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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Rick G on January 30, 2012, 07:36:02 AM
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I have heard that if you change the winding configuration of a 32 amp Alternator from Star to Delta you get an increase in the rating up to about 43 Amp.
Looking for info about this but cant find anything.
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Why go to all that trouble. Just get yourself the bigger alt and be done with it. They are available, just ask Drake.
Changing the configuration of the windings is no easy task if not impossible depending on the physical build of the winding assy.
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FYI, Here is where the upgrade is sold:
http://www.kbikeparts.com/50a_alt/50a_alt.htm (http://www.kbikeparts.com/50a_alt/50a_alt.htm)
$150.
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Why go to all that trouble. Just get yourself the bigger alt and be done with it. They are available, just ask frankenduck.
Changing the configuration of the windings is no easy task if not impossible depending on the physical build of the winding assy.
Thanks but I am aware that our Psychotic Waterfoul friend has them but getting it to Australia is not a cheap exercise and the 50 Amp ones here are not readily available. I can get the stator rewound for about $120 but thought I would investigate the configuration thing before anything else was done.
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Why go to all that trouble. Just get yourself the bigger alt and be done with it. They are available, just ask frankenduck.
Changing the configuration of the windings is no easy task if not impossible depending on the physical build of the winding assy.
Thanks but I am aware that our Psychotic Waterfoul friend has them but getting it to Australia is not a cheap exercise and the 50 Amp ones here are not readily available. I can get the stator rewound for about $120 but thought I would investigate the configuration thing before anything else was done.
USPS medium Flat rate box is ~ 50 dollars
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It is true that the power output of the alternator could theoretically be increased by rewinding the armature from wye to delta. The relationship between line and phase current in a delta configuration is IL = 1.732 * IP. In theory, a 33A Wye-connected three phase alternator rebuilt to delta configuration could produce 57A. But, I think there are other components on the alternator, such as rectifiers and regulator, would have to be changed as well to match the increased current not to mention larger gauge wire for the alternator windings. Furthermore, there are external connection differences between the 33A Bosch alternator for K100 and the K1100's 50A cousin. You'd have to provide a beefier binding post type output connector; the 33A unit only has a wimpy spade connector. The output cable on the 50A unit connects directly to the battery positive; on the 33A unit it routes through the starting relay. There are sufficient barriers to "clean install" that I'd consider a used 50A unit over a rebuilt 33A unit IMO.
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Thanks Rob that is what I was looking for. So in theory yes but in practice not too practical.
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The 50 amp ones are easily rebuildable. I did mine a while back, before I installed my used one. I didn't replace the slip rings, as they were fine, but they are replaceable.
http://www.motobrick.com/index.php/topic,788.0.html (http://www.motobrick.com/index.php/topic,788.0.html)
You could also look to shipping over the parts that differentiate the BMW alternator from a cheap VW/bosch one. Most likely the pulley side, and the bushing cup.
If Duck could chime in with some part #'s off of the 50 amp alternators, I could figure out what is needed.
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When upgrading from a 32a to 50a alternator on a K75, is it necessary to switch out the driving dog or just the clutch housing (cup) and rubber mountings (monkey nuts)
EuroMotoElectrics recommends a new driving dog on their site (http://www.euromotoelectrics.com/Alternator-K-R-Oilhead-BMW-ALT1020EDL-p/bmw-alt1020edl.htm), but when I spoke with them on the phone they could not confirm. The OEM fiches have the same Driving Dog part # 12311460304 but list it separately for "up to 7/1993" and "from 7/1993" as if they were different parts.
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Rick G just curious where in OZ are you.
Regards Martin.
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Rick G just curious where in OZ are you.
Regards Martin.
Stanthorpe, Queensland......he isn't active here anymore, sign up at the K100Forum if you want to connect.
Tim, you need only the cup....as the 32 and 50A has different shafts.
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Thanks Inge Stanthorpe Qld coldest place in Queensland, I believe it even snowed there. I definitely wouldn't be going for a visit in winter, I don't possess snow shoes :hehehe.
Regards Martin
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Tim, you need only the cup....as the 32 and 50A has different shafts.
Thanks, Inge!
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Removed the 32a alternator. Awaiting delivery of the 50a EnduraLast from EuroMotoElectircs (http://www.euromotoelectrics.com/Alternator-K-R-Oilhead-BMW-ALT1020EDL-p/bmw-alt1020edl.htm). It's "USPS Out for Delivery".
The brushes in my 32a were short and in need of replacing. I had replaced the entire voltage regulator w/ brushes and new monkey nuts 50k miles ago. The rotor spins smooth and free. Rubber bushings / monkey nuts are still in great shape. Drive dog is in good shape and can't be moved by hand.
Is it smart to add a heavier gauge wire from the alternator to the battery?
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Tim, I doubt you need a heavier wire from the alternator to the battery. The distance is so short that even at full output you wouldn't notice any additional voltage drop. I would just take a close look at the terminals on the wire. If they show any signs of corrosion between the conductors in the wire and the metal of the connector I would consider replacing the wire. If not, spend your time and money somewhere else.
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I've been wondering how long those alternator drive rubbers last but with 50k on those it seems they last a while
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When Duck was selling his 50A alternator upgrade kit, he included a heavier gauge wire as part of the package. You'd wire it directly from the alternator output to the battery +ve pole and abandon the 33A stock wire. On my K75 with 50A alternator, I've Duck's replacement wire plus an aftermarket 4GA ground wire. Maybe it's overkill but my electrics have been very reliable.
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Thanks, Robert. I've got a heavier cable to install.
I had some problems trying to install the EnDuraLast alternator from EME. I finally removed the cup and nut and tried fitting the alternator onto the bike again and it just wouldn't snug up. After a while I finally figured out that the mounting surface of the EnDuraLast alternator is not properly cut. There's too much metal near one of the mounting screw holes. The product image on their site is correct, just not the one they sent me. Also note that the screw hole diameter is larger on the EnDuraLast, although I don't think that will cause a misalignment problem.
I'm tempted to grind off the metal myself but I'll try to practice patience.
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Tim, be careful that the alternator fitment is correct. I blew a bearing in my intermediate housing when I installed my 50A because it captured the drive dog; it wasn't fun. Ensure the offset between the mounting flange and the top of the drive cup. That measurement should be 56.5mm.
(https://lh3.googleusercontent.com/-9OmNik9PnBI/TfUJvfuAlNI/AAAAAAAABVg/c75xCg-DtEI/s640/IMG_9208_sm.jpg)
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Thanks, Robert. I saw your old post a few days ago while doing research, so that offset measurement was the first thing I checked yesterday when I couldn't get the alternator to fit. Both alternators with cups measure the same.
Props to EME for replying to my Sunday morning email today within an hour. John Rayski replied and told me I could return and exchange the alternator or simply grind the relief cutout myself which is what they do at EME. Looks like I'll be firing up the grinding wheel.
John also said "...the bolt hole issue are non-relevant and do and will work, as this will cause NOT a misalignment problem ."
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I ground down the mounting surface so the alternator would fit. Taped over the alternator's vents to minimize metal dust getting inside while grinding.
Bike's all back together and runs smooth. Looking forward to a test ride tomorrow.
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After upgrading to the 50a alternator the bike is idling lower than usual, even after the bike has been ridden for an hour. It's gone from 1100rpm to 800rpm. But then sometimes at a stop light (or whatever) it will idle at 1000rpm.
Is it harder for the engine to turn the 50a alternator than the 32a alternator?
Do the bike's electronics recognize the new alternator and treat it different than the old alternator?
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All things being equal .... battery state, electrical load it should not require additional HP to drive it. The only condition where it would load the engine more is right after starting to bring the battery back up to nominal at a faster rate.
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If you remember, one of my symptoms of binding was a lower idle. Maybe you can test for binding of the drive dog by mounting the alternator with washers to raise it away slightly. If the idle speed returns to normal, you need to adjust the depth of the cup.
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I checked for binding by inserting the alternator without the rubber bushings and it fit the mount points easily. Then I unscrewed the cup nut most of the way and inserted the alternator again and it fit easily. The I added the monkey nuts, lubed them up, and the whole assembly slipped up snug easily by hand. There was never any resistance or need to snug up the alternator using the mounting screws.
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Hm, ok. Just a thought.
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I wonder if the blue wire has anything to do with it. I thought I read somewhere that this alternator outputs a slightly higher voltage than OEM to satisfy the newer AGM battery.
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When I put a 50 amp Kbike alternator in mine no difference noted.
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According to MAX, the 50A alternator weighs ~50% greater than the 30A. That may account for need for higher revs to run it. Why the idle wanders is another matter. Maybe it won't if the idle is set higher at the outset.
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I've been doing a lot of alternator readin' and learnin' lately.
It seems that once the bike starts sucking power from the alternator, resistance created by the alternator's magnetic field makes it harder for the engine to turn the alternator's rotor. I didn't know that.
I also read that the Enduralast alternators apparently output more wattage at lower RMP's (http://bmwmotorcycletech.info/AftrMrktAlt.htm) than the Bosch's. I need to call EME and run this by them though. They don't have any alternator specs published on their site.
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In a care when you kick on the AC and other electrical devices you can hear the engine rev to compensate for the load
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Basic physics .... to get energy out you need to put energy in. A lot of systems don't apply field current until the engine is running so it is easier to start. Motor/generator sets for example.
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Just discovered my battery light in the instrument panel was dead. Not sure for how long. Guess that means my alternator hasn't been getting excited.
Installed four fresh bulbs in the instrument panel. Too wet to go riding today though.
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Rode about 100 miles yesterday without trouble. The idle remained low when stopped (about 850rpm). When I got home I kept the motor running, hooked up the Carbtune and prepared to increase the idle a little. Well, for some reason before I adjusted anything the engine had settled into a 1000rpm idle. Grrrrrr. I bumped it up to about 1100rpm by adjusting the brass idle adjustment screw on each throttle body.
Received an emailed reply from EME today:
The old original Bosch 32 amp alternator was designed in the early 1980's; the rotor and stator windings not very compact,
and the air gap between the both of these components was quite large by today's manufacturing standards of modern alternators.
The later model alternator 50 amp and 60 amp alternators were designed in the mid-1990's-
both alternators are much more robust and technologically advanced-
both have much more copper electrical windings in both the rotor and stator
and
a tighter tolerance airgap between the rotor and stator .
Also a much more sophisticated electronic voltage regulator and rectifier.
What this all means is that the 50 a and 60 a units produce a much stronger electrical magnetic field at lower engine speed / alternator speed rotation;
this creates more current at idle engine speed and thru out the amperage current output curve ,
In other words, your new alternator is producing more current and sooner than the old unit.
We include both alternator test specification output sheets with numeric amperage values
and
test bench output curves to demonstrate the difference for comparative purposes.
So from what you are describing is correct -
the alternator is working correctly;
Since the alternator is producing a magnetic field / creating current at lower engine speed this will create a "drag" on the engine.
producing current and maintaining battery voltage at lower engine RPMs,
(as compared to the anemic old design) .
Bottom line;
A 50-60 amp alternator will require more engine horsepower than a 32 amp alternator.
EME also said that "Euro MotoElectrics ships the 60 amp alternator for both types, so you actually have a 60 amp alternator."
According to the attached spec sheet the alternator starts working at about 1200rpm. I'm assuming that's RPM's on the driving dog, not engine RPM. Anybody know what the RPM ratio is between the engine and alternator driving dog is?
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Anybody know what the RPM ratio is between the engine and alternator driving dog is?
It would appear that the K75 driveshaft has roughly 58 teeth and the output shaft to the alternator has about 40 teeth. With this roughly 1.5:1 gear ratio, the alternator's RPM is roughly 50% faster than the engine's RPM. (Right?)
According to the EME docs, the 32A alternator when spinning at 1500rpm (1000 engine rpm @ idle) outputs 0 amps. The 60A EnduraLast alternator is pumping out 30 amps at that same speed. That would certainly account for some engine efficiency.
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This new alternator has created an interesting idle adjustment predicament.
Back story: I figured that with the newly installed fuel injectors I ought to balance the throttle bodies today. (I removed the three brass idle adjust screws and cleaned them and their sockets up with Q-tips and brake cleaner. Put a little drop of oil on the O-rings. Replaced them one turn and a half from bottoming out.) Connected the Carbtune and began to adjust like I've done dozens of times in the past.
With the 32a alternator I've always set the idle at ~ 1100 rpm. No problem. With that 32a alternator the bike runs solely off the battery at that rpm, and probably any rpm up to about ~ 1400rpm.
With the Duralast 50a alternator, the bike seems to switch between drawing power from the battery and alternator at around 800 - 900 rpm. (Note the chart in the 12/25 post above.) With my battery meter I can see the switch between 12v and 14v happen when the rpm hits that threshold. Since 750 rpm is too low to reliably idle, the idle must be adjusted within an rpm range where the bike is running off the 50a alternator. So if I set the idle at 1000 rpm and a minute later the bike's fan starts up and stresses the alternator, engine rpm decreases with the new alternator load, perhaps down a couple hundred rpm to the point where the bike switches back to the battery for DC power and the alternator's load on the engine is released. Then the idle rpm increases since the alternator has turned itself off, ... and then the alternator starts up again, Do you see where this is going? Basically, it seems necessary to set the idle at about 1400rpm in order to allow for DC load changes without stalling the bike. Wacky.
Am I missing something?
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It is asserted that this alternator creates more power at less revs than the older model so the activation of the bike's fan shouldn't have such a great effect on it, should it? Maybe there's a defect with the fan or its circuit that's creating the problem?
From a cold start, it idles ok ±900 rpm and idles ok when riding until the fan is activated?
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Tim put a meter on the fan and see how much it draws.
Regards Martin
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I dunno... :dunno I'm not learned about alternators. Just trying to figure this crap out.
According to the EME data sheets, both alternators have a "Turn On Speed" of about 1200 rpm (that's alternator RPM) which is about 800 engine rpm. According to some reading (http://www.powermastermotorsports.com/faq-alternators_a.html#2), once an alternator is turned on or excited, it remains turned on until the engine comes to a compete stop. So what I said before about power switching between the battery and alternator is apparently hog wash. It's also possible I was reading the 32a EME data sheet graph incorrectly. It looks like a 200th generation photocopy.
My fan motor is just a couple of years old.
What I noticed was that, after an hour-long ride, I parked the bike but kept it running, hooked up the CarbTune and attempted to balance the TB's and set the idle. But every time the fan kicked-in briefly the engine RPM would drop and the battery meter would read ~ 12v. When the fan stopped the engine RPM increased and the battery meter reads ~ 14v. (This is an LED meter, so not exact values.)
I never experienced any weirdness like this with the 32a alternator.
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Are you able to set the engine idle and balance the TBs at ~1000 rpm or does the fan cycling always interfere, Tim? It seems strange to me that with temperature between the forties and fifties out there your fan cycles briefly within ten minutes after idling. My bike's fan takes longer than that to kick in at 50ºF. Maybe it's just a cold-blooded machine.
With the correct amount of coolant, a functioning fan, a functioning water pump and a fully functioning thermostat, this is what happens? If that's so and it were my bike, I'd disconnect the fan motor, finish the tune-up, reconnect the fan and see if I liked the idle on both sides of the fan cycle. Have you done that?
EME would be on speed dial, of course, and each step of the procedure would be followed by anapana sati.
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I'm also thinking it could have a defective voltage regulator but I'm out of my depth at this point.
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I'll try again tomorrow, and I'll put a real meter on the battery and see what's going on.
Maybe my temp sensor (http://www.seatrider.org/techntips/k75%20starting%20problem.htm) is kaput.
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... It seems strange to me that with temperature between the forties and fifties out there your fan cycles briefly within ten minutes after idling. My bike's fan takes longer than that to kick in at 50ºF. Maybe it's just a cold-blooded machine.
You're right, Laitch.
I discovered today that my idle fuel mixture was very rich after recently upgrading to the osidetiger 4-hole fuel injectors a few hundred miles ago. I've just fixed the mixture and balance the TB's. That ought to cool things down. The idle seems more controlled now. Got a busy week coming up so won't have a chance to mess around more until next weekend.