Alternator

[rob-53uk]

Hi All
the alternator on my roadster decided its had enough. the alternator (lucas)was from a marina fitted to a ford crossflow. the loom is from a marina. i have purchased another alternator from my local scrappy however this has come from an escort. My question is what is the single black and purple wire for coming off the back of the marina alernator??. the alternator works fine and it fits the marina bracket

[amalgamated users from prior forum]

Re: Alternator

Message originally posted by: Don
Ok I have just been through every wiring diagram for every Marina variant from introduction to 1976, in the official Leyland manual. None of them show a black and purple wire from the alternator. Yours may be a later model.

Some Lucas alternators had a sensor wire that ran to the positive terminal of the battery to sense the battery voltage to control the charging. Later a genius in Lucas realised that there was already a big fat brown wire that actually charged the battery, which ran to the positive terminal so a separate sensor wire was not needed. These alternators were dubbed internally sensed. The sensor wire according to the diagrams was brown with a purple trace. Some alternators also had a separate earth wire, mine is yellow!

The brown/yellow wire runs to the warning lamp. If the warning light blows, then the alternator wont start charging because it relies on the current through the warning bulb to energise the field (rotor) coils, at low rpm. Hence the bulbs was sometimes of surprisingly high wattage or had a parallel resistor.

Later Lucas alternators as fitted to say Metros are interchangeable with the earlier ones and are much more reliable. Bosch alternators are even better.

Hope this helps, Don

[rob-53uk]

Re: Alternator

Thanks Don I have looked at the wiring diagrams in the haynes manual and like you have found nothing but the wire was fitted on the alternator to a terminal that was live when the engine was running but no current when switched off. O well the new alternator works without the wire connected so I'll not worry to much
Bob

[neilryland]

Re: Alternator

This might well be the output drive for a tacho on a diesel. if it works without it connected then don't worry about it.

[dogoncrazy]

Re: Alternator

Bob
I also went through all my notes from the time I built mine - nowhere could I find the cable colour you refered too.

[amalgamated users from prior forum]

Re: Alternator

Message originally posted by: Sue Roedel (MOC Editor)
I can't remember the colour of mine but I have a wire on my alternator not attached to anything.

[amalgamated users from prior forum]

Re: Alternator

Message originally posted by: Sir bodge alot
my theory would be: If it aint broke , don't fix it, but ifit is broke and the fix works, forget about the little bits that are left! its abit like finding one bolt left at the end of a self re build. if nothing has fallen of then hide it before anyone else sees.

[paul]

Re: Alternator

I don’t know about Escorts but the Sierra Alternator has a Blue wire for the charging light and a Blue/White wire that connects directly to the Electric Choke. Could it be connected to something on the Crossflow?
Paul

[neilryland]

Re: Alternator

I've got hold of a brand new Lucas LR122 alternator, tried to use it but couldn't get it to charge at all. Seems to have two extra connection points that I couldn't find out what to do with. Only info I could find on the "Interweb" thingy was that this application required an external battery temperature sensor and the LR122 was intended for agricultural applications. Tried wiring these up in various ways to no avail.

So filed it away back in the shed and fitted a Pug 205 55a/h jobby (£10 from a scrappers). Now switch everything on lights / heater / horn / cooling fan / ignition system / injection system / brake lights / hazards and it still holds 14.4v at 1200 rpm. Much better than the old Lucas 16ACR I had on before.

[rob-53uk]

Re: Alternator

Hi all
I have attached a photo of the alternator the rouge wire was fitted to the top terminal ( above the three pin connector)
Bob

[b_caswell]

Re: Alternator

Could be the alternator was off a car that had towing twin electrics, the extra wire would have gone to a secodary relay to charge the trailer battery.

[rob-53uk]

Re: Alternator

now theres a thought Ben. I will check it out
Bob

[Dane_Rescueman]

Re: Alternator

Bob, I'm just refurbishing my Lucas alternator on my car. On mine, the single spade connector was connected to a suppressor which had a little bolt through the LH (in your pic) bolt hole.

[philcoyle]

Re: Alternator

Bob, there is a good tech page for alternators on qxcomponents.co.uk, and you can find out about your spare terminal.

[Dane_Rescueman]

Re: Alternator

Bob, i have just cleaned up my Lucas alternator and mine has a suppressor attached to that single spade connector. The suppressor itself is mounted with a little bolt at the hole on the left of your picture. Hope this helps!