Three Phase Generator Question

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Pipescs
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Three Phase Generator Question

Post by Pipescs » Mon Sep 30, 2013 8:30 pm

Not to be distracted from my various other projects I have been packing away Model Airplane projects. In the process I took a couple of three phase Outrunner Motors out of a drawer and spun them up with an electric drill. No where near their operating speed and checked voltage.

Has anyone ever seen anything on powering these with a steam turbine wheel to act as a large scale generator?
DSC_1362.jpg
Charlie Pipes
USMC Retired

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hammermill
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Re: Three Phase Generator Question

Post by hammermill » Mon Sep 30, 2013 8:39 pm

are they permant magnet motors??? is driving they for a output is easy. feed to a rectifier bank and off you go no exciter needed

Asteamhead
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Re: Three Phase Generator Question

Post by Asteamhead » Tue Oct 01, 2013 3:49 am

Hello Charlie,
You may use any 3-phase brushles motors as generators, sure. In case you want DC voltage output, please connect to a 3-phase rectifier bridge of 6 HF (high freqcency) diodes. But you may use AC by just connecting two phases at reduced output power instead.
Main disadvantage of those outrunner types is limited rpm yet. Inrunner types are matching with a turbine a lot better. This is due to it's low torque but high rpm potential at constant steam consumtion. Wouldn't recommend any reduction gear due to both friction and wear!
Good luck,
Asteamhead

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Pipescs
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Re: Three Phase Generator Question

Post by Pipescs » Tue Oct 01, 2013 4:20 am

Interesting question but I am not going to pursue. My Rust Bucket is getting all my time right now.
Charlie Pipes
USMC Retired

Current Projects:

2.5 Baldwin 2-4-2/2-4-4/0-4-4 Conversion (What ever)
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jschoenly
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Re: Three Phase Generator Question

Post by jschoenly » Tue Oct 01, 2013 7:41 am

In my far too many projects on the list, I'm working with the same type motors for a Turbine, probably the early Pyle. If you search for RET's posts on turbines he describes very well a pelton wheel for the turbines he worked on. I made up a prototype wheel and very (VERY) crude jet to spin up a tiny outrunner I bought at a model airplane show. With a multiphase rectifier and a few power resistors I was able to measure nearly 1 watt of power output on the DC side at about 1.5-2 volts (can't remember, didnt' write it all down) running in the rnage of about 25,000 rpm. This was on the output side of a regulator set to 3-3.2 volts so i was obviously not getting the fully voltage. I was trying to find the pictures but I'm at a loss right now. The motor was about .75" diameter and maybe .25 long and the turbine wheel i made was .187" wide x 1" diameter with the double pelton cups. Used a tiny .125 diameter by 1mm woodruff style cutter for the cups and 24 around the diameter.

I plan on trying some much larger outrunners in the future that would still work in our scale sizes and I expect you can get a decent amount of power out for our uses. What I'm not sure is how much of a steam hog they may but, but i did at least prove the concept. Fun project and would like to get back to it. If I only had more time.....
Jared Schoenly

Cabin Fever Expo
Model Engineering of all sorts.....

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jschoenly
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Re: Three Phase Generator Question

Post by jschoenly » Tue Oct 01, 2013 12:00 pm

Got the pictures (with the help of a friend reminding me of old text messages....)

The only bearings here were the motors and I would not relay on them for long. I have a few designs mostly detailed for real prototypical housings and again - Hopefully - will have some time for this stuff soon...

Image

Image

Image
Jared Schoenly

Cabin Fever Expo
Model Engineering of all sorts.....

Asteamhead
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Location: Germany, Duesseldorf

Re: Three Phase Generator Question

Post by Asteamhead » Tue Oct 01, 2013 4:25 pm

Please, get some more about brushless turbogenerators (TGs).
You will get the same performance by using a simple gearwheel made of aluminium instead a sophisticated turbine wheel with blades.
To seperate the generator (with bearings) from the steam turbine you may use piston rings in combination with a disk wheel. Both mounted onto the shaft by a slight press fit.
Finest type of brushless motors may be the Faulhaber of different sizes. Swiss made, expensive, sorry!
I recommend to hold the combination in the outer case by means of O-rings.
The (venturi) nozzle may be just 1 / 32 " for a steam preasure of 100 psi or more.
Continous output is >= 8 W @ 8 pounds of steam per hour.
Asteamhead
Attachments
AEG turbo generator 5 inch.jpg
TG 5 " scale, 8 W / 12 V
TG mit FH 1628 ZSB.pdf
Construction image of turbine, sealing and FH generator
(481.55 KiB) Downloaded 146 times
DE_1524_BSL_MIN.pdf
Faulhaber data sheet
(255.39 KiB) Downloaded 94 times
Turbogenerators_800x600.JPG
Sets of different TGs

thunderskunk
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Re: Three Phase Generator Question

Post by thunderskunk » Tue Nov 12, 2019 8:17 pm

Well I’m glad I found this... Got me an inrunner 6V to play with thinking “hmm, this motor has three leads. I wonder which one is ground.”

Did not realize it would be three phase. Didn’t even cross my mind. I’m having enough trouble finding a 6V dimmable warm white LED, haha.
"We'll cross that bridge once we realize nobody ever built one."

hoppercar
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Re: Three Phase Generator Question

Post by hoppercar » Thu Nov 14, 2019 7:29 am

Wrong chat group

jscarmozza
Posts: 331
Joined: Mon Mar 03, 2014 5:09 pm

Re: Three Phase Generator Question

Post by jscarmozza » Thu Nov 14, 2019 8:45 am

In the Sept- Oct & Nov-Dec issues of Live Steam there was a well done build article for a 3 phase steam generator in 1" scale.

jscarmozza
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Re: Three Phase Generator Question

Post by jscarmozza » Thu Nov 14, 2019 8:46 am

Oops! The year was 1999.

rkcarguy
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Location: Wa State

Re: Three Phase Generator Question

Post by rkcarguy » Thu Nov 14, 2019 12:44 pm

Asteamhead wrote:
Tue Oct 01, 2013 4:25 pm
Please, get some more about brushless turbogenerators (TGs).
You will get the same performance by using a simple gearwheel made of aluminium instead a sophisticated turbine wheel with blades.
To seperate the generator (with bearings) from the steam turbine you may use piston rings in combination with a disk wheel. Both mounted onto the shaft by a slight press fit.
Finest type of brushless motors may be the Faulhaber of different sizes. Swiss made, expensive, sorry!
I recommend to hold the combination in the outer case by means of O-rings.
The (venturi) nozzle may be just 1 / 32 " for a steam preasure of 100 psi or more.
Continous output is >= 8 W @ 8 pounds of steam per hour.
Asteamhead
Wonderful craftsmanship as usual Asteamhead!
This post makes me want to play with building one of these even though I don't have a steamer lol. These aren't much different than a turbocharger, just tiny. Most important, is getting a seal that will separate moist steam pressure and heat from the electric motor/bearings without inducing a bunch of drag on the shaft...probably a good trick. I honestly think it would be best to use a motor with a long shaft, and have a vented "center section" with a housing that simply cleared the shaft by a few .001"s. I wouldn't think that a little bit of leakage through the housing would affect the efficiency all that much?

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