| Author | Message | ||
     Hildstrom |
I developed a short to ground on my way home from work on Friday. A solder joint was pinched under the case cable clamp because I routed the wires too close to the screw.   The good news is that the discoloration does not indicate a failure of the J-B Weld; it is from oil deposits on the surface. Have a look where I lightly sanded it. The original epoxy was blackened throughout.  I ground the heck out of the sharp ribs around this area. Now I can route the wires through the center of the case cable clamp where they should be.  As usual, there are more photos and detail on my page. A thermocouple and amplifier are en route. I already have an Arduino and a few thermistors I plan on using to make a data logger. At minimum, I want to log stator temperature (thermocouple), regulator temperature (thermistor), and ambient air temperature (thermistor). | ||
| Timebandit |
Sorry to hear that you had an early failure.  After all of your work, that had to be really frustrating. I'm interested in how you're planning on mounting the thermocouple. I was thinking that ifyou mounted it radially (tangential to the wraps) you'd tend to minimize interference. Are you thinking about embedding the sensor in another layer of JB-Weld? Have you given any thought to embedding more than one sensor? I was thinking that it would be interesting to locate one at the bottom of the stator (6 o'clock) and one top/forward (2 o'clock as you're looking at the stator in the case cover). I think those are the cool and hot points, respectively. I was also wondering how well balanced your modded rotor is at high RPM, and if you had it professionally rebalanced or not. Great work! Thanks for sharing. | ||
| Timebandit |
Another idea -- just wondering if you did an oil change when you did your stator replacement, and if you did, did you notice any color change in your oil after your first 200 miles? FYI, I did an oil change with Mobil1 15W50 about 250 miles before I had to drop the oil for a rotor swap. I was surprised that the Mobil1 had been discolored from it's normal amber color to a VERY dark brown / black after only 250 miles. That oil has to be getting REALLY HOT to undergo that sort of change in such short mileage. For reference, none of my other vehicles do that to the Mobil1, and they've all been using the same lot of Mobil1 for over a decade. My oil-cooled BMW boxers never discolor Mobil1 like that -- it stays amber throughout the entire change interval. My air-cooled HD Evo does discolor it, but it takes a pretty long time to darken. In comparison, the 1125 darkens Mobil1 REALLY FAST. I'm thinking the stator has to be getting really effing hot. So when you say that the JB-Weld was discolored after only 200 miles, that doesn't surprise me a bit. Just for reference, Mobil1 is failure rated to 400*F. I have no idea how hot the oil has to get before it darkens, but I get the impression that the 1125 is running really hot. It would be very interesting to know how hot the stator is really getting. Of course, another possibility is that it's not the oil that's darkening due to heat -- it's possible that the the oil is acting as a solvent and that something else is breaking down and contaminating the oil. It would be interesting to know if other oils blacken as fast as the M1 seems to blacken. | ||
| Hildstrom |
Oldog, Timebandit: Thanks for the RTD suggestion. I had not heard of them before. Most/all of them are constructed using coils of wire, which does not seem like the best choice for this application given the proximity to alternating magnetic fields. I have used thermocouples before, so that's what I chose. Timebandit: Frustrating, yes, but solvable. With all of the hours I have into this already, I'm not going to give up now.  I'm going to J-B Weld the thermocouple between the bases of the two darkest poles near the taped stator leads. There is not much air/oil flow there, so it should record the highest possible temperatures on the stator without rewinding. The leads will be twisted together as much as possible to eliminate interference. That should also be a relatively low magnetic field area. I thought about doing two sensors, but only the hottest area matters to me at the moment. I would probably do two or three sensors if I were switching to the oil-squirting rotor. The balance of the rotor is not dependent on RPM. I did not have it professionally balanced. The rotor should still be fairly well balanced because the holes were spaced evenly, but I don't know for sure because I did not check it. I think you'd be able to balance the rotor yourself on a nice wheel balancing stand with the right size shaft/cones. | ||
| Hildstrom |
Timebandit: I don't really want to turn this into an oil thread, but the blackness of an oil does not necessarily indicate a problem and heat is not the only possible contributor. If you are running rich, unburned carbon may get past the rings and into the oil. Are you running an EBR ECM or tuned ECM? Also, the 1125 has a wet clutch and the two air-cooled bikes you mentioned do not (at least not wet with engine oil). Clutch debris from our VA-slipper clutches ends up in the oil. If you are at all worried about it, I suggest doing an oil analysis for $33. It certainly made me feel better. | ||
| Reepicheep |
Why thermocouples in the stator instead of thermistors? Are you thinking it will be too hot for a thermistor? | ||
| Hildstrom |
Repicheep: Yes. I want to accurately measure at least 500F or 260C just in case. The highest ones on Digikey are 300C, but that does not provide much headroom or margin. A thermocouple will be able to measure well above the failure point of the insulation and epoxy I chose. | ||
| Dannybuell |
Hildstrom ~ Congratulations! YOU are becoming the resident scholar for ROTAX stators. | ||
| Timebandit |
"Most/all of them are constructed using coils of wire, which does not seem like the best choice for this application given the proximity to alternating magnetic fields." it turns out that it's the opposite of what you'd expect -- the reason that they are coiled is to minimize/cancel out the inductive interference caused by close proximity to the alternating magnetic fields. in theory, the dual coils would be better than a thermocouple for precisely this reason. that's why RTDs are designed the way they are -- to minimize interference in embedded stator applications. | ||
| Hildstrom |
Dannybuell: Thanks, but this is not exactly why I bought it. Timebandit: RTD Dual coils, like a RH coil on top of a LH coil or a RH coil next to a LH coil? I see how that would cancel out any magnetic field effects and I definitely did not think of that before. I think the thin film type would be the worst type for interference, but it still may be more immune to interference than a thermocouple because of the higher voltages involved. I found this pdf with some good tips, since I already purchased the thermocouple. | ||
| Timebandit |
That's a helpful article -- it's got good tips on how to deal with the 3 types of noise you'll need to worry about. I'm really interested in hearing how your experiments turn out, using a series regulator with a modified "stock" (non-oiling) rotor. It would be even more interesting if you still have the shunt reg, and you could compare the numbers between series and shunt regulation paragidms. What have you decided to use as a the calibration standard? (I'm assuming that you plan on plotting a calibration curve for the thermocouple before logging the experimental data on the bike.) | ||
| Reepicheep |
What, no ice block in the tail section?  http://www.omega.com/ppt/pptsc.asp?ref=TRCIII-A (That is the technology we used for our thermocouple's when I was working at the big jet engine factory... Another reason why I like thermistors ) | ||
| Hildstrom |
Yeah, it would be interesting to measure the stator temperature with the stock VR and stock rotor, but I'm not willing to risk that with my rewound one. For calibration, I'll probably use boiling deionized water and some averaged readings from my toaster oven. The amplifier chip I'm using does compensation and direct digital conversion, so it should be very close right out of the box. If not, I'll use the offsets to adjust the logged data. | ||
| Ironman2 |
About to toss the 1125r out on the curb for free. VR or stator giving up on me, clutch locking up. My son said he has a friend able to fix it. Curb looking better. | ||
| Dannybuell |
Dibs!! My 96S1 had more problems in its first 2 years than my CR has had in its first 2 years. Once I sorted the S1 out it became and is very reliable with 96K fairly hard miles. The S1 is on her third locally rebuilt top end. The CR gets more Amsoil almost 3.4 quarts. There are two active threads where ground wires are mentioned for various bike ailments. A year ago there was a thread about is a ground wire going from regulator to battery. I did that. My automotive and electrically smart friends tell me you can't have enough grounds. My first stator went at 2,000 miles with harness replacement from day one. The replacement is doing OK at 17,000 miles. When the time comes the EBR oil jet rotor and whoever is doing Badweb stators when the time comes. | ||
| Hildstrom |
Thermocouple installed and briefly tested! Interference does not seem to be a problem. There is more detail on my page. I can't wait to finish the logger and get riding.      | ||
| Reepicheep |
nice! | ||
| Sekalilgai |
ditto! looking forward to your results! | ||
| Squish |
Dannybuell, Are you running a high level of oil to ensure the stator is less likely to be starved for oil? After learning about the thermal-related stator failure issues on the Buell 1125s, I keep my 2009 1125R oil level at the top end of the allowable range on the oil dip stick. John K. | ||
| Hildstrom |
Squish: I agree it is a good idea to keep the oil topped up. However, the stator does not sit in an oil bath. As long as there is oil pressure (no low oil pressure light), the stator will get the same amount of oil dripping down from the bearings regardless of oil level. | ||
| Dannybuell |
Squish ~ Yes, exactly. Hildstrom ~ IDK, we have all been told that oil goes down that part of the crank(?) and feeds the new rotor jet. I suspect that this pressurized oil passage sprayed oil onto the cover where it drained from there. Call me superstitious, my air/oil cooled experience tells me that more oil implies greater cooling potential. | ||
| Hildstrom |
I finished the logger last night. I rode in to work today and I'll capture the log this evening to make sure it is working properly. Then I'll log as much as possible this week and report some numbers.  | ||
| Hildstrom |
I went for an 80-minute test ride last night; almost all of it was below 5000rpm. Here are the results:  | ||
| Reepicheep |
Very cool! What the heck happened at 165 minutes? Why the sudden drop? | ||
| Hildstrom |
I was doing 80 in a 70 on loop 1604 and then 70 in a 65 on I10 for about 15 minutes of continuous highway in 6th gear. Not weaving, just going with the flow. I know; it would be great to also log coolant temperature, oil temperature, rpm, and speed. | ||
| Reepicheep |
Do you have the harness kludge installed? Maybe that triggered and dropped a leg. 280 degrees F... that's pretty toasty! | ||
| Oldog |
Nice job I figured that you had improved air flow, as the air temp is steady, and the reg temps drop, also the batt volts are up and steady the batt volt disturbance at about 150 is interesting.. 4000 rpm in 6th is 68 mph indicated on my '08 | ||
| Timebandit |
Very interesting! This is a great first set of data. By themselves, the numbers are hard for me to interpret though. Those temps look like they're lower than you'd get from a stock system because you're using a series regulator. I'd be willing to bet that with the shunt regulator, the temp curve would be a LOT higher. What would be most interesting to know is how many amps you're pulling out of that stator to produce that temperature. You are using a series reg after all, and it's load (and stator heat) is going to be dependent on your actual current draw. I don't think you've mentioned this -- at least I didnt' see it -- what kind of electrical system load are you putting on the bike? IS it a stock bike, with stock lights, no electrical accessories? High beams on or off? Knowing how many amps you're pulling out of the stator would really help to put that temperature curve into perspective. By any chance do you still have a working shunt regulator? It would be most helpful if you could perform a controlled experiment by swapping regulators to define comparison curves for shunt vs. series regulator with the stock rotor. I don't have the stock rotor any more -- I have the 1190RS (oiling) rotor, and it would be interesting to compare the effects of the oiling vs. OEM rotor with the shunt reg. | ||
| Dannybuell |
I like the idea for a shunt v.s. series regulator test. The arguments have been made for series regulators. A graph comparing shunt v.s. series regulators would be the ultimate summary statement for us non-electrical engineer types. | ||
| Hildstrom |
First of all, thanks for all of the suggestions, questions, and kind words. Reepicheep: No harness. 280<460 so I'm happy so far. Oldog: Stopped at a light for several minutes and voltage dropped when both fans kicked on. Notice how that matches the peak in regulator temperature. Timebandit: Stock bike, low beams the entire time. I still have the FH012AA shunt regulator for emergencies. I'm not willing to test it for fear of needlessly damaging my hard work. Keep in mind that I drilled air cooling holes in the rotor in addition to switching to a series regulator. I'm sure that has an effect too. Danybuell: The summary graphs in this experiment are great, but stator temperature was not measured. Supplement that with these thermal images and I don't feel the need to repeat it. I'm more interested in figuring out if my rewind is going to survive with my other modifications than in accurately measuring the conditions that led to my original stator failure. I do not feel there is much to be gained by testing with a shunt regulator, harness, or OEM rotor. I will definitely test the oil-jet rotor if I think my current setup is not going to survive and I'll test it next week if someone else buys. |
