PD: Primary Drive Make your own Generator

BigEd

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Dear Stu,
Please check your conversation mail. (Envelope at top right of screen.)
 

vibrac

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Stu I think you have it it was a bad new chain that stuffed my rollers as an aside I seem to recall that Reynolds at that time also had welded seam rollers something to do with the rise of triplex chains for car timing chains.
 

JustPlainBill0

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I came across an article discussing using a stepper motor as a generator: https://www.applied-motion.com/news/2015/06/using-step-motor-generator . It starts out innocently enough...somebody wanted to use a stepper motor to charge a 12 volt battery. It quickly "degenerated" into hi tech model building that left me scratching my head. But there may be something there that someone pretty technical who understands this stuff (Vic?) and wants to estimate output against motor RPM, could use to his advantage.
At a more plebian level, there's a pretty good YouTube video on the subject here: https://youtu.be/lAvCYuNxGS8
 

ray schriever

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If these are brushed ac motors I suspect the brushes are set in the neutral plane. If they are dc brushed motors with a nominated DOR then their brushes would be offset opposite to the DOR to counter for armature reaction. If they are reversible dc motors they would be neutral again. So, if set as a generature the motors armature reaction would be opposite to that of a motor. Without the offset as a generator, voltage and therefore current would not be optimal? Just saying
 

JustPlainBill0

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If these are brushed ac motors I suspect the brushes are set in the neutral plane. If they are dc brushed motors with a nominated DOR then their brushes would be offset opposite to the DOR to counter for armature reaction. If they are reversible dc motors they would be neutral again. So, if set as a generature the motors armature reaction would be opposite to that of a motor. Without the offset as a generator, voltage and therefore current would not be optimal? Just saying
Ray, I don't have an answer about brushes, but stepper motors are brushless and when used as "generators" (alternators) produce alternating current which has to be rectified (more magic) to become direct current as we need. To operate as motors, they most often use DC -- though some run on AC.
 
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Bill Thomas

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What could be nicer than one of these, It looks like it was made for the job, Sorry Norman, It was !.
Cheers Bill.
 

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timetraveller

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Thanks Bill. For those who are not sure, that is a Walkernator, developed by Dick Sherwin and myself. One thing that is going to emerge from the tests with motors being used as generators is whether there is going to be sufficient heat generated to cause troubles. Many car alternators contain a fan to keep it cool. The one illustrated does not but they do have quite large holes in their casing. It was intended for use on 2CV Citroens where it is mounted directly on to the exhaust manifold, about as hot a place as one could find. They have never given trouble but the new Nippon Denso ones now being used do have a fan built in. One thing to note in the various videos showing stepper motors used as generators is the very small amount of current being generator. The experiments currently underway with various motors are going to let us know whether this is a route worth exploring and as such I admire the effort being put in.
 

vibrac

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What could be nicer than one of these, It looks like it was made for the job, Sorry Norman, It was !.
Cheers Bill.
I agree Bill it fills the gap where the rear cylinder was on the twin its a nice functional piece of machinery I will say however it certainly looks better on a Comet than a twin and it copes with the variations in the Comet crankcase exterior variations that were produced over the years (in one of my installations I had to make a curved stud)
 

oexing

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Bill, you are a tiny bit ironic about good looks of a car alternator on a classic ??
Myself not very knowledgeable about stepper motors or brushless to this day I hooked up a small stepper motor to my lathe , set 2000 rpm and got up to 60 V DC from it on rectifiers - but no usable power when connected to a 6 V 35 W bulb and no more voltage showing. It is sort of a short with that bulb. So I don´t see much use of a stepper for generator, so instead better get a brushless servo motor like these in my photos below.
I got the big , longer type these days, was express shipping from China at € 40.- -they would not do snail mail. So it is € 90.- plus taxes.
The performance was very impressive from the three phase rectifier, while still waiting for the bike regulator to arrive :
14 V on a 60 W quartz bulb at 1360 rpm - 1090 at crank speed
14 V on a 100 W quartz bulb at 1480 rpm - 1180 at crank speed
14 V at 120 W bulbs at 1580 rpm - 1265 crank speed
I blew two quartz, a 60 W plus a 100 W connected - but not safely, so both destroyed by unreliable contact and overvoltage.
I can only later tell higher power readings with the regulator, limiting voltage to 14 V at high revs, so for the while we have to wait for the next shipping.
That is a lot more electric power than I need , I´ll have a big magneto anyway.
When you look at the massive 15 mm shaft, 14 mm at the pulley drive fit, you can figure out what it does as a motor. I don´t care the least what this type does in this role but am only interested in generated power. So this is a good tell-tale for what to expect from any motor as a likely generator. The smaller shorter brushless below has a 8mm shaft, quite powerful , see numbers at the start of this thread. The new type is 14 mm shaft and almost excessive for my needs. For judging the "load" on the dynamo sprocket: Contrary to some comments this cannot possibly be much as I could easily hold the motor in the lathe in the right hand while getting the revs from the reflex digi tachometer in left hand with 120 W load. After all, 200 W is just a quarter of a hp at best, negligible.
Cooling might be a factor to keep in mind, but then , I guess power will be well below 300 W anyway, so only part of this will go up in heat. As no electronics are inbuilt in the motor 100 degrees should be no factor - unlike in the regulators in typical car alternators. There you waist part of the generated electric power for sustaining the magnetic field in the rotor. With a permanent brushless this is done away but you turn some of the power into heat in the motor coils and the simple regulator. Well, you can´t have it all, a simple brushless motor - or a brushed alternator with regulated field supply. This does not worry me much looking at modern motorcycles with mainly brushless type permanent magnet alternators, millions of them on the road. Generators behind covers mounted on the engine. So an air cooled small brushless on top of the gearbox with some temperture conductive contact should be allright, the Altons with identical tech are proven, with lower power when ungeared I guess. And they operate in all sorts of bikes from the timing gear drives, having certainly an easier life there compared to the triplex chain/ESA drama.
The new motor was skimmed in the lathe for 68 mm o.d. because I had the cases already done for common 68 mm motors. When you look closely 68 mm is the absolute minimum diameter with it as the 3 mm threads of the long bolts just started to get exposed. So I made new bolts with 6 mm nuts which were made to be heads of the bolts . These were loctited onto 3 mm rods with threads at both ends. One of the heads has to be filed flat to the front flange so as to clear the engine case. The new front flange was extended for two ball bearings - 15/32/11 mm - and suitable for an o-ring fit in the engine case bore.
Conclusion : These China brushless motors look all the way like great alternatives to the very expensive Altons - for those who love to do some machine jobs on the lathe and mill. Once this is done you need no longer worry about expensive repairs or replacements as you can get low price spares from China any day and have all components exactly to your liking when doing the job yourself. So I am looking forward to reading your stories here with experiments and real road reports.

Vic

stepper motor test:
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new longer brushless :

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rear end extension - for ignition pickup ?

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front end 14 mm pulley shaft

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turned down 68 mm , shortened rear cap, front twin ball bearing flange extension:

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