While cruising today I happened to find this intriguing email;
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Subject:Re: Gee kids! Here's an experiment you can try at home.
Date:Mon, 05 Oct 1998 06:23:29 GMT
From:teba@execpc.com
Newsgroups:sci.econ,sci.environment,sci.energy,sci.space.policy
In article <36181E18.A9ACCD50@home.com>,
John Wilson <wilsonjohn@home.com> wrote:
> Paul Dietz wrote:
> >
> > > To make a Tesla turbine work at good efficiency, it needs to
turn extremely high rpm, something like 100,000rpm IIRC. This is just
not
> > > practical for a generator. 60Hz is 3600 cycles per minute. A
two-pole generator turning 3600rpm is the fastest a generator can spin
and
> > > produce 60Hz power. Conventional steam turbines work fine at
3600rpm, but a Tesla turbine would need an exotic, and probably
high-maintenance,
> > > gearbox to reduce the speed to usable levels for power
generation. As I understand it, this is the main reason the Tesla
turbine has not made
> > > much of an impact.
Wrong,
The Tesla turbine for 3,600rpm contained a runner of only 48" diameter.
Tesla's 60" diameter turbine runner operated at the four pole speed of
1,750rpm.
18" runner = 9,000rpm
9 3/4" = 18,000rpm
We do have documentation of Aerojet Inc. building a Tesla type disc
pump that operated at 140,000 rpm with a head rise of 24,000 Ft @
15GPM, but
its runner was only 1" diameter.
Recent tests indicate that a properly constructed Tesla turbine,
operating in the direct combustion mode, can achieve similar
efficiency to that possible with the "Capstone" micro turbine but at
much lower speed.
Tesla did use a high speed alternator with a turbine using a 6"
diameter runner. This turbine was intended for lighting steam
locomotive headlamps where high frequency was not a problem. The
18,000 rpm, 9 3/4" test stand, operated through a gearbox to a 3,600
rpm alternator.
Tesla Engine Builders Association (TEBA)
http://www.execpc.com/~teba
=====================
I cannot imagine a pump that could push water 24,000 feet or I being
stupid and misreading this thing?? Here is an additional post of use;
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Subject:Re: Gee kids! Here's an experiment you can try at home. Date:6
Oct 1998 04:01:02 GMT
From:Bloody Viking <nospam@tekka.wwa.com>
Newsgroups:sci.econ,sci.environment,sci.energy,sci.space.policy,sci.physics
In sci.environment John Wilson <wilsonjohn@home.com> wrote:
: To make a Tesla turbine work at good efficiency, it needs to turn
extremely high rpm, something like 100,000rpm IIRC. This is just not
: practical for a generator. 60Hz is 3600 cycles per minute. A
two-pole generator turning 3600rpm is the fastest a generator can spin
and
: produce 60Hz power. Conventional steam turbines work fine at
3600rpm, but a Tesla turbine would need an exotic, and probably
high-maintenance,
: gearbox to reduce the speed to usable levels for power generation.
As I understand it, this is the main reason the Tesla turbine has not
made
: much of an impact.
Shipboard turbines run faster than the 3600 RPM for the generators,
becuse they are smaller units than commercial turbines. The 44
kilohorse main engine turbine ran at 7,000 RPM with the proverbial
pedal to the metal.
That 100,000 RPM is comparable to a dentist drill! Now, what size was
the Tesla turbine? The 11,000 RPM ship generators were 1.5 megawatts,
and the
main engine with it's 44 kilohorses. Gas turbines can rack up some
good RPMs too. A turbocharger in a car runs at 100,000 RPM at max-out.
If you notice, there's a bit of a correlation with size and speed.
Gearboxes, properly designed with the motor oil system, can be fairly
low maintenance, except for purifying the oil on a regular basis like
a ship.
: In this connection, note that modern fossil-fueled boilers operate
with steam pressures of 2400psi or more with high levels of superheat,
or at
: about 3600psi with supercritical steam. We're talking about steam
lines that are red hot inside their lagging. Nuclear systems, because
of the
: fuel temperature limitations, operate with steam pressure around
1050psi and saturated steam. These steam conditions were
state-of-the-art for
: fossil-fueled generation about 1910.
Those are some NASTY pressures. The Navy's max steam pressure is
"only" 1200 psi at 900F for fossil-driven plants, and that's pushing
your luck.
Ever work on that kind of junk? That 900F steam will cause a
broomstick to smoulder if it leaks. A pinhole leak resulting in an
invisable jet can cut it in half - or cut your arm off like a laser,
cauterising the cut! In the
engineroom, we had fun lighting cigarettes by finding a small
uninsulated patch of the steam input pipe on the generators.
===================
Subject:Re: Gee kids! Here's an experiment you can try at home. Date:6
Oct 1998 04:07:56 GMT
From:Bloody Viking <nospam@tekka.wwa.com>
Newsgroups:sci.econ,sci.environment,sci.energy,sci.space.policy,sci.physics
In sci.environment Paul Dietz <dietz@interaccess.com> wrote:
: I don't know anything about a "Tesla turbine", but the better thing
to do with a very high speed turbine would be
: to drive a high frequency generator, then electronically convert it
down to 60 Hz. No gearing.
That would work. You take the high frequency output, rectify it to DC
(with capacitor) and feed it into an inverter. The 60 HZ output is
independant of alternator speed. The inverter onboard a car already
does this in a way. With the car case, the alternator's AC is variable
in frequency, to make things more fun.
: This kind of arrangement is being used with microturbines. The
Capstone Microturbine, for example, rotates at 96,000 rpm.
: See http://www.capstoneturbine.com/index.html
Yep, it will work. :)
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