Re: Alternators and the care and feeding thereof

[quk@isham-research.demon.co.uk (Phil Payne)]

In message <5dacd3d6.36dd8d6f@aol.com> FBFISH@aol.com writes:

> Anyone out there have any idea what I am talking about?

I was a humble cable and wire engineer when we were approached by a
company called Lucas to produce a winding wire that would withstand
the more extreme demands made upon it when used in a new-fangled
gadget they were developing called an 'alternator'.

One glance at their specifications (areal density of current, operating
temperatures, duty cycles, product lifetime, etc.) convinced us that
oil-based varnishes - until then absolutely standard in the winding wire
industry - would _never_ meet the requirements.  We had to throw _all_
of our technology away - all the chemistry, the floating die application
technique, the lubrication, the way lubrication was applied -
everything.

The new enamel was water-based and roller-applied.  It took the best
part of a year - after the chemistry was sorted out - to get the roller
application system and the oven working.  Ever seen an oven seventy feet
high, ten feet wide, and just over an inch deep?  Those
wonderfully-shaped stator coils are wound circular - they're coerced
into those shapes with a leather mallet.  During the process, the coils
move gently against themselves - if they're not lubricated, the
insulation rips off.  We tried all the oils and greases in the
catalogues - we finally settled on a refined form of beeswax.  The
spreader was another problem altogether - the beeswax was dissolved in
alcohol (I think the first prototype actually used methylated spirits!)
and spread across the wire as it left the last (cooling) loop on the
'head'.  We tried foam rubber, sponge, reconstituted industrial fibre
blocks - everything.

Success was finally achieved using a 3" section of the chief chemist's
leather belt, wound in a Mother's Pride loaf wrapper in which a tiny
slit was cut.  The plastic kept the alcohol from evaporating too
quickly.  The chief chemist kept his trousers up with a sample of the
successful wire for the rest of the day.

There's actually more wire in an alternator than in a dynamo - about 2
1/2 times as much.  So to equal the dynamo production rate, the winding
machines had to run almost three times as fast.  It's very difficult to
pull wire off a spool at high and erratic speeds - the spool has huge
inertia - so we had to develop a delivery system that was almost
inertia-free.  The solution was a large double drum - external diameter
just over two feet, and internal diameter about a foot and a half.
About four feet high. The wire was dropped into this drum between the
walls in loose coils.  Didn't solve all the problems, because it 'winds
up' as it's taken out.  So the coils were pre-biased by passing them
over rollers and dropping them into a gently rotating drum.  The
platform on which the drum sat was driven round by an electric motor
controlled by a Variac (sp?) transformer.

All of this was in the days before personal computers or even pocket
calculators.  Despite having no formal qualifications, I got the job
because I solved a nasty little surface tension problem during the
interview using my slide rule - and then proceeded to demonstrate to the
chief chemist that my slide rule was markedly superior to his for
solving that type of problem.  Fewer end switches - a set of pi-factored
scales on the back.

We used to walk around the plant with clipboards and slide rules.  Every
now and then, you'd come across two or three of us sitting on a cracked
and stained industrial concrete floor in front of some machine -
tachometers and micrometers scattered around, and a slide rule in every
hand.

It still annoys me, on behalf of the Lucas engineers, that Lucas ever
got the 'Prince of Darkness' reputation.  They were damn good guys,
but they oversold their sales force on their over-engineering.  As a
result, massive numbers of British (and other) cars were built with
under-specified Lucas equipment - which, of course, proceeded to fail.

Knowing the old (1960s) product range, every time I look in the engine
bay of a British 1960s classic I think - if _only_ they'd fitted the
proper (i.e., two steps up the range) alternator.

--
 Phil Payne
 Phone: 0385 302803   Fax: 01536 723021
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