[Healeys] (no subject)alternator

John Harper ah at jharper.demon.co.uk
Wed Aug 20 13:00:18 MDT 2008


Eric

When a generator (dynamo) is connected to the battery because the speed 
is sufficient to close the cut out in the control box, or an alternator 
is running at sufficient speed, this source of power is directly 
connected to the battery and also to any load that is switched on. 
Therefore one has a three way connection where, depending on whether the 
load is greater or less than the generator or alternator output, current 
will flow out or into the battery. Some owner fit an ammeter to watch 
this. Part or all of the load can be taken from the generator or 
alternator. In fact as somebody said recently it is possible to run a 
car fitted with a generator with the battery disconnected so long as the 
engine revs are kept high enough. Obviously once the revs drop there 
will be insufficient power to keep the ignition alive and you will not 
be able to restart without reconnecting the battery..

The reason for this long explanation is to let you know that your 
statement that "All electrical consumers in a car are fed by the 
battery" is not entirely true. However 'connected' to the battery is a 
valid statement

What I was trying to say in my previous email is that a heavier cable 
should be fitted to match the output of the alternator. This is because 
an alternator is capable of charging the battery at a suitably high 
current AND run all the lights and accessories.

Best regards
>
>John, I don't know what you mean. Maybe because English is not my native
>tongue.
>
>All electrical consumers in a car are fed by the battery. I've seen no
>consumer fed by the alternator directly. Of course the battery is fed by the
>alternator, so the alternator feeds all consumers indirectly via the
>battery. I'm not sure about modern cars, but I know for quite sure that this
>is the way the electrical charging system works in our AHs.
>
>As you say, if you replace the original cable between alternator and battery
>(after upgrading to a 50 amp alternator) with a 50 amp cable, everything is
>fine. Maybe this is what you said and I didn't get it right. At least this
>is what I wanted to say.
>
>Best regards

-- 
John Harper


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