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#Post#: 779--------------------------------------------------
Dual Cylinder Double Acting Steam
By: lynx wind Date: November 8, 2013, 7:03 pm
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Hey Gang,
I received the PM Research 2A engines a couple days ago. Here
is a picture of the kit and the two engines linked together.
The next step is to attach a steel backer on the flywheels and
then attach the small NEO magnets and build the alternator coil.
A simulation in my HP calculator shows that the engine will
produce about 10 watts max. Yes, that isn't very much but its
just to show the system and to have some fun.
A quick test of the engines on air pressure brought the engines
to life. Well over 1000 rpm at 25 psi.
#Post#: 780--------------------------------------------------
Re: Dual Cylinder Double Acting Steam
By: crazyguy Date: November 9, 2013, 8:57 am
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Are you going to modify this? I thought you were building your
own?
#Post#: 782--------------------------------------------------
Re: Dual Cylinder Double Acting Steam
By: lynx wind Date: November 9, 2013, 9:45 am
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This is old technology with a new twist. The new twist is a
direct drive air core PMA which is much easier for a steam
engine to start against compared to a belt driven brushed
generator. I thought it would be fun and also might help Burnit
in his quest for turning fire into electricity.
I did a little test this morning with 20 psi air to just one
cylinder and got 14.5 volts out of the alternator. I am working
on hooking up both cylinders with steam today.
I will post a video at Lynx Steam. Its been a long time since I
have posted anything about steam to my YouTube channel.
#Post#: 783--------------------------------------------------
Re: Dual Cylinder Double Acting Steam
By: lynx wind Date: November 9, 2013, 2:10 pm
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Here's a video of the engine running on steam and making
electricity. I am using the Nessprojects boost rectifier to see
how it works for this alternator. Perfect! Once the engine
hits a high enough rpm it direct charges the battery.
This type of engine is very simple and is a good way to achieve
a self starting engine and double acting performance.
The boiler could be placed as tubing in a woodstove flue with a
reserve tank of water placed outside for hours of run time.
Pressure doesn't need to be higher than 20-30 psi to get good
work from a "simple" steam engine.
HTML http://youtu.be/3aE5xiUwLgw
HTML http://youtu.be/3aE5xiUwLgw
#Post#: 784--------------------------------------------------
Re: Dual Cylinder Double Acting Steam
By: burnit0017 Date: November 9, 2013, 5:27 pm
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Hi, yes it does help. Thanks for posting, it is really
inspirational. Any current readings. Have you tried using a 12
volt deep cell for a test load. Great work, thanks again.
#Post#: 787--------------------------------------------------
Re: Dual Cylinder Double Acting Steam
By: burnit0017 Date: November 10, 2013, 7:23 am
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Hi, what are variables used with the HP simulation?
Is it possible for this size of engine to have a higher power
output? Is there a max steam PSI limit for this style of engine?
#Post#: 789--------------------------------------------------
Re: Dual Cylinder Double Acting Steam
By: crazyguy Date: November 10, 2013, 9:01 am
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of course this generator is radial and makes more power than an
axial pma.
is there a way to take the moisture out of the steam before you
use it,?
Also in small model airplne engines there is a very fine
lubrcant in the fuel (kinda like a 2 cycle), is this possible
to have an oil /water mix so lubrication is automatic? y
#Post#: 790--------------------------------------------------
Re: Dual Cylinder Double Acting Steam
By: crazyguy Date: November 10, 2013, 9:28 am
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just a side comment : everytime i see mechanical things move
like that, i cringe and feel that the whole thing is going to
fly apart, just my phobia ;D
#Post#: 791--------------------------------------------------
Re: Dual Cylinder Double Acting Steam
By: lynx wind Date: November 10, 2013, 9:42 am
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@Burnit,
The upper limit of pressure you can apply to an engine has to do
with what the components can withstand. For this small engine
30 psi and 1000 rpm are safe limits. At 50 psi things that will
break are, piston rod will strip out of piston or crank pin.
Main bearing will oval and deteriorate. If treated well a
little engine like this could run happily for years.
I use an excel sheet with the formulas below. It still takes
some experience with different types of engines to know what the
F factor will be, and then actual results will be a bit
different too. For this engine the F factor is low because the
inlet is open for only about 25% of the stroke. Then when you
have HP calculated the max electrical output = HP X 750 watts/2
Horsepower Calculator
formula
HP = F X P X AREA X FT/MIN X RPM / 33000 FTLB/MIN
formula explained
HP = F FACTOR EFFICIENCY X PISTON AREA SQIN X FEET TRAVELED BY
STROKE X REVOLUTIONS PER MINUTE / 33000 LBS LIFTED 1 FOOT IN A
MINUTE
F FACTOR CONSIDERATIONS
Thermal efficiency affects F, such as heat interchange in single
valve designs
separate inlet and exhaust valves increase F
Thermal efficiency of design such as thin cylinder walls,
insulation reduce
heat loss and increase F
Double acting engines increase F as more of the stroke is under
pressure
Longer cutoff increase F, but increases steam use and therefore
efficiency
Shorter cutoff decreases F but lowers use of steam
Example:
By actual observation and testing a double acting engine with
50% cutoff
with a single hamonic slide valve, and good thermal design shows
and F of 46%.
100% would be perfect thermal insulation, no heat loss in
valving, and no
expansion of the steam. Power would be great but so would steam
useage.
An F factor of 25 wouldn't be unreasonable for a poorly designed
engine with
large heat losses, small ports, compression, and 30% cutoff.
The F factor is a multipler of the initial psi that takes into
account how much
of the stroke is under inlet pressure. It is an attempt to
arrive at the average
pressure condition in the cylinder. A single acting engine
could only
theoretically be under max pressure 50% of the revolution. A
double acting
could be 100%. Back pressure from exhaust port opening and
closing
during only a portion of the exhaust stroke is one
consideration.
Uniflow helps to exhaust away from hot side and raises F.
But this lowers the theoretical down to just 90% of the power
stroke.
#Post#: 792--------------------------------------------------
Re: Dual Cylinder Double Acting Steam
By: lynx wind Date: November 10, 2013, 10:48 am
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I did a calculation for a 1" bore x 1.5" stroke dual double
acting oscillating engine with 50psi running at 800 rpm. It is
1/3Hp and about 200 watts max depending on how efficient the
alternator is. I would expect somewhere between 100-150 watts
output.
At 65 psi and 900 rpm the engine puts out 1/2 HP or 375 watts at
the shaft.
Basically it is a 2x scaled up version of the little engine in
the video. Keep in mind it scales in 3D so it is 4x the
displacement and can handle more than 2x the pressure. RPM will
be lower due to the longer stroke.
This would be a popular size to manufacture for sale. There
just aren't any kits of this size. It's either toys or giant
machines.
The neat thing about steam is it is quiet and can be run indoors
as opposed to a gasoline or diesel generator. The sound is that
of a sewing machine and can be quieted by housing in an
insulated box. The exhaust can be sent to a hot water heater or
outside to drain.
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