| Jensen
Model #95G Turbine Power Plant Engine
Prototype |
USA - Manufacture date:
2005
Bore = N/A, Stroke
= N/A
", Flywheel diameter
=2.5"
Style: Prototype , Impulse
Rotor
|
Dimensions: 14" length x 12" width
x 10" height
(includes base) |
|
|
|
Prototype Jensen 95G Turbines |
|
Every once in a while you get to be a part
of something you can take pride in. This
is very much the case with the Jensen
model 95G Turbine Power Plant project. Recently
documented information from a very rare
tape recording confirmed that a Jensen
steam
turbine has been discussed off and on
since 1932. I'm pleased to say that
I was lucky enough to be a part of the project that finally
brought this long awaited Jensen model to reality. The project took 2 years
of discussions, planning, design, redesign,
testing, more testing and finally, after
far too long, approval and introduction
to the Jensen product line. Throw in a few disappointments,
several roadblocks and some serious
sweat and you'll get a
sense of the roller coaster ride
this now mighty little power plant took
us through. |
|
The idea of a Jensen turbine is
certainly not a new one. The idea has
been reborn a number of times over the
past 70 plus years, but it was always rejected
as not being visual enough to demonstrate
the system effectively. Let's face it...
a spinning shaft sticking out of a enclosed
rotor casing is about as entertaining
as watching paint dry.
That was all before
Karsten,
a young German turbine maker, came to
my attention a few years back. Several
of Karsten's earliest designs can be
seen on this site, along with a bit of
the our history. After re-establishing a
once lost relationship, I mentioned
that I'd like to explore the idea of
a Jensen turbine. As we traded ideas
via email, we began to come up with what
seemed to be a viable solution to the
boredom factor and I began modeling
the project in 3D to see if what we
envisioned would actually work
|
 |
Early 3D Design
Rendering |
|
|
 |
View of the 95G Gear Train |
|
After a couple
of false starts and
trip or two back to the drawing board,
Karsten took the basic design and worked
his own special magic to tweak the idea
closer to a working design. He shipped
me a couple working prototypes for testing
but it soon became obvious that there were serious
issues that were very much in need of solutions.
A steam
turbine requires several
things to work properly. The steam supply needs
to be constant, at a usable pressure
and it has to be of high velocity. Then
there is the basic nature of a turbine
which had be dealt with. A turbine rotor
turns
at very high rotational speeds, but it
delivers very little useable output
torque.
In order to harness the energy a turbine
produces, the low torque rotational
force has to be reduced
through a transmission system to increase the
torque to a more usable level.
|
Testing continued and we
began to find solutions
to each problem, one by
one. Some internal redesign
ensued, along with adjustments
to the transmission reduction
system. A second round of
prototype turbines arrived
from Germany and the
first of three was mated
to a Jensen electrically
heated boiler, as testing
began anew.
It
was immediately obvious
that we were getting closer
to the right track. We had
plenty of back pressure
in the system to maintain
a steady steam supply. We
had the steam velocity up
to a level that was
producing amazing RPM's and
the output though the gear
train was in the proper
range to theoretically power
a Jensen DC generator. Still,
the combination just
didn't quite seem to have
the "WOW Factor"
we were seeking.
|
 |
Early view of the 95G Turbine
driving a Jensen
15E DC Generator |
|
I decided it was time for
some outsider input, so
I contacted a small but
very loyal group of Jensen
aficionados and shared
photos with them, asking
them to maintain confidentiality
until the project either came to an end, or
it was accepted by
Jensen. This proved to be
a very good idea , but it
also added another
level of pressure to get
the project right.
Karsten
had tweaked the design about
as close to the optimum as his
machine tools would take
us. The rest fell to me
to find a balance between
performance, appearance
and that elusive WOW factor.
I tried a number of variants,
making progress in small fits and
starts, toward what I thought
was a final version.
However, the collectors'
feedback soon told me I
was not quite as close as
I had hoped. They heartily
agreed with the visual design
of the turbine motor, but
the small Jensen 15E DC
generator was certainly
not winning any hearts or
minds. They indicated that
while they were totally
pumped over the turbine
concept, "the gotta
have it" ingredient
was missing. They unanimously
agreed that they would prefer
to see the more visually
interesting
Jensen model 15 AC generator
used in the final version.
So.... it was back
to the drawing board again,
with a whole new group
of roadblocks
to negotiate.
The
problem was that the turbine
worked fine with the lighter
load of the DC generator,
but the AC version had a
much stronger magnetic field
which gained in resistance
as it turned faster. The
turbine could turn the AC
generator but it was too
slow to light the lamp post
above a dim glowing flicker.
I must have made up 30 or
40 different combinations
of pulley ratios, on my recently
acquired lathe, but things
were not improving to any
great extent. It was frustrating
to be so close, yet so far
away from what was a potentially successful
configuration. The collectors
were enthusiastic about
the addition of the Model
15 AC Generator and were
getting excited by the "look"
of the display. The "gotta
have it" thing was
steadily creeping into the
design, as the crew provided
feedback on each new batch
of photos.
|
 |
Flywheel and Model 15 AC Generator |
|
Have you ever had a "EUREKA!!"
moment? As sometimes
happens, this
one came while I
was sleeping
and it was enough
to wake me up.
It dawned on
me that Karsten
had left an
exposed stub
on the end of
the final stage
output shaft
for a small,
very narrow
pulley. By extending
this stub, I
could fit a
Jensen flywheel
which would
have a nice
3 inch diameter
and a PTO groove
already in place.
At about 3:30
in the morning,
I cranked up
the lathe, chucked
some brass and
cut a new shaft
extension. I
pressed fitted
it onto
the exposed
stub and added
the flywheel.
After installing
a drive spring
belt and waiting
for the boiler
to heat up,
I held my breath
and opened the
throttle valve.
The motor tried
to run but wouldn't
start on its
own and it slowed
down very quickly.
I scratched
my head a bit
and gave the
little turbine
the evil eye.
|
While I was giving the machine
the hairy eyeball,
it was steadily
building a full
head of steam.
This was announced
by a plume suddenly
rising from
the relief valve.
I reached for
the throttle,
gave it a twist
and was rewarded
by the sweetest
sound I could
have asked for
at that moment.
The little turbine
began to spool
up with a unique
whine
and continued
to increase
in speed until
the lamp post
was shining
brightly. To
my delight,
it maintained
enough speed
to keep the
bulb brightly
lit through
an entire
boiler full
of water. A
few more test
runs to make
sure this was
no fluke and
I was off to
bed again just
as the sun began
to come up.
The
project was
submitted to
Jensen as somewhat
of a "Fait
Accompli".
They knew I
was working
on some sort
of prototype, but
I suspect they
were not giving
it much hope
or encouragement.
After all, the
project had
been discussed any
number of times
for over 70
years with no
results. It
took a few weeks
to convince
Mr. Jensen to
test the thing,
but when he
finally got
around to it,
he was an immediate
convert. The
Jensen model
95G was introduced
in October of
2005 and is
now
a very successful
product... and
the first totally
new Jensen design
since the 1960's.
The first 25 of
the 95G's
were numbered,
dated and signed
by Tom Jensen
Jr. as special
collector pieces.
These 25 pieces
also have a
minor but intentional difference
from later models
which allows
Jensen spot
any attempt
to fake a "first
production"
model.
 |
|
Serial
#
0000
Final
Pre-Production
Engine
with
a Couple
of
Friends
|
|
The
addition
of
the
Jensen
flywheel combined
with the 1940's
styling of the curved
turbine shell,
and the model
15 AC generator
all worked together
to create a
whimsical retro
look that the
collectors loved.
The addition
of the Jensen
flywheel also
"branded"
the model 95G
as a true breed
Jensen. The
open visual
design of the
rotor, transmission
and generator
has been a hit
with teachers
and power plant
public relations
departments
love that it
makes it so
easy to demonstrate
how their plant
works, even
to non-mechanically
inclined visitors.
It
took
a
few
years
to
come
to
be,
but
Jensen
now
has
a
an
all
metal
turbine
to
be
proud
of..
I'd
like
to
think
that
Tom
Sr.
would
have
approved. |
Many thanks go to Karsten, for the skillful application
of
his
unique
talents,
as
well
as
to
the
marvelous
group
of
Jensen
fans,
and
you
know
who
you
are,
for
their
invaluable
feedback
and
loyalty
to
the
effort
and
the
Jensen
company.
Without
the
parts
played
by
each
and
every
one
of
you,
this
project
could never
have
come
to such
resoundingly
successful
results. |
|
|
|
|
|