Double Dynohub: 2 Sturmey Archer generators in one - to be steam driven

[BaronJ]

*** = cigarette, probably hand-rolled with very little tobacco, so just about the smallest red glowing thing you can have....
Jam-jar? - Glass container for Jam, so you need to know what that is! Often about a half-pint size, or thereabouts.
Jam is a Fruit Jelly, fruit preserve using its natural gelatin or setting agents, like LOTS of sugar!
Maybe your Grandma made it? - My Mother did - Lots!

Jam-jar, rhyming slang for "Motor Car" !

 

[BaronJ]

Hi K,

Thanks Baron, I was planning some more testing today - but was nervous of toasting windings with the buck controller set at 12V... and I plan to use a 5W 12V bulb as the load.... - but first I'll try a sub-1W, and 3W bulbs I think? I'm using my battery drill as a motivator, so limited on speeds and control. (I need 3 hands!).
I'll post results later.
K

5W 12 V = 29 ohms. I bit low for initial testing.
3W 12 V = 48 ohms
1.5 W 12 V = 96 ohms.

The down side of using bulbs is the great difference between hot and cold resistances.

The idea of using known 100 ohm resistors is that you can put two in parallel and you now have 50 ohms, four and you now have 25 ohms. So for a given speed you have a VR curve that you can use to work out just what power you have available.

 

[Steamchick]

Good stuff! I'll order some if I don't get any sense from bulbs...
thanks,
K

 

[Steamchick]

"*** in a jam-jar" = a lamp that won't illuminate enough to see anything with... as used in context with Lucas and Wipac electricals on motor-bikes. I don't think the Jam-jar = car analogy works in this context. Did you have a British bike from the 50s? fcheslop did, referring to his "oilfield"!
K

 

[Steamchick]

Thanks for t'chat.
Interesting!

 

[BaronJ]

"*** in a jam-jar" = a lamp that won't illuminate enough to see anything with... as used in context with Lucas and Wipac electricals on motor-bikes. I don't think the Jam-jar = car analogy works in this context. Did you have a British bike from the 50s? fcheslop did, referring to his "oilfield"!
K

Unfortunately yes !

Though I lost my bike license some years ago when I renewed and didn't notice that it hadn't been put on the new one. When I did notice, I was told that they had no record of it.

More recently I've noticed that I can no longer legally drive anything over 3.5 tons. Not that I'm bothered nowadays.

 

[BaronJ]

Hi K,



5W 12 V = 29 ohms. I bit low for initial testing.
3W 12 V = 48 ohms
1.5 W 12 V = 96 ohms.

The down side of using bulbs is the great difference between hot and cold resistances.

The idea of using known 100 ohm resistors is that you can put two in parallel and you now have 50 ohms, four and you now have 25 ohms. So for a given speed you have a VR curve that you can use to work out just what power you have available.

Hi K,

Re-reading this post, don't use the voltage regulator when testing !

 

[Richard Hed]

Thanks Baron, I appreciate the comments.
Some of things I understand are the equations involved - but I like the diagram you included! However, when I was quoting the rating of the generator, I think this is a single point on a variable curve of power/speed/voltage - which defines the current limitation for which the generator has been wired. A Rating of 6V 3W defines the current as 0.5A. - and impedance of 12 Ohms. However I guess this is not just the resistance of the windings (6 Ohms), but the resistance + impedance of the coil and core at the frequency generated by the shaft speed and number of poles + resistance of load..?
But I have experience of dynamos, on old motorcycles where there was "adequate" input power, and I converted from 6V to 12V by re0-wiring the controller to keep the field managed by switched 6V supply, and the armature fed a 12V battery and the lights, ignition, etc. - In that case, the limiting factors were the current in the armature and field coils - too much and they would simply overheat/burn-out. But the increased voltage across the armature didn't seem to affect it. (I did thousands of miles and had good 12V lighting!).
In the case of your comments about power, yes, you are right, but that is a different problem for me in increasing the power input, as I am changing from a couple of legs (for the Bicycle-driven generator) to a steam engine powered toy. (I have a 60psi boiler with a lot of steam generating capacity for this application, just need to build the engine to the generator and see what steam pressure is needed for an adequate speed to generate..). However, I am worried that the generators are designed for 6V AC across the internal resistance of 6 Ohms, and I'm not sure if that suggests I'll burn-out the generator by allowing it to generate at 12V, as surely that will double the generator internal current? - Unless I limit the current with an appropriate external resistance? - Which constrained me to running the buck controller at 6V. output... on a load "not exceeding" 6W for the pair of generators.
What will happen to the generators if I allow the Buck controller to output at 12V? I have an idea that the generator will need to be protected by not exceeding 6W total load? - This will drop the current demand to 0.5A - so should I be OK? - With the Dynamo case that I used on 4 motor-bikes, the double voltage allowed nearly twice the external load wattage - as the current did not exceed the original designed limits. (10A. in that case). But it was limited and controlled by switching the field from the regulator. The Bicycle generators have no field control, so will running the generators faster with a 12V setting on the buck cause them to run too much current and burn-out?
I also have some experience of a few motorcycles with PM rotors and Stator windings, with "switched" loading and rectifier but no control. These were rated 6V and 60W but easily converted to 12V and between 90 and 110W - depending on when-made / what-design for wiring. (Simply jon 2 of 3 wires together, and then feed the rectifier bridge). This 12V version used a Zener Diode to regulate system voltage and dump surplus electrical power to heat... - But I never managed to understand exactly what the joining of 2 wires really did? I thought they were 3 wires from a delta wound stator, but shorting 1 phase shouldn't be the most efficient way to get more volts/more power should it?
On bicycles... the wheel speed is of the order of 200rpm at 15MPH I think? - so these hub generators were designed for that sort od speed - which is not a difficult speed for model stationary engines. I have 3 possible engines, that run at ~200, 450. and 850 rpm when coupled to my usual Fridge compressor air supply. Therefore with steam at higher pressure, and selecting the most suitable engine from those 3, I think I can make the generator work nicely.
Attached is another engine and a bicycle "bottle dynamo" that lights the bulb easily on the same fridge compressor. Although this bulb is only 0.5W or less.
Keep writing,
K

Where did you get that belt for the generator?

 

[Richard Hed]

*** = cigarette, probably hand-rolled with very little tobacco, so just about the smallest red glowing thing you can have....
Jam-jar? - Glass container for Jam, so you need to know what that is! Often about a half-pint size, or thereabouts.
Jam is a Fruit Jelly, fruit preserve using its natural gelatin or setting agents, like LOTS of sugar!
Maybe your Grandma made it? - My Mother did - Lots!

We still make jam. Also preserves which is NOT jam but certainly similar. If you buy "preserves" today, it usually is not preserves but jam. There is also Jelly which is not preserves or jam. When I was a kid (last week), we could get all kinds of tobacco, but now it is mostly pipe tobacco for cigarettes. I bought some "Players" tobacco in Canada years ago and it was quite frankly one of the best tobaccos I ever smokt.
Jam jars are too over priced. I thimk it has to do with the fact that not enough peeps make their own preserves and what not. When I was a kiid (last week) almost all the Moms did some kind of preserves--they had to during the war and naturally, we did green beans, peas, all kinds of fruits and even some meats that way.

 

[Steamchick]

Hi Richard, Sorry, I can't remember where I got the belt. I Collect things "for later use" so have a few odd lengths. It is probably off a vacuum cleaner, hand-held power planer or other power tool, or some other miscellaneous garden lawn mower or something. Do you want one? Tell me size and I can see what I have. I recently bought a shorter one (as I never have the right size when need one) for my Black and Decker planer. But I think I have one similar to the one shown...?
K

 

[Richard Hed]

Hi Richard, Sorry, I can't remember where I got the belt. I Collect things "for later use" so have a few odd lengths. It is probably off a vacuum cleaner, hand-held power planer or other power tool, or some other miscellaneous garden lawn mower or something. Do you want one? Tell me size and I can see what I have. I recently bought a shorter one (as I never have the right size when need one) for my Black and Decker planer. But I think I have one similar to the one shown...?
K

Thanx for the offer, but I am only looking in order to buy extras at a proper price. when Enco was alive, they were selling the scuzzy little pieces of crap for 18$US. It's worth maybe 5$, at least I am willing to pay 5. I have some that I managed to get off the internet, howefer, they are supposed to be abut 5/8 " and these are half that. They work, but I'm afraid they will bust sooner (obviously). I have two or three now, so I'm safe. I managed to find a very long (29") washingmachine (no, dryer belt) belt that I will try to cut up and glue together if I run into trouble on that. But in the mean time, I keep an eye out for anything or anywhere that might have them for the correct price.

 

[Sprocket]

Steamchick;
Thanks for the explanation. Individually all the words were familiar, I just couldn't see how a cigarette in a glass jar had anything to do with a motorcycle. I had a vision of a jar full of smoke, not the very faint light. Lucas was even familiar, and we still make jam, although a lower sugar variety.
My wife mad a batch of strawberry jam today in fact.

 

[Steamchick]

Wish I could enjoy some of that Strawberry jam! - Yum! - Lucky you.

 

[Steamchick]

Thanx for the offer, but I am only looking in order to buy extras at a proper price. when Enco was alive, they were selling the scuzzy little pieces of crap for 18$US. It's worth maybe 5$, at least I am willing to pay 5. I have some that I managed to get off the internet, howefer, they are supposed to be abut 5/8 " and these are half that. They work, but I'm afraid they will bust sooner (obviously). I have two or three now, so I'm safe. I managed to find a very long (29") washingmachine (no, dryer belt) belt that I will try to cut up and glue together if I run into trouble on that. But in the mean time, I keep an eye out for anything or anywhere that might have them for the correct price.

Hi Richard, Maybe you already know, but you'll need to layer the joint if you cut and splice a belt. The tensile strength is in the fibre core, the inner is one grade of rubber for grip (Quite flexible so it can compress at pulleys), the outer layer provides some robustness overall, and is a "stronger" and stiffer rubber compound, but with a designed amount of stretch to extend around the tensile layer (that shouldn't have much stretch) when going around pulleys. You'll need to use a rubber (Contact) adhesive, not superglue - as a superglue bond is brittle and will fatigue rapidly. Leather belts are quite practical, and can be sewn at the joint overlap. (I use belts that no longer fit my waist!). You can replace a flat belt with a toothed (Timing) belt of suitable size. As it will work almost as well as the flat belt, you may not notice any difference? Is this link any use?
https://www.motionco.co.uk/pulleys-belts-c-25.htmlThere are a few suppliers, but at what cost?
Cheers!
K

 

[Steamchick]

Hi K,

Re-reading this post, don't use the voltage regulator when testing !

Ah. but I did... as I wanted to see how the LED bulb preformed as well.
A few numbers: from the buck controller output:
Blue generator: with "12V. LED array".
~130rpm => ~6V
~190rpm => ~8.5V. = Flickering LEDs
~360rpm => 10.1V. = Constant LEDs
~965rpm => ~10.7V = quite bright LEDs

Red generator: with "12V. LED array".
~100rpm => ~8.5V. = Flickering LEDs
~190rpm => 10V. = Constant LEDs
~350rpm => ~11.5V = BRIGHT LEDs.

Combined generators: with "12V. LED array".
~190rpm => ~11.5V. = BRIGHT LEDs.
I may do some more measurement - as you suggest - when I get an engine mounted and can have more control over what I am doing. Messrs Heath and Robinson would laugh at how I have been working!

Using a 12V battery (from my drill) I got 12.2V = 0.37A drawn by the LED array.
Previously, using a 12V 21W bulb, without the Buck Controller: Red Gen = 7V AC. Blue gen = 5V AC. both at around 850~900 rpm.

Anyway, my conclusion is that I can use the combined gens to illuminate my preferred LED array, and need sufficient input to achieve 200rpm. generator speed.
Next I'll try engines and pulleys, to see which is best matched...
Thanks for your help. K

 

[BaronJ]

Hi K,

The data you have got is only valid for the regulator and that particular load. Doing the testing as I described will allow you to generate curves that will tell you exactly what power you have available and over what range of drive speeds.

You keep saying "Buck Controller". I think the device that you are using is simply a voltage regulator or switch mode power supply, in which case you do not have any data on its own internal consumption, which could easily be as much as 50% of the power available.

In any case you have something that works for you which is all good !

 

[RonW]

Oh, another one: "old royal oilfield" = More than 20 years old, Royal Enfield Motorcycle, renowned for their inability to retain all the oil inside the engine... - the space where they were parked often resembled an Oil-field" - a large black patch on the ground. Hence the play-on-words.
Old Gits like me understand such inane jargon...
Git is someone you wish would "git ouda here!" (Git = slang verb for Go away).

Enjoy!
Language is the lubricant of society.... - sometimes things squeak a bit!

Git. Short form of giddyup isn't it?
RonW

 

[Richard Hed]

Hi Richard, Maybe you already know, but you'll need to layer the joint if you cut and splice a belt. The tensile strength is in the fibre core, the inner is one grade of rubber for grip (Quite flexible so it can compress at pulleys), the outer layer provides some robustness overall, and is a "stronger" and stiffer rubber compound, but with a designed amount of stretch to extend around the tensile layer (that shouldn't have much stretch) when going around pulleys. You'll need to use a rubber (Contact) adhesive, not superglue - as a superglue bond is brittle and will fatigue rapidly. Leather belts are quite practical, and can be sewn at the joint overlap. (I use belts that no longer fit my waist!). You can replace a flat belt with a toothed (Timing) belt of suitable size. As it will work almost as well as the flat belt, you may not notice any difference? Is this link any use?
https://www.motionco.co.uk/pulleys-belts-c-25.htmlThere are a few suppliers, but at what cost?
Cheers!
K

Whoa! Leather! Didn't thimk of that. thanx. and Thanx for the rubber glue info and stuff about how belts work. Will try all of this. Am so tired of being ript off.

 

[perko7]

Whoa! Leather! Didn't thimk of that. thanx. and Thanx for the rubber glue info and stuff about how belts work. Will try all of this. Am so tired of being ript off.

FWIW I also use leather belts for one of my lathes. I join them with a scarf joint about 30mm long and standard PVA glue , clamped between two pieces of metal while setting. No stitching or other reinforcement of any kind. The first belt was already on the lathe when I got it but had to be shortened to fit my re-arranged drive set-up. It must have been at least 30 years old but still pliable. It eventually came apart but not at the join I made. The current belt was also made using leather belting that came with the lathe and would also be the same age as the previous one. It has been on the lathe for 3 years now and shows no sign of coming apart. I don't use a lot of tension on the belts (belt slip is my safety fuse) and always remove the tension when not in use.

 

[RonW]

Wish I could enjoy some of that Strawberry jam! - Yum! - Lucky you.

Devonshire cream teas at "sprockets" house this afternoon. Scones, strawberry jam and clotted cream.