Mosley Generator

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Trainsplanesandautos
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Joined: Sat Nov 23, 2013 6:25 pm

Mosley Generator

Post by Trainsplanesandautos »

I just purchased a Mosley generator, and it did not come with any instructions. I do have the never installed generator and regulator. I am inquiring to see if anyone has a instruction manual from Mosley that they could copy, or a original that I would purchase. My interest is in plumbing, and any maintenance required to keep it performing. Does it need a voltage regulator, has anyone done a LED setup. Thanks in advance.
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BAdams
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Re: Mosley Generator

Post by BAdams »

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ChuckHackett-844
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Re: Mosley Generator

Post by ChuckHackett-844 »

Be aware of the warning in the instructions "Do not operate the generator without load".

If the load fails (i.e. bulb, LED, whatever burns out or gets disconnected) and the generator has significant steam driving it, the RPM will quickly exceed the ability of the armature to hold together and it will "rats nest" destroying the generator.

I would suggest adding a bi-directional (the generator output is AC) Zener diode or TVS device across the output of the generator with a voltage rating a bit above (.5 volts?) the voltage measured when you are driving your 'normal' load. This device should be connected as close as possible to the generator to also protect against broken wires. This way, if the load fails and the armature RPM rises, the Zener/TVS device will conduct due to the increased voltage and create a load for the generator and saving your windings.

I have not tried this because I replaced my Mosley with a dummy.

If your generator is one of the newer types with a permanent magnet as a rotor instead of an armature it is more robust but I would still add this protection if it were mine.
Regards,

Chuck Hackett, UP Northern 844, Mich-Cal Shay #2
Owner, MiniRail Solutions, LLC, RR Signal Systems (http://www.MiniRailSolutions.com)
"By the work, One knows the workman"
BillF
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Joined: Wed Jan 18, 2012 3:47 pm

Re: Mosley Generator

Post by BillF »

An LED lamp will provide an excellent voltage (and therefore turbine RPM) regulator in itself. Just put a modest resistor in series with the LED, driving them directly from the generator. Choose a resistor so that its voltage drop at the desired LED current is about 0.1 Volt. (Ohm's law V=IR) The LED will draw a very small current until the voltage gets to about 2.0 Volts (depends on the color of the LED) and then the current rises very steeply. This is exactly the sort of characteristic that you need to stabilize the RPM of the turbine. The resistor helps to keep the operation stable. You can regulate the brightness of the LED with the steam flow to the turbine (within some limits).
BillF
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Re: Mosley Generator

Post by BillF »

Note added after seeing Chuck's reply: You can exploit the AC generator output by using two (preferably identical) LEDs in parallel, but wired in opposite directions, both in series with the same resistor. The idea is to use the LED itself as a "shunt regulator," which is preferable to the conventional series regulator ICs when the voltage of your power source varies widely with the load applied to it.
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Dick_Morris
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Re: Mosley Generator

Post by Dick_Morris »

I have a series of circa 2008 emails and posts to the old Live Steamers email list, mostly from Rich Dean, concerning the Moseley generators. He made a number of modifications to gain a higher output. He also regulated them electronically. One of his findings was that Moseley made a mistake in the design of his wheel resulting in the steam being fed to it backwards. From one of his emails, "The mods I do are extreme. Not for the squeamish! You can't tell it from the outside tho. Just as an example, I got 20 watts from the last test on air!"

Send me your email and I'll forward copies. I also have a number of photos showing his mods, but I'm not quite sure where they reside on my computer.

I didn't understand what Rich was saying until recently when I started work on making a 1/8 scale K-240 generator. There is an explanation of how the steam is used in the prototype in this thread. http://www.chaski.org/homemachinist/vie ... or#p444885. In the prototype the steam makes a couple of turns in the turbine wheel for better efficiency. My understanding is that Moseley's design simplified the wheel and the steam doesn't strike the wheel to be used efficiently in the model.

There is some other information at http://ibls.org/mediawiki/index.php?tit ... _Generator

You may not have any desire to do any of the modifications, but it's still interesting to see how they were done.
Trainsplanesandautos
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Re: Mosley Generator

Post by Trainsplanesandautos »

Thank you everyone great information.
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ChuckHackett-844
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Re: Mosley Generator

Post by ChuckHackett-844 »

BillF wrote: Mon May 23, 2022 5:10 pm An LED lamp will provide an excellent voltage (and therefore turbine RPM) regulator in itself. ....
Yes, right up until the LED burns out or a wire is accidentally broken ... I would choose extra protection of the Zener/TVS as close as possible to the generator.

BillF wrote: Mon May 23, 2022 5:10 pm .... Choose a resistor so that its voltage drop at the desired LED current is about 0.1 Volt. (Ohm's law V=IR) The LED will draw a very small current until the voltage gets to about 2.0 Volts (depends on the color of the LED) and then the current rises very steeply. ....

LEDs vary widely in voltage and forward current, especially white LEDs that might be used for headlights, cab lights, etc. which is what I assume is being driven.

Selection of a resistor will be trial and error because we do not know the voltage and current (wattage) that the generator will be putting out at any given point in time (steam pressure/volume, generator characteristics and load). If you know the voltage that the generator will be producing you can use the following formula to determine the required resistor value in ohms:

R = (Vgen -Vled) / Iled

Vgen = Generator output voltage (depends on total load, steam pressure/volume and generator characteristics)
Vled = LED "Forward Voltage" (from LED data sheet)
Iled = LED "Forward Current" (from LED data sheet ... do NOT use the "maximum forward current", use the nominal current. note: i would reduce it to 90% of the datasheet value)

So, for a 1.9v, 20ma LED and a generator output voltage of 10 volts):
R = (10 - 1.9) / (0.020 * 0.9) = 450 ohms

(Note: above is not strictly true because generator output is AC and LED is actually ON for less than 50% of the cycle but good enough for the purpose here)

Note also you need to know the resistor wattage:

W = (Vgen - Vled) * Iled

in the case above:
W = (10 - 1.9) * (0.020 * 0.9) = 0.1458 (a bit over 1/8 watt so a 1/4 watt resistor is good)

As I said, trial and error because the generator voltage output is dependent on the current it is having to deliver (number of LEDs and how much they are each drawing). As you connect more LEDs it will go down and hence the LEDs will dim and you will have to reduce the R value which will cause more current to be drawn, which causes the generator voltage to drop ... yada, yada ...

When testing, bring up the steam pressure (turbine RPM) slowly, if lamp lights bright enough for you at a reasonable turbine RPM (not screaming) fine. If not bright enough measure the turbine voltage (remember it's AC) and recalculate the resistor and retry.

You're good when you get the brightness you want at a reasonable turbine RPM.

If you get to a resistor value of zero (or, God forbid, negative which is possible) your LED is drawing more current than the generator can deliver ...
Regards,

Chuck Hackett, UP Northern 844, Mich-Cal Shay #2
Owner, MiniRail Solutions, LLC, RR Signal Systems (http://www.MiniRailSolutions.com)
"By the work, One knows the workman"
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