Coomber rotary

[steamedlou]

I have a Coomber rotary that I purchased on ebay on its way from the UK at this time. It is from Brunnell models and comes with a dynamo which is unfinished. Has anyone out there built one of these. I have only seen photos of two of these on the whole internet and one is at the Brunnell site. Seems to be quite rare compared to others such as the Stuart line. I would love to find info on the engine or at least the dynamo. I hate to invest in a whole set of drawings from Brunnell for a little dynamo info.

 

[steamedlou]

Ok, has anyone built one to these Brunell Coomber rotaries? On 30 psi steam I can get about 3/4 revolution out of it before I have to give it a push. it turns freely and is well oiled. I have not taken it apart yet to figure out how the thing works. cant tell from looking at the outside. Not quite as obvious as a simple slide valve engine. So I'm clueless. I have a set of drawings I've ordered from Brunell and hope that will help me. But any help form this forum would be great. This thing seems to be rare as hens teeth. An internet search comes up just about empty on the Brunell version.

 

[steamedlou]

Got the Coomber rotary repainted, polished and running. The fly ball governor works so well that it slows the engine down too quickly and it stops. A little adjustment needed. This is now by far my fav engine. Still working on building the dynamo that will be driven off of it via the three belt sheave. Camera screwed up so no video of it running yet.

 

[steamedlou]

Ok got a little video here after some adjustments. I'm totally amazed the fly ball governor actually works and will roughly maintain a speed while steam pressure is being varied from 25 to 50 psi. Works better than I would have ever expected. love it.
[ame]http://www.youtube.com/watch?v=8CHjFLp2AVo[/ame]

 

[steamedlou]

I've got the renovation of the Coomber rotary and the construction of the Gramme dynamo completed and mounted. Engine runs beautifully and flyball governor actually works but the dynamo only puts out roughly 10-12 millivolts. Oh well looks cute anyway.

 

[Maxx]

Looks great and sounds good.
Are you sure you have the dynamo wired right?
It should put out way better than that.

 

[Shopguy]

Congratulations on a beautiful job.
If the field coils are wired up right you may still have to perform what we used to call polarizing the generator. Back when we still repaired generators as opposed to alternators it was a general practice to externally excite the field by momentarily applying a voltage to the field coils to initiate a basic residual magnetism. Probably 12 volts DC applied for a couple of seconds just to the field might just do the trick. Once done the field pole pieces retain enough magnetism to get started the next time.
Will be a really neat little model once you have every thing working just right and a lamp or two to show the generator is working.
Ernie Johnson

 

[steamedlou]

thanks guys. actually i do have residual magnatism in poles. got it by attaching a very strong magnet to it and running it also. wiring should be correct. but dont know what i should expect from this design. There was nothing in instructions which indicated output. i will keep trying. for sure i would love to run and LED off of it. which only needs about 3 volts.