Steam turbine generator

This forum is dedicated to the Live Steam Hobbyist Community.

Moderators: cbrew, Harold_V

EOsteam
Posts: 240
Joined: Thu Jan 31, 2013 1:33 am
Location: Pendleton, Oregon

Re: Steam turbine generator

Post by EOsteam »

Here is the turbine wheel out of one of my dental high speed handpieces. They routinely turn 300,000 to 400,000 RPM. I haven't measured the width of the turbine but it is certainly less than .25" I can vouch that the high speed in conjunction with with either a carbide or a diamond bur is what does the cutting. There is not much torque available. The Air Path is almost 360 degrees from the inlet to the exhaust outlet. The outlet is a much bigger tube.
We have since switched to electric geared handpieces that turn roughly 200,000 RPM with almost unlimited torque.
TurbineWheel.jpg
TurbineWheel-2.jpg
TurbineWheel-3.jpg
Hope this helps!

HJ
Wolfgang
Posts: 184
Joined: Fri Jul 03, 2015 9:47 am
Location: S-W Ontario
Contact:

Re: Steam turbine generator

Post by Wolfgang »

Hello HJ,

Thanks for the pics, most informative.

Question: What is the size of the air nozzle, and what is the air supply pressure?

If Kimball reads this, I'd appreciate the same information for his dental turbine.

Thanks, Wolfgang
User avatar
Greg_Lewis
Posts: 3014
Joined: Wed Jan 15, 2003 2:44 pm
Location: Fresno, CA

Re: Steam turbine generator

Post by Greg_Lewis »

For what it's worth, here are a couple of snaps of one I saw in the shop in Durango many years ago.
pyle1.jpg
pyle2.jpg
pyle3.jpg
pyle4.jpg

Closeup cropped from first photo
pyle5.jpg
Greg Lewis, Prop.
Eyeball Engineering — Home of the dull toolbit.
Our motto: "That looks about right."
Celebrating 35 years of turning perfectly good metal into bits of useless scrap.
jscarmozza
Posts: 599
Joined: Mon Mar 03, 2014 5:09 pm

Re: Steam turbine generator

Post by jscarmozza »

I rigged up another test apparatus and tried to be a little more scientific this time. The apparatus consisted of two 12 volt bulbs in parallel with ther own switches. First I checked the circuit with a 12 volt battery and measured the current, which was 1.8 amps for each bulb, I disconnected from the battery and connected the 12 volt dc motor with Kimball's turbine wheel in place and spun it with air at 90 psi. Only one light was switched on, it lit but was dull, and the amperage reading was between .8 and .9 amps. I tried it a few times and got the same result; there was definitely drag on the generator, so much so that when the air was removed it stopped rotating immediately, with no load it would coast to a stop in 10 seconds. The other wheel failed to generate at all, the RPMs never got as high as Kimball's wheel. Regardless that the wheels were not in a housing when tested, I still think Kimball's wheel form is the better choice for a small turbine. I know that I'm going to get an argument from some, but I can't see how these little turbines will work on the principles of a full scale prototype; the laws of physics don't change but things have to react differently when scaled down. I think these tiny turbines are nothing more than pinwheels, as the scale gets larger they may react more like the real thing, but for 1" scale and smaller, I'm convinced they're pinwheels.

Now on to the generator!
John
Bob D.
Posts: 381
Joined: Thu Jun 21, 2012 10:43 pm
Location: Saco, ME. USA

Re: Steam turbine generator

Post by Bob D. »

That's an interesting test. Did you measure a voltage while you were measuring the .8 amps? Then you know the watts developed. I think you should up the ante on your test mule motor and go to something with known specs. Tower Hobby or Horizon completely spec out a wide variety of 1/10 scale RC buggy motors. They have smaller stuff too that may be appropiate for actual use.
I think there is going to be quite a difference with steam compared to compressed air. There must be more mass hitting the turbine on the simple view of things. I don't know what the velocity is of a jet of air at whatever psi but I'm pretty sure steam is greater and getting supersonic. Just those two items would be a tremendous impact on performence of this simple test wheel. I think the housing comes into play trying to capture the far greater expansion of steam over compressed air.

Bob
3/4" Juliet II 0-4-0
3/4" Purinton Mogul "Pogo"
3/4" Hall Class 10 wheeler
3/4" Evans Caribou/Buffalo 2-8-0
3/4" Sweet Violet 0-4-0
3/4" Hunslet 4-6-0
3/4" Kozo A3. Delayed construction project

1 1/2" A5 Camelback 0-4-0
User avatar
Dick_Morris
Posts: 2841
Joined: Sat Jan 04, 2003 2:09 pm
Location: Anchorage, AK

Re: Steam turbine generator

Post by Dick_Morris »

There is quite a bit of information in this thread - http://www.chaski.org/homemachinist/vie ... richd+pyle
Rich_Carlstedt
Posts: 1754
Joined: Sat Dec 21, 2002 12:16 am
Location: Green Bay Wisconsin USA
Contact:

Re: Steam turbine generator

Post by Rich_Carlstedt »

Rich Dean has it all if you read the previous post...enjoyed talking to him back about 20 years ago when I first bought the castings from Barry
I know i am resurrecting this thread but thought it would be good to post the drawing I made back then that details the Vane construction for the PYLE generator for those who have not seen the real thing. Please know that Rich Dean said the shown vanes are backward for the correct rotation, but it worked in the Moseley Generator.
I forgot to mention in the drawing that there are 27 vanes to the wheel
I think the reason for the odd number is it gives less vibration/harmonics

Rich

Image

PS

I was at the Chicago Machine Tool Show in 1976 or 1978 and saw the Vane Wheels being made on a Servo CNC mill at the show . This would be close to what a Sherline CNC Mill looks in size. The Salesman asked me if i knew what the mill was doing and I said "Yes" and told him what the wheel was for. He was shocked and said no one else knew except for me...but of course there were not many live steamers there at the show
RET
Posts: 960
Joined: Wed Jun 07, 2006 8:36 am
Location: Toronto, Canada

Re: Steam turbine generator

Post by RET »

Hi,

This is an old thread on turbogenerators, but recently I talked to Bill Huxhold about the ones he made and I have some important advice to pass on to anyone who may have one of his units.

Bill designed his turbogenerators to run at about 40,000 rpm. using 40 psi. steam pressure. That is why each one of his units was furnished with its own stainless globe valve (which he also made). In operation, the valve was to be used to throttle the steam supply so that the pressure to the turbine was kept near Bill's design pressure of 40 psi. As you can easily imagine, running one of his generators at full boiler pressure would result in a severe overspeed condition which would likely result in a catastrophic failure. It would be a shame to lose one of Bill's "creations" because it wasn't properly installed or operated.

Thus, to run his generator units as intended, you need to add a Tee after the valve so you can measure the pressure at that point and use that connection to set the globe valve opening. Once the valve is set and locked, the pressure gauge can be removed for normal running.

Since water droplets in the steam will cause pitting damage to the turbine over time, this type of installation has the further advantage that the adiabatic expansion of the steam as it goes through the valve will cause some of the droplets to flash back into steam, thus making the steam the turbine sees drier.

Because of the curie temperature limitation of the magnets used, it is prudent to mount the turbine to minimize heat transfer from the boiler to the generator and to also avoid long piping runs between the control valve in the cab and the generator to minimize condensation in the steam.

Hope this helps.

Richard Trounce.
jscarmozza
Posts: 599
Joined: Mon Mar 03, 2014 5:09 pm

Re: Steam turbine generator

Post by jscarmozza »

I'm resurrecting this old topic because I gave up on plan A and I'm onto plan B, and since there is nothing new under the sun here, I figured at least a few of you guys have thought about this or tried it. Have any of you tried to adapt a bicycle Dynamo to your engine or train to generate electricity? I have been kicking this idea around for a while but always ran up against where to get the rpm's, the little bottle type bicycle dynamos run off the rim of a 28" bicycle tire and there's no place with that much speed on a 1" scale. Just recently I learned of bicycle hub dynamos, and wondered if one could be adapted to run off a tender wheel or axle? Have any of you thought about or tried this? I researched hub dynamos and have come up short on dimensions and performance data so I can't determine if this idea is even viable. Fitted with a small magnetic clutch it could also act somewhat like a dynamic brake on downgrades...or have I just lost my mind. Anyway, I like to have your thoughts on the matter.
User avatar
Bill Shields
Posts: 10460
Joined: Fri Dec 21, 2007 4:57 am
Location: 39.367, -75.765
Contact:

Re: Steam turbine generator

Post by Bill Shields »

Some things just don't scale down well.

big problem is speed control..as mentioned, not much rotational inertia here, and a couple of psi difference and speed change is immediate and death and destruction on the bulb / led. pressure regulators for the flows required are very difficult to build and keep reliable.

Yes, there are electronic circuits that can handle these differences, but what a PITB just to have a bulb / generator.

bicycle generator(s) are not really applicable, especially since you want light at low speeds / stopped...which will require a battery...

A fake generator to provide a wisp steam out the stack and batteries hidden elsewhere is this practical engineer's solution.
Too many things going on to bother listing them.
User avatar
makinsmoke
Posts: 2260
Joined: Thu Jul 10, 2003 12:56 pm
Location: Texas Hill Country

Re: Steam turbine generator

Post by makinsmoke »

Why not use the generator to charge the battery, and run your circuits, lights, whatever off the battery?

Btw, the Santa Fe and others had truck hung, axle driven generators on many of their passenger cars and cabooses.
I’ve thought of the bike gens to charge the battery circuit.
jscarmozza
Posts: 599
Joined: Mon Mar 03, 2014 5:09 pm

Re: Steam turbine generator

Post by jscarmozza »

The lights on one of my Atlantics are battery powered and it works fine, but by the end of a long day's running the batteries are dead. I was thinking along the lines of Makingsmoke and using a generator with a voltage regulator and rechargeable batteries to keep the lights burning and recharge the batteries when possible. I think you can get some pretty low voltage LEDs, the question is what is the performance capability of the generator, rpm/torque vs voltage out put. I'm probably not looking in the right place, but I can't find any performance data on these things, not to mention dimension information to see where I can hide it.
Post Reply