Steam turbine generator

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Bill Shields
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Re: Steam turbine generator

Post by Bill Shields »

99.99% of LED are in the 1.5 to 3.6 volt range with lots of electronics to keep the incoming there.

doesn't take much of a generator to provide 10 to 30 ma to kick them off....

if you are going to have a battery anyway, a small gel cell will run your headlight all weekend with no charge. Plug it in when you are home charging your electric car...
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Greg_Lewis
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Re: Steam turbine generator

Post by Greg_Lewis »

The folks I've talked to who have working generators said one big drawback is the whine the create, and they rarely use theirs because of this. I made up the steam side for some castings I had and when I spin that thing up it's readily apparent that I could not tolerate that noise for an extended time.
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Celebrating 35 years of turning perfectly good metal into bits of useless scrap.
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makinsmoke
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Re: Steam turbine generator

Post by makinsmoke »

Bill,
Yes, led’s would be ideal, if we can find a decent temp led that replicates the old incandescent bulbs.

The “ring of fire” blue white leds work, but they just look terrible on a steam loco, imho. The HO and smaller scale guys have them.

I have spoken to old timers who said steam engineers and firemen suffered from hearing loss due to the turbo whine.

But even in our scales, it’s magical to open that valve, hear the turbo spin up, and watch the headlight come alive .
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NP317
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Re: Steam turbine generator

Post by NP317 »

I use warm-white LED bulbs in both my locos. One loco uses 3V., the other uses 12V. Both have E10 mini-screw bases.

https://smile.amazon.com/GutReise-10pcs ... 365&sr=8-6

Choose your color and Voltage. Just over $1 each in packs of 10.
Some packs include the E10 screw base sockets, of which I have MANY, now.
The E10 screw base fits the sockets in the Mercer-made lights, and others.

The resulting lighting is quite realistic.
And of course I cannot find my photos showing that...
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timmy wheeler
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Re: Steam turbine generator

Post by timmy wheeler »

This is a gold colored LED. I don't remember where I bought it, but it was off the internet.
Plymouth headlight.jpg
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jscarmozza
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Re: Steam turbine generator

Post by jscarmozza »

Looks like I'm going to have to come up with Plan C. I spoke to a few manufacturers by phone today and there's no way to generate the needed rpm to to develop voltage...so bicycle dynamos are out.

Regarding LED color, I have a 6 volt battery system for lights on one of my engines, the headlight is incandescent and a nice warm yellow color, the classification lamps are blue white LEDs and they look terrible even behind the colored lens. I should change them, but they're a royal pain in the neck to work on.
rkcarguy
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Re: Steam turbine generator

Post by rkcarguy »

Look into the 3-phase AC drone motors, they have tons of options on amazon and those things are high output for their size and weight, and turn over easily. Yes there will some circuitry involved in converting it to DC, but I think the output would be decent.
As others have posted, there are all kinds of warm white LED options now, instead of that awful blue-white color. LED's draw a fraction of the amperage that incandescent bulbs do, and with so little amps coming from a steam generator it would make a big difference.
I rather like the whine of a turbine generator, but I could see it being annoying or shrill to many because sound does not scale lol.
Wolfgang
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Re: Steam turbine generator

Post by Wolfgang »

I've built a number of these in 1/16 scale some decades ago and fooled around with flashlight bulbs and steam pressure regulators to keep the bulbs at optimum brightness with varying steam pressures, burning out a bunch of bulbs in the process...

I finally settled on a 3 watt warm colour LED. Turns out that the little turbine put out 3 watts electrical, thus was a good match except for the voltage available, which was too low to run the LED. Since the generator, really an alternator, put out AC current, I needed a rectifier. Thus I designed and built a voltage doubler/rectifier which runs the LED perfectly at the operating boiler pressure. I picket a pair of Schottky diodes for their very low forward voltage drop, for this purpose. This is important for such low voltage circuitry. This little circuit was placed under the cab floor in a little brass enclosure.

With a dropping boiler pressure the colour of the LED light does NOT change; merely the brightness (amount of light) decreases. This is a really nice feature.

The amount of light from a 3 watt LED is beyond belief. Running at night with the Montreal Live Steamers got complaints from the peanut gallery that the lights were way too bright! Thus we ran the little generator much slower than possible, reducing noise and increasing bearing life.

Even at full speed of 60,000 rpm the noise was not objectionable outdoors, whereas in the workshop, running on compressed air, it was barely tolerable.

About bearing life. I purchased a dozen 1/8" bore x 1/4" od ball bearings, lubricated with a light high temperature grease, from a manufacturer in California. The price at that time was less than $5 CDN apiece, with the custom lubricant. A sales engineer phoned me to discuss the application and recommended the lube. The promised life expectancy in this service was 100 operating hours.

These bearings were shielded, not sealed, even though sealing would have been better for life expectancy but the seal drag would have made self-starting problematic.

Consequently the initial bearing life was barely one night's use. What happened was that very fine corrosion dust from the alternator iron would find its way into the bearings quickly wearing them out.

The solution was to coat all iron surfaces in the generator with a thin coat of epoxy cement. This solved that problem and now the bearing life is as promised by the manufacturer: over 100 hours.

There is much satisfaction in opening a steam valve and have light instantly.

In Passing, the 2 cab lights, for water level and pressure gauge, use so little power as not to affect the headlight's brightness at all.

I think these little demons are a very nice addition to any steam locomotive. w
jscarmozza
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Re: Steam turbine generator

Post by jscarmozza »

Wolfgang, you touched on two issues that were problems for me when trying to build a functioning steam turbine and generator. I always had trouble finding the proper bearings for a 1" scale turbine generator (never did find them), and I could never find a source of iron for the field coil, I would wind up using steel plates and they don't perform as good as iron I am told. These were a couple of the many problems that caused me to give up on building a turbine generator, and they looked pretty ugly too.
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Harold_V
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Re: Steam turbine generator

Post by Harold_V »

jscarmozza wrote: Thu Jun 17, 2021 3:01 pm I could never find a source of iron for the field coil,
That shouldn't be too difficult. The cores from transformers would be an excellent source (assuming it's thin enough), especially considering that you'd be dealing with rather small pieces. All they are is what is commonly known as Armco iron, which is carbon free iron. Transformers from microwave ovens might be a good source, as they're quite large in size.
I would wind up using steel plates and they don't perform as good as iron I am told.
As I understand it, any hint of hardness (promoted by carbon content) tends to allow residual magnetism. Mild steel has a <.30% carbon content. You'd also enjoy better success using silver instead of copper for the windings, although that may be expensive these days with silver running above $27/ounce.

H
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RET
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Re: Steam turbine generator

Post by RET »

Hi,
A couple of things.

First, Harold is correct. When it comes to the stator, the correct choice of steel is important. What you need is a very low hysteresis material and for most of us, the best source would be old transformers. You need a material you simply can't magnetize permanently at all.

Bill Huxhold gave me the stator sheet material he had left over from the run of turbogenerators he made and it is .014" thick and thinly coated for electrical insulation ( Bill's units worked very well, especially the 1/8" scale ones).

If the leaves aren't insulated from each other, you get eddy currents which take all the potential power you can generate; the stator heats up and there is no electrical output. Also make sure that you remove any burrs from the drilled or machined holes to prevent shorting the leaves together since this will also allow the creation of eddy currents.

Second, Most of the suggestions made for the form of the turbine blades will "kinda" work, including allowing the jet to go "splat" against the teeth of a gear, but most of them will not be very efficient and the resulting turbogenerator will be "steam hungry" to varying degrees. One of the many difficulties you will run into is to make a rotor that will hold the high strength permanent magnets that are required and stand up to at least 40,000 rpm. without coming apart.

As I said before, motors don't usually make good generators because the requirements are different so they are built differently. A generator needs relatively few windings with a very low electrical resistance, whereas a typical motor has more windings. If you want to test a motor as a potential candidate for a generator, drive it with a Dremel since a Dremel will typically spin up to 24 to 30 thousand rpm. depending on the model.

The basic generator construction needs to be a two pole rotor with a three pole stator. This configuration reduces "cogging" to a minimum. These units can be made successfully, but it does take a lot of pretty precise machining and there are a number of design and construction pitfalls or "Oopses" to overcome.

Maybe this will help a bit, or at least get thoughts pointed in the right direction.

Richard Trounce.
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Bill Shields
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Re: Steam turbine generator

Post by Bill Shields »

Richard:

you are right on. My brother in law runs a shop that makes 'laminations' for such applications.

when 'stacked' they are glued together with a variant of super-glue to insulate them from one another, and usually 'skewed' to reduce the 'cogging'.

you should see the stamping tooling they make to stamp out laminations that a .008" thick and not create a burr...
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