Given the endless discussions on this topic, thought it would be useful to
remind myself and any others who are interested in the major differences
between alternators and generators
In a gen. the heat generated is in the rotating armature that is on the inside
of the enclosure and this is why cooling is important/difficult and the fan on
the pulley provides this through the enclosure. The brushes on a gen work hard
and switch full current several times per rev. hence the wear and sparking. Gen
usually has an oilite bearing at the rear that also wears. This is a critical
component as wear (dry no oil) could eventually lead to scraping of the
armature on the field poles and throwing of lead at comm. Take care of your
brushes, bronze bush and bearings and you will have a reliable gen.
An alt. is inverted with the main winding on the outside (easier to cool hence
more output) and the field on the inside; hence the shape - larger diameter
and shorter. No mechanical commutator switching needed as this is done by
diodes. Slip ring brushes feed low dc amps to the internal rotating field -
that last almost forever. Alt usually have more reliable front and rear rotor
bearings and less rotational weight as the main windings are on the stator and
thus more mechanically robust than a gen.
The discussions here also confuse me about the amps needed for our cars. I am
with Chris on this one and wonder why you would need an 80 amp alt ?? !! Unless
you run an extra 2 spots for long periods you likely don?t need the hi output
of an alternator rather the mechanical reliability and the improvement of
eliminating the mechanical regulator.
Lets say headlights at 55W each; 5 amps for ignition and auxiliaries; 3 amps
for side lights (convert these plus brake lights to LED?s to lighten your
load); blower at 3 amps; wiper at 5 amps; OD 1 amp as worst case continuous.
This gives a total of around 26 amps full house driving at night in the Winter
and raining ! Intermittent loads are horn, brake lights, indicators. etc.
No doubt one day will convert to an alt but it would likely be to eliminate the
awful cheap non adjustable regulator that I had to purchase after my 50 year
old Lucas one failed.
rg
From: Chris Dimmock
Sent: Monday, May 1, 2017 6:42 AM
To: Simon Lachlan
Cc: Healey List
Subject: Re: [Healeys] Dynalite or which alternator to C42 Generator
The funniest thing I find about the "alternator inside a generator" conversions
is the bloody pulley. It might look like a generator body - but you have to run
a tiny pulley, because it needs a bucket load of revs to generate didly squat,
more than a generator.
Any good Lucas generator runs a Larger pulley - because it generates enough
amps and stuff at low revs. Seriously men. Who revs their car past 5,000 rpm on
the road?
I run a C42 with a bigger DWR Pulley.
That means I'm slowing down the old Lucas C42. Because it already generates
enough power.
Ok. I'm not running a 1,000 watt sound system or 4 IPods, and a grille full of
spotlights. FFS - it's a Healey!!
So if you run one of these alternator inside a generator silly things, it's a
joke. You've got a fake, compromised alternator. Immediately identified by the
pulley. An alternator needs air for cooling. A generator casing doesn't provide
that.
Run one or the other. Generator or alternator. I've got no issue if you run an
alternator. Run a good, sensible, reliable one.
Nearly as stupid as putting a disc brake inside a brake drum. Same issue.
Innovative- but it doesn't work unless all you do is drive to a coffee shop.
Simon. Just get a C42 and return the core when you get back.
Best Chris
Being Grumpy about modern shit.
Sent from my iPhone
On 1 May 2017, at 3:54 am, Simon Lachlan <simon.lachlan at homecall.co.uk>
wrote:
My nephew?s generator issues may resolve themselves soon. May??.
We may look at replacing the C42 in his BJ8 with an alternator, one of the
generator lookalikes.
Dynalite is one of the names I?ve come across, as sold by Holden?s. The Usual
Suspects don?t seem to give their lookalikes their brand names.
Anyhow, I know this topic came up a few months back, but I wasn?t interested
then! So:-
Does anyone have experience of these things?
Is any brand better than another??
Etcetc.
Holden?s claim 45amps for theirs. AHSpares claim 50amps. A BJ8?s C42
generator kicks out 30amps max. It seems that one does need the BIG fuse in the
Dummy Control Box. When I put in my alternator, a Lucas ACR, I put in an extra
cable to carry the extra amps??.apparently if the alternator is really belting
out the amps, the old wiring is a bit marginal.
Any other thoughts?
Kind advice to the effect that putting more modern electrics in our old
bangers is streng verboten is unnecessary at this time.
Thanks,
Simon
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