Yes either the pancake or radial PM in the RE bell housing
will be
used as a starter/gen. This is one item I will produce and
offer it to
the group if interested. 12 or 24v versions. Don't know the
weight
yet but it better be under 9Kgs. [19.9 lbs] Depends on what
is
attached to it. Ie how to interface to Tracy's rubber donut
flex plate
and how to incorporate a strain gauge into
its as well.
Doug in Japan
Tell me more about this-what is this we are talking about? The
stock RE
bellhousing containing an alternator or what? Starter-gens are
used only
in turbines that I know of.
Marc Wiese
Mark
I am having a 50mm or less thick motor combination generator made
up. I
mistakenly called it a pancake motor. Sorry. The design specs are
targeted
for at least 3 kw and the prototype unit will be able to fit in my
the RE
bell housing. Last time I spoke with George he said it would fit
but now I
am not so sure. It may have to be thinner. I've saw the prototype
when I
was in USA in October. Unknown at this time is how it will link
it to the
PSRU drive. Since the magnets are placed around the circumference
of a
metal disc then cutting mounting holes in that disc shouldn't be
a problem.
It will be design to slip on like a flywheel and the bell housing
will have
to be machined to fit hold the stator.
A real pancake motor would have the magnets on the face of one
disc and the
winding coils on the other. For several reasons that is not a good
way to do
it for our needs.
Other designs points to look at. Çan or should the disc rotor be
cut or
modified to act like a counter balance weight for the RE? IMHO..
no...
because of resonance problems but I would like to hear other
thoughts. I
have seen flywheels cut that way but then again they are more
torsionally .
stiff and a slight wobble it not noticable.
Wisdom dictates that aircraft engines should have a least two
sources of
electrical generation to provide the spark to the engine. Magnetos
are nice
and pretty reliable. So are permanent magnet generators. You can
always have
another starter/alternator made by GM hanging at the usual
mounting place
and make a little (very little) turbocompound system when the
battery
becomes charged up. Actually these size of motors and generators
are in the
high nineties in efficiency. Power controller however cuts the
final figure
down to about 85% to 91% depending on load.
Doug in Japan
Where do you get that high 90's efficiency number Doug? What size
coil wiring are you using
and how long is the wire for each coil. I assume all the coils are
in parallel?
Please send me a schematic of the motor and the controller.
I have data on motors that claim over 90% efficiency but that is
only initially
and for a short period of time until they warm up. Also if you are
using this
for a generator you must also calculate the windage drag of a large
diameter magnet
rotating at 5000 to 7500 RPM. Windage drag is proportional to
tangential velocity squared.
A 12 inch diameter magnet is moving 15,708 feet per minute or 261
feet per second
or 180 MPH at 5000 RPM. If the drag is only one pound that is 261
pound feet per second
at 5000 RPM or about 1/2 HP. If the generator can output 3 HP or 2
KW than
the efficiency is 3.5 mechanical HP in and 3 HP out or 86% for this
factor alone.
Also 2 Kw at 14 volts is 133 amps for a frame of reference. What is
the size of
the magnet required to generate 100 amps at 14 volts?
At 6000 RPM cruise HP loss would be about 40% higher.
BTW it was discovered in WW I that windage drag limited the RPM of
the rotary
radial engines then in use and started absorbing an excessive amount
of HP at 1800
RPM or so. This is the main reason the otherwise elegant radial
rotaries disappeared.
I am not saying it is not going to work. I am saying efficiency in
the high
90's not counting the controller is unlikely.
Paul Lamar
Hum,
Racemate makes a water pump mounted alternator. We need one that has
that and is a better fit for the low profile rotary. I'll talk to him.
He's busy, but.....if there is a market ? There is your second power
source. Also, I guess you want this starter-gen in the new 'smushed'
bellhousing being done?
How many amps and how many gallons per minute does this device produce
Marc?
If it is less than 35 gallons per minute it is unsuited to cooling the
rotary.
Paul,
They have several models-big to bigger, lots for American racing
engines, please go to their website and take a look. GPM-NO PROBLEM. One
is even a remote pump. Also, I have investigated Racemate's propensity
to undertake new designs and they indicate that if there is a suitable
market (#?) they would make casting and make a new housing/alt for the
rotary. However they are so busy they are in the throes of moving to a
much larger facility. www.racemate.com
(folloing lifted from alternator page)
RACEMATE
The entire Racemate is incorporated on the front of the water pump and
produces
15 amps, (also available with 22 or 32 amps). Racemate will maintain
peak battery levels for maximum starting power. Racemate is compatible
with
all high energy ignition systems
The Racemate Alternator is the first important charging system
advancement
since the introduction of the alternator. The Racemate Alternator
system is a unique, compact water pump/alternator combination assembly.
200 F water, 20 PSI system pressure pump inlet, restriction equal to 20
PSI
at 100 GPM,(full size hoses, no restrictors, 2 row single pass radiator
,
-12 AN lines from rear of heads)
PRO SPORTSMAN
Flow in GPM(gallons per minute)
RPM RACEMATE
1,000 23
1,500 36
2,000 49
2,500 56
3,000 70
3,500 83
4,000 94
4,500 107
5,000 119
5,500 133
6,000 145
6,500 155
7,000 163
7,500 176
8,000 182
SPORTSMAN
Flow in GPM(gallons per minute)
RPM RACEMATE
1,000 19
1,500 33
2,000 43
2,500 56
3,000 66
3,500 79
4,000 92
4,500 103
5,000 114
5,500 125
6,000 134
6,500 139
7,000 150
7,500 158
8,000 161
Page 7
CHEVY SMALL BLOCK
In addition to the specifcations common to all RACEMATE
ALTERNATORS (please see page 5), the RACEMATE
SPORTSMAN CHEVY SMALL BLOCK ALTERNATOR
has the following features:
Cam stop
Short 1955 Type/5.550 flange height
Pictured with race serpentine setup
Etc.
You need adobe to look at the catalogue-or go visit them, they are in
Kalifornia.
Marc W.
I am not interested but here is the info for anybody that wants to try it.
Sounds like it will work OK for an emergency alternator as long as you can keep
the engine running on 15 amps.
Paul
The Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/
Copyright 1998-2004 All world wide rights reserved.