# Model multi pole Generator plans?



## steamer (Nov 13, 2011)

HI

Years ago a company listed in "Live Steam" as D&M had drawings and castings for a multipole generator model.

Does anybody have a line on a set of plans I can purchase for this or one like it?

Thanks!

Dave


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## stevehuckss396 (Nov 13, 2011)

PM research has a dynamo casting set but it looks awefully small


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## Jasonb (Nov 13, 2011)

There is mention of D&M oin Smokstak but no contact details as they are out of business. 

Is this also there genorator?

There are a couple of similar designs on this site look like scratch built though

Or Cotswold do a small one http://www.modelsteamenginesuk.com/acatalog/Electrical_Generation.html

J


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## steamer (Nov 13, 2011)

Thanks Jason,

That may be it. It sure looks like it.

I'd like something that looks like that but is half the size...like 3 1/2" instead of 7"

I can Engineer it, if I have something to go by.

Dave


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## steamer (Nov 13, 2011)

Thanks for the interest and support Steve....I'd like to direct drive this with a Potty Popcorn....right between the bearing pedestals.

I think it would like nice

Would like to do it as a permanent magnet alternator but have the old look.

I'd come up with a scale street light or something to run with it.  Maybe just an LED.

Dave


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## Jasonb (Nov 14, 2011)

I think the Cotswold one is about the size you are after.

I have heard of bicycle light dynamos being built into scale looking casings so that may be another option


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## Ken I (Nov 14, 2011)

I've seen guys put three and five pole DC motors from Slot & RC cars into authenic looking castings.

Some of the newer RC motors are permanent magnet "brushless" - three phase - which of course generate three phase output when used as a generator.

Ken


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## /// (Nov 14, 2011)

Ken I  said:
			
		

> ...
> Some of the newer RC motors are permanent magnet "brushless" - three phase - which of course generate three phase output when used as a generator.



That is the route I would take if I were doing this and the kit is definitely unobtainable.
The BLDC motors for RC use also have high pole counts to suit the look of the generator.
It's also reasonably simple to rewind for single phase output.


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## John Rudd (Nov 14, 2011)

///  said:
			
		

> The BLDC motors for RC use also have high pole counts to suit the look of the generator.
> It's also reasonably simple to rewind for single phase output.



R/C type brushless motors usually have 12 or 14 poles....

Rewinding for a single phase output means disassembling and removing the stator from its carrier..not for the faint hearted having already tackled this...

Easiest thing is to add six diodes in a 3 phase bridge config to change it to DC...
Just my 2c....


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## steamer (Nov 14, 2011)

Thank you all!

I will continue my research in the area's you all have described.  The key will be to not over power such a small engine, but have nice proportions. That engine is so nicely proportioned, I don't want to ruin that.

Dave


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## /// (Nov 15, 2011)

John Rudd  said:
			
		

> ...
> Rewinding for a single phase output means disassembling and removing the stator from its carrier..
> ...



True, however I think the idea had progressed to using a pilfered stator in an authentic looking casing, requiring disassembly anyway.

Taking the idea even further, and making it a Dynamo rather than an alternator... use the stator from an Outrunner BLDC (much easier to rewind) and make an armature with a commutator and brushes wrangled from an old drill/grinder/whatever... to make it look something like this:
Very cool!






I'm liking this idea more and more, think I might have to have a go at it myself! :big:


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## John Rudd (Nov 15, 2011)

///  said:
			
		

> True, however I think the idea had progressed to using a pilfered stator in an authentic looking casing, requiring disassembly anyway.
> 
> Taking the idea even further, and making it a Dynamo rather than an alternator... use the stator from an Outrunner BLDC (much easier to rewind) and make an armature with a commutator and brushes wrangled from an old drill/grinder/whatever..
> 
> I'm liking this idea more and more, think I might have to have a go at it myself! :big:



Me too...In fact anything that would yield a stator would suffice, old backup tape drives from computer servers spring to mind, they vary in sizes that would make a doable motor without incurring great cost...or how about the motor rotor from a power tool? problem there is the smaller size of motor laminations and the need to strip off the old windings ( been there done it, its a pain! )


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## steamer (Nov 15, 2011)

This is great that the "itch" is starting here!  Just remember we have to size these accordingly.  The Potty in my case is a tiny engine.....I won't be running the lap top with it, that's for sure!

 :big:

Dave


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## n4zou (Nov 15, 2011)

Jasonb  said:
			
		

> I think the Cotswold one is about the size you are after.
> 
> I have heard of bicycle light dynamos being built into scale looking casings so that may be another option



Tire driven bicycle Dynamos are friction driven from the tire. This requires it be spun very fast to produce full power. They are also designed not to be taken apart without completely destroying it in the process. Bicycle Hub Dynamos operate at low speed but they cost a lot and again can't be disassembled without destruction. If you want a small cheap (perhaps free) Dynamo look no further than a discarded or yard sale computer printer or a flatbed scanner. Rip it apart and dig out it's stepper motor. Here is a video of one in operation.
[ame]http://www.youtube.com/watch?v=B9emjJxXZ0c[/ame]


This link provides you with the information required to turn the multiphase AC output of a stepper motor into usable DC.
http://autonopedia.org/renewable_energy/Generators/Generating_Electricity_with_Stepper_Motors.html


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## steamer (Nov 15, 2011)

That is attractive !  and apparently not overpowering....I would wonder if it could be made to "look" better....

Dave


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## steamer (Nov 16, 2011)

How about the attached analysis?

A claw pole results in better performance....could use a ring magnet ..

thoughts?

Dave 

View attachment 32_Vitek_Hajek_nowy.pdf


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## steamer (Nov 16, 2011)

oh and by the way.....where's Zee?






He was looking at building one of these at one point....

Dave


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## steamer (Nov 16, 2011)

Actually Zee was looking at this picture as inspiration


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## steamer (Nov 18, 2011)

Found some interesting papers today on alternator design and construction.

Some very technical ...lots of meat here
http://www.utcluj.ro/download/doctorat/Rezumat_Florin_JURCA.pdf

Some a bit less technical and puts things in perspective for a small alternator.
http://www.otherpower.com/pmg2.html

 ;D

Dave


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## Hilmar (Nov 18, 2011)

Hi Dave,
  I see the words like Generator and Alternator tossed around. I am talking about the ones in HD for the home residence. and so. What is the difference between the two or are the booth the same? Did You ever had to use the one at Home?
Hilmar?


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## JorgensenSteam (Nov 18, 2011)

They use to use generators on automobiles, but they did not put out much voltage at low rpm, so they changed to alternators.

Both type devices move energized coils of wire or magnets past other coils of wire, inducing a current.

The current is the same, however, the generator has a commutator (the banded looking thing on the shaft) which reverses the polarity as the generator revolves, thus producing a voltage that does not change polarity (DC = direct current).

An alternate does not have a commutator, but only needs two slip rings, and produces alternating current and voltage that changes polarity as the alternator rotates. Direct current is produced by passing the alternating current through a bridge rectifier circuit, which has the mechanical analogy of a check valve.

Here is a nifty Cretors I ran across at a local Electrical Contractors office a few weeks ago.
If you push the button, an air compressor comes on, the engine runs, and the generator powers the street lights.

I told them I need to come over and take some measurements.


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## /// (Nov 19, 2011)

Technically, an alternator is still classed as a generator.
Alternator = AC generator
Dynamo = DC generator


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## steamer (Nov 19, 2011)

Hilmar  said:
			
		

> Hi Dave,
> I see the words like Generator and Alternator tossed around. I am talking about the ones in HD for the home residence. and so. What is the difference between the two or are the booth the same? Did You ever had to use the one at Home?
> Hilmar?



Hi Hilmar

Yes I have had to use one at home. ...and technically It's an alternator
 And Yes I am using them interchangably...and perhaps not correctly...appologies
Thanks /// for the explaination....I tend to ( that is TEND) to follow the verbage on the left side of your argument....but then again I'm a Mechanical Engineer..... :

Dave


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## steamer (Nov 19, 2011)

Technically, what I'm researching is a permanent magnet AC alternator.  The reason I'm looking at this is because it doesn't need commutation, or slip rings.

Slip rings are used on automotive alternators to supply power to the rotor coil...the rotor is the part that spins. In it is a coil of wire so wound that when current is supplied, it generates a magnetic field, North on one end and South on the other. 

This magnetic field, North and South are conducted through two multi lobed claw rotors with what look like interwoven fingers. As a result of this construction, the fingers have alternating north and south poles.

Varying the magnetic intensity (flux) of these poles will control the output of your car's alternator.  Now you know what the voltage regulartor on your car does....varies the input to the rotor windings to provide a constant output as you don't want your lights getting brighter or darker depending on how fast your engine is turning

For the application I have in mind...direct drive from a steam engine model, I am less concerned about a steady voltage.  To simplify the system, I am working this design study to use a permanent magnet for the rotor in place of the coil of wire on the automotive rotor....no slip rings required and no commutation.

A consequence of this is that the voltage will vary as a function of speed of rotation....but for a small demonstrator IMHO..I think that is a good thing.

I'm considering a "claw pole" rotor because it's pretty easy to make, can be machined externally to a simple disc shape which , visually, looks in keeping with the old time "generators", and it gives me some leeway to change magnets around in the rotor to change performance....IE it lets me adjust.  To do that , the rotor halves are split and an axially disposed ring magnet(s) are changed, added or subtracted, as required.  Most of the designs I've seen thus far include gluing magnets to rotors and such which seems a pain, and pretty permanent!

I think based on some of the articles I've read, a laminated stator is not really required for this application.....as I'm not trying to make a performance specification, just light up a few lights to amaze the kids and the kids at heart.

One article I read , for the stator poles, the author dragged a magnet around the yard and picked up all the magnetic sand (magnetite?) in the yard, mixed it with epoxy and cast the "pole" pieces in place!....the article attached in my previous post shows a alternator with no pole pieces whatsoever.....just coils.

I'm thinking this can be pretty simple..

Here's some inspiration

[ame]http://www.youtube.com/watch?v=eQteZyjTwmQ[/ame]

The pulley on the far end is to run a field generator....not needed on the model

Here's a model made by Jerry Howell
http://craftsmanshipmuseum.com/images/How ST H10.jpg

Dave


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## steamer (Nov 19, 2011)

Here's the other article I mentioned.

http://www.angelfire.com/ak5/energy21/magnetitecoregenerator.htm

Dave


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## /// (Nov 19, 2011)

Oops, sorry Dave if you thought I was correcting you.
I was answering Hilmar's question.
Probably should have addressed him to avoid the confusion.

I have been trying to find a nice donor stator to turn into an armature for a dynamo. Harder than I thought it would be.
Found a couple that looked perfect(number of poles/diameter/thickness) at Hobbyking, but they are out of stock 
Found another one that I have ordered, not quite what I wanted, but will experiment with that.

Simon


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## steamer (Nov 19, 2011)

Oh no worries ....Simon.... no offense taken or implied....good to get the terminology right.

Cheers!

Dave


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## John Rudd (Nov 19, 2011)

Take a look at this link...http://www.reuk.co.uk/DIY-2kW-Wind-Turbine.htm]

Here it describes how to make a 2kw wind powered generator...

How about building something on a smaller scale? Would make a small compact alternator with no need for slip rings...

Need magnets?...try here: http://www.supermagnete.de/eng/index.php or 
http://www.supermagnetman.net/


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## steamer (Nov 19, 2011)

Yes John, that was my point exactly.
Though I would rather not make an axial unit.
Dave


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