Development of DOHC Alternator Conversions Stopped

Posted: Fri Dec 02, 2016 2:21 pm

After expending thousands of dollars in design, research, components, engineering, machining, balancing, etc., I've hit what seems to be an un-solvable problem with the alternator conversions and have decided to stop development for the time being.

What I'm experiencing is an energy overload of the stator (regardless of brand) and without being cooled, will overheat, burn and fail. It's happened just after installation at the soonest or can happen after 500 miles of testing.

Since the permanent magnet rotor is ALWAYS "ON", whenever it spins, it will make electricity. The regulator/rectifier will stop the flow from entering the electrical system to prevent overcharging but, the spinning rotor continues to make power. And like an ignition coil that is energized (key on) without the engine running, will heat up and fail, the same thing happens here.
The PM rotor and stator that were chosen are from a 2002ish GSXR 600 where these components are "cooled" by running in engine oil. On our DOHC 4's, these are in a confined cavity without airflow or oil. So, the stator heats up and fails after the battery is charged to capacity.
Also, I've calculated that the GSXR with: cooling fan, ECU, fuel pump, injectors, ignition and lighting is using up most of the energy and only requires a small amount of cooling to keep everything working as intended. On our bikes, we have only the ignition and lighting to dis-charge all this energy after the battery is re-energized from starting the bike.

I can solve the problem by sealing the alternator cavity, tapping into the oil galley within it, fill the cavity with engine oil (like the GSXR) then provide a drain back into the motor. However, I can't rely on the end user/installer to do this easily and without issues.

I've solved all of the mechanical issues but, until a solution can be found to the heat/cooling issue, I'm not moving forward.

If any of you think you might have an answer, I'm all ears.

Posted: Fri Dec 02, 2016 2:55 pm

i'm no sparky so apologise for suggesting something daft - - but I do recall a thing called a "ballast resistor" that was used in old points system to prevent over cooking the coils - but isn't it a Rolling Eyes

, the Honda cooks the igniters in an oil bath they don't like and keeps the alternator dry when it likes to be wet
hope you do find a solution and get some just reward for the effort put it to help us all

Posted: Fri Dec 02, 2016 4:34 pm

Hi, since cooking a couple of rotors on long fast runs, I have been thinking about cooling the cavity with fresh air through a couple of lengths of maybe 15mm tube
1. Fresh air in via tube with small filter hidden under seat area
2. Hot air out via second tube onto metal pipe plumbed into exhaust just before silencer with the end facing "backwards" so that the exhaust flow creates a small vacuum and draws the hot air out of the rotor cavity. (think something similar has been done for venting crankcase)
No idea if it would cool enough but maybe.. I'm probably going to give it a shot next spring anyway. I'm currently using 1 rotor per year so why not?

Posted: Fri Dec 02, 2016 5:40 pm

Hi, sorry to hear about the time and money spent. Perhaps a way to turn it on and off, as with a centrifugal clutch that would engage at a certain rpm.

Twinstar Joined: Oct 27, 2013 Posts: 52 Location: germany

Hello,
is it possible to use the low pressure oilpumpe side for cooling the alternator?
From oilcooler to alternator cover (front) and from the back side to the oil pan.
But I think this will only work with a complete new alternator cover.
Regards,
Daniel

Posted: Fri Dec 02, 2016 10:31 pm

cbx_daniel wrote:

Hello,
is it possible to use the low pressure oilpumpe side for cooling the alternator?
From oilcooler to alternator cover (front) and from the back side to the oil pan.
But I think this will only work with a complete new alternator cover.
Regards,
Daniel

Daniel,
Oil cooling can be done in one method or another but, I need to provide a kit that's simple enough for almost anyone to install. If you read some of the tech questions here, some of these owners don't know which cylinder is #1 or how to diagnose and repair a simple turn signal inop problem.

The other issue (I now believe) is that the GSXR rotor/stator makes too much power for our bikes. In that, the GSXR alternator is about 20 amps output. The bike consumes about 16 to 18 amps running everything on that bike. So, it only has to dissipate 2 to 4 amps. Whereas our bikes (after the battery is recharged after starting) only consumes about 8 amps running. That leaves us with about 12 amps in excess that is constantly being produced with nowhere to go and nothing to cool it.

For myself, I might do that but, it's easier to just maintain the stock components than to go through all that trouble.

Posted: Fri Dec 02, 2016 11:40 pm

The main problem as I see it is you're taking a stator that's designed to be run in oil out of it's cooling medium, and putting it in a hotter dry environment than it was designed to work in, so the black goo is overheating.

MGW in Japan makes a PM alternator that runs in the dry alternator area on these bikes, presumably without this kind of problem. I wonder what they use for a stator?

Posted: Fri Dec 02, 2016 11:46 pm

nlrashia wrote:

... since cooking a couple of rotors on long fast runs ...

I've run lots of long fast runs without cooking rotors, once I finally got a good one. The problem is finding a good one.

Not all rewound rotors will survive long, they aren't created equal, and used rotors are a self-explanatory minefield of weak and ancient parts.

Posted: Fri Dec 02, 2016 11:57 pm

JR,

How do these guys do it? Reads like they did what you are trying to do..

http://translate.googleusercontent.com/translate_c?depth=1&hl=en&rurl=translate.google.com&sl=auto&tl=en&u=http://www.ne.jp/asahi/metalgearworks/website/shouhinitiran/cb750f_generator/cb750f_generator_1.html&usg=ALkJrhiVeGONHU4m861U3ZzL_vurgKQOxA

Posted: Sat Dec 03, 2016 12:48 am

Hmmm...

114,000 Yen = $1,004.45. But no shipping outside of Japan.

Posted: Sat Dec 03, 2016 12:52 am

Hmmm...

114,000 Yen = $1,004.45. But no shipping outside of Japan.

Posted: Sat Dec 03, 2016 1:22 am

MyCBF wrote:

Hmmm...

114,000 Yen = $1,004.45. But no shipping outside of Japan.

That's why one uses a buying service like Rinkya.

Posted: Sat Dec 03, 2016 2:29 am

BlueThunder wrote:

MyCBF wrote:

Hmmm...

114,000 Yen = $1,004.45. But no shipping outside of Japan.

That's why one uses a buying service like Rinkya.

Nope, theyt would add about 15% to the cost and you have to play shipping.

Get it from Webike for the best price and free shipping:

http://japan.webike.net/products/9726717.html

Posted: Sat Dec 03, 2016 3:20 am

JR, they are fitting an alternator to the Chang Jangs now off some Chinese small bike and that runs dry and they are not having any problems. I can get the measurements if you want. They have only just started supplying the kit in the last year or so. The Changs had the same wound/spinning rotor problems before

Posted: Sat Dec 03, 2016 3:25 am

How about a thin centrifuge type fan on the inside (nearest the cases) with some openings/slots in the cover that will allow/promote the assisted air flow to draw though the unit.

Captain

Posted: Sat Dec 03, 2016 1:13 pm

or you need to dumb down your stator

Is there something off another system that would work? Other than tons of wrecked bikes for cores, Is there anything special about the GSXR stator.

It would be a LOT of work, but could you short out a few turns on each windings to reduce the output/waste energy? At that point you might as well strip the core and rewind. But, to test your theory of "just to much excess energy", might be worth a try.

BTW Congratulations you have exceeded the motor heads 1st law of power:
If some is good,
more is better,
and to much is just right.

PM me about some magnetic analysis if you think it might help

afterthought edit:
rewinding cores could make having a few output options available, the guy that only wants enough energy to run the bike, to the guy with heated grips and gear . . .

Posted: Sun Dec 04, 2016 12:24 am

BlueThunder wrote:

JR,

How do these guys do it? Reads like they did what you are trying to do..

http://translate.googleusercontent.com/translate_c?depth=1&hl=en&rurl=translate.google.com&sl=auto&tl=en&u=http://www.ne.jp/asahi/metalgearworks/website/shouhinitiran/cb750f_generator/cb750f_generator_1.html&usg=ALkJrhiVeGONHU4m861U3ZzL_vurgKQOxA

What exactly am I looking at here?
I recognise the alternator cover, with stator; there is also the reg/rec and a fitting kit.
I'm guessing that the other thing like a dough ring mould with holes in the bottom must be the rotor.
According to the Webike photos, these two kits are the same. So this is a narrower profile alternator kit with a modern style stator.
I guess the stator fits into the inside the dough-ring mould rotor?

Our rotor is an electro-magnet, isn't it?
Moving a magnet past a coil induces current in the coil, basic generator stuff.
How does this rotor work, cos I can't see the magnet(s)?
This isn't my field, I'm a truck driver. The photos aren't clear enough to get a really good look at the thing. So there is probably some detail I'm not seeing which would answer my question.
All I can see is a machined steel cup with holes in the bottom and a hollow post in the middle to go over the crank.
Is there something else that I haven't seen even if it's in clear view, because I don't understand what I'm looking at?

Posted: Sun Dec 04, 2016 12:53 am

Simon wrote:

What exactly am I looking at here?

That's the MGW (metal gear works) alternator I mentioned before. It's been available in Japan for almost 10 years now.

I wrote:

MGW in Japan makes a PM alternator that runs in the dry alternator area on these bikes, presumably without this kind of problem. ...

Simon wrote:

I'm guessing that the other thing like a dough ring mould with holes in the bottom must be the rotor.

Yes, the "dough ring mould" is the permanent magnet/rotor that's attached to the crankshaft, and spins around the stator poles. The stationary stator sits inside the dough ring, but not touching.

The stator is in the cover on the inside like the stock stator, just a different shape and design.

Posted: Sun Dec 04, 2016 2:37 am

Simon, the steel cup with holes in it is the magnet

Posted: Sun Dec 04, 2016 5:02 am

JR, I can't email you but you have a number of pm's

Posted: Sun Dec 04, 2016 4:38 pm

I’ll put it all out here in the hopes you can understand all the issues:

For me, the DOHC alternator conversion project started as an offshoot of my CBX alternator conversions noting that several of my customers had charging issues on the fours and so did I as many folks do on our beloved vintage Honda’s. The immediate benefits are no brushes, rotors that won’t fail and reduced right side width of the motor.

I saw the MGW kit and figured I could do something like that (with a different design) locally for my small group of DOHC friends and perhaps go larger if successful. I also saw a posting where a fellow in England did the machining for the adapter plate in his home shop and also supplied some rudimentary dimensions. That’s all I needed to get me started. I improved the plate design and commissioned 3 plates to be CNC’d while I searched for the other components. All of this is “backburner” for me between all the other projects I do in my shop so, it’s taken me almost 2 years to pull this all together, starting slow, purchasing components, machining, fitting, testing, making revisions, etc., to where I eventually had a complete system to test on my own bike.

I had about 200 trouble free miles on my bike when I put together a second test mule for a friend but immediately had stator issues within 20 miles. I then purchased what I considered to be the best stator in the business and reinstalled the system on bike #2. Bike #1 is still accumulating trouble free miles when bike #2 failed again. Several folks suggested I try a MOSFET rectifier regulator. I purchased a Shindengen brand unit (best on the market), installed it on bike #2 with a new stator and balanced rotor.
At this time I’m also moving ahead on the other components of the system. The rotors are slightly out of balance and that creates handlebar buzz. Our local hot rod shop can balance them but, they needed to make a fixture to attach them to, in order to spin them up, done. I commissioned a redesign of the outer plate to include cooling fins (can’t hurt), purchased billet slugs of 6061T6 to machine 10. Additionally, there were bulk purchases of sealed fuse holders, custom made crank bolts, a case of stators, rotors and a handful of misc. items.

On the last good weather day for riding, my buddy and I took our bikes for a long test ride. Within 40 miles his stator was smoked, again. My bike was still operating OK with a cheap r/r and new stator. However, by the time we returned to the shop (over 400 miles total of testing) my stator was fried too.

Let’s stop the presses and really dig into this overheating issue.

MGW is doing their kits without any cooling and I don’t know how. Consider that the GSXR 600 components normally operate/cooled in oil (260 watts, about 18.5 amps). That bike uses about 85% to 90% of the energy produced ALL THE TIME (ECU, fuel pump, injectors, ignition, radiator fan and the normal lighting) and Suzuki still elected to cool the assembly in oil. Our bikes, using the same components only use about 20% of the energy produced and the rest needs to be dealt with because the permanent magnet rotor can’t be turned off. BTW, the GSXR components were initially selected for the physical size of the rotor and its taper matches the DOHC crankshaft.

All of the rectifier/regulators I tested whether they were cheap or expensive (no data available I can find on internal design) worked any different than the others (MGW uses a rectifier I can’t identify by their photos alone). One rectifier I purchased might have done the job but, it was so huge there was no place to mount it and still have some airflow around it. Scrap that idea.

Fans and clutches are out to of the question as well. There’s hardly enough room for the wiring. Fans seem to be OK for automotive style electro-magnet rotors that turn on and off. But, permanent magnet rotors can’t be turned off so, they’re always making electricity. Many motorcycle manufacturers cool the stator with engine oil which seems to be the preferred medium.

The best idea I’ve heard thus far is to decrease the output of the stator (less windings). But, 2 things: 1. MGW appears to be using the same stator construction I’m using and 2. I believe this would need to be custom made/wound. Would need to be sourced and priced.

BTW, the fellow in England never finished or tested his conversion.

If any of you have purchased and used the MGW kit, I’d like to hear from you. If you have a potential solution to this issue, drop me an email.

Posted: Sun Dec 04, 2016 4:53 pm

What's wrong with just using the lucas 3-phase stator and podtronics reg/rectifier like they sell at cycle-x? I've been using it on my bike and it seems to work pretty well.

Posted: Sun Dec 04, 2016 8:54 pm

I don't understand what the electrical engineering design that you described is doing, but Kawasaki ZZR 1200's have a 45 amp alternator that CG1000 owners grab on ebay as soon as they come up reasonably priced.
The early Kawasaki CG1000's have a alternator putting out 29 amp, so they prefer the 45 amp to supply.enough juice for all their heated gear, gloves, vest, socks, and so on a motorcycle that's not running fuel injection but carburetors like the ZZR1200. It has fuel pumps and electric fans for the radiator, but where's all that unused amperage going?
Is the ECU on Kawasaki's bikes doing anything to help? They must know something about dumping unused amperage, JMO.

Posted: Sun Dec 04, 2016 9:08 pm

CBX-tras wrote:

Since the permanent magnet rotor is ALWAYS "ON", whenever it spins, it will make electricity. The regulator/rectifier will stop the flow from entering the electrical system to prevent overcharging but, the spinning rotor continues to make power.

Why can't you just shunt that electricity to a devise to use up the extra power? ..., say, like a hot plate Wink

........anything small and using the extra current. Seems like an electrical engineer problem maybe.

Good Luck!

Posted: Sun Dec 04, 2016 10:37 pm

Grumpy32 wrote:

CBX-tras wrote:

Since the permanent magnet rotor is ALWAYS "ON", whenever it spins, it will make electricity. The regulator/rectifier will stop the flow from entering the electrical system to prevent overcharging but, the spinning rotor continues to make power.

Why can't you just shunt that electricity to a devise to use up the extra power? ..., say, like a hot plate Wink

........anything small and using the extra current. Seems like an electrical engineer problem maybe.

Good Luck!

After seeing the Cycle-X unit, I'm getting the feeling this was all for nothing.

Posted: Sun Dec 04, 2016 10:41 pm

cb1187 wrote:

I don't understand what the electrical engineering design that you described is doing, but Kawasaki ZZR 1200's have a 45 amp alternator that CG1000 owners grab on ebay as soon as they come up reasonably priced.
The early Kawasaki CG1000's have a alternator putting out 29 amp, so they prefer the 45 amp to supply.enough juice for all their heated gear, gloves, vest, socks, and so on a motorcycle that's not running fuel injection but carburetors like the ZZR1200. It has fuel pumps and electric fans for the radiator, but where's all that unused amperage going?
Is the ECU on Kawasaki's bikes doing anything to help? They must know something about dumping unused amperage, JMO.

This is the Kawasaki alternator (I think you're referring to) with the adapter plate to fit a CBX that I made. An entirely different unit and not adaptable to the DOHC 4s.

Posted: Sun Dec 04, 2016 10:58 pm

Quote:

After seeing the Cycle-X unit, I'm getting the feeling this was all for nothing.

I wonder what the maximum output of the Cycle-X alternator is? I can't find a spec for it on their website.

Posted: Wed Jan 04, 2017 5:54 pm

recently picked up a post on another forum that refer's to using the GSXR alternator on the GSX1100 (your GS1100) - comments about blowing a regulator but otherwise no reporting of frying windings - not really of any use other than to support your premise that the lack of oil cooling being a key cause - as the only real difference between the engines and the general elec power demand is the GS is wet

Posted: Wed Jan 04, 2017 6:52 pm

Genesound it's a Lucas three phase alternator. Here is what I found.

Genuine Lucas high output 3-phase alternator, complete package deal. Includes rotor, 14.5 Amp RM24 stator and PME 250 watt regulator/rectifier. This alternator has superior low RPM performance compared to our single phase option. Suitable for electronic and points ignitions and will power modern lighting. Simple way to convert to 12 volts. 3-phase alternators are ideal for slow revving engines and for thse who perfer to keep engine speeds as low as possible. The suprior low speed output of this 3-phase alternator means the battery will remain charged and the lights bright.

When comparing prices please note this is a Genuine Lucas alternator NOT pattern!

14.5 amp, genuine Lucas 3 phase stator & 74 mm rotor.
Superior low RPM output compared to the RM23.
Solid state PME 250 watt regulator/rectifier
Is able to run batterless if needed

http://www.rexs-speedshop.com/epages/es143131.sf/en_GB/?ObjectPath=/Shops/es143131/Products/ALT-SET-2

Posted: Wed Jan 04, 2017 11:06 pm

smoojee wrote:

When comparing prices please note this is a Genuine Lucas alternator NOT pattern!

The Prince of Darkness must be proud.