the diode pack inside or the internal voltage regulator.

My attitude on such alternator failures is that if a pack fails, the rest of the alternator could probably due with a good clean-up and service too, so I might as well change it for a refurbished/rebuilt one & let the specialists sort it out with all the right tools, parts and test gear.

Here's a page I found with alternators with the same pinout as yours
http://westfield-world.com/daihatsu_alternator.html
but there are two conflicting wiring diagrams. !!!







Reading other stuff it would appear that if you look carefully inside that 3 pin socket you should see that one pin is labeled IG (for ignition switch) and another labelled L (for light) and the third may be labelled D for dummy.

http://www.vansairforce.com/community/s ... php?t=5741





None of which account for the problem in your original post. Which still looks as if something has failed inside.

Another interesting page:

http://diagramandwiring.blogspot.co.uk/ ... -work.html



Still more good stuff.

http://alternatorparts.com/FAQ.htm