[M] Alterpower alternator charging control switch

[Jemison Richard]

I agree the alternator output is very low when the battery is charged but
the stator coils are still charged (and therefore exerting a magnetic field)
and there is still a mechanical loss associated with spinning the
alternator.   I don't know that you can prove or disprove this theory on the
electrical basis of the alternators parameters alone completely discounting
the mechanical losses.  All I can tell you is that this has been a pretty
well established and observed loss on dynomometers with engines running at
speeds above 5000 rpm.   Alternator on the engine (X -5 hp).  Stop - pull
the alternator - rerun the test ( X output!).  Seems pretty simple.  For
myself - I don't really care WHY the alternators sucking the power.  If I
get down to where 5 hp makes the difference - the alternator's gone!

rick

> -----Original Message-----
> From:	KD6JDJ at aol.com [SMTP:KD6JDJ at aol.com]
> Sent:	Friday, March 12, 1999 2:20 AM
> To:	diy_efi at efi332.eng.ohio-state.edu
> Subject:	Re: [M] Alterpower alternator charging control switch
> 
>   I thought that this discussion started out as one that considers how
> much
> power could be unloaded from an engine if the alternator was to be
> disabled.
>   I wanted to point out that -- when a battery is charged up , the voltage
> regulator cuts off the current to the stator and the rotor spins with
> little
> resistance. So, little power is consumed by an alternator its regulator
> senses
> 14.2 volts. And when the battery cells get up to 12VDC the alternator
> needs to
> supply very little energy to the battery. 
>   The rest of the car may have need for power from the alternator.
>   If we consider that the alternator is 75% efficient , it will consume
> 746
> watts (1 hp) when it delivers 560 watts. That is about 40 amps at14 volts.
> 
>   I thought that it would be clear that the 5 hp claim is based on
> something
> that most cars ( with operating voltage regulators ) dont encounter.
>   Maybe the satisfied users of the alternator disconnector are
> professional
> racers , where every little bit counts.
> 
>   While I'm at it --- 99% of todays automotive alternators are 3 phase AC
> ,
> with 6 diodes in a full wave bridge. It is impressive how little ripple
> results .
> 
> 
>    Jerry
> 
>   
> 
>