Re: [ElectricMotorcycles] Throw another Etek on the barbie
Hey Mike, Would you mind filling in some gaps that I dont know about on your build? I think I got something really close to a "guess"timation. gear ratio rear tire size new weight of bike and your weight (if your dont want to tell me I gonna say 215 :-P ) Sure thing... Gear Ratio: 1:4.2352941176 Rear Tire: 170/60 Bike Weight: 377 Mike Weight: 165 -- The Electric Motorcycle Portal http://www.electricmotorcycles.net/ Electric Motorcycle Listserv http://www.electricmotorcycles.net/listserv
Re: [ElectricMotorcycles] Throw another Etek on the barbie
Man, this parallels what I was thinking. Except I wanted to show it in a graph. I will post as soon as I get mike's info Andrew Wowk wrote: > Say you are pulling 200 amps with one etek running > at any voltage: > > 200 * .033 ohms (terminal resistance) = 6.6v * 200 = > 1320 watts in heat that > one etek must dissipate without frying. Luggage? GPS? Comic books? Check out fitting gifts for grads at Yahoo! Search http://search.yahoo.com/search?fr=oni_on_mail&p=graduation+gifts&cs=bz
Re: [ElectricMotorcycles] Throw another Etek on the barbie
Hey Mike, Would you mind filling in some gaps that I dont know about on your build? I think I got something really close to a "guess"timation. gear ratio rear tire size new weight of bike and your weight (if your dont want to tell me I gonna say 215 :-P ) I was trying to figure this out for dale when he burnt his Perm and asked for a why in the ADC vs Perm question, but I never got around to getting all the data and replying. Lyle --- Mike wrote: > So, anyone care to guestimate what temp one wants to > keep a spinning > etek under? Like Chris says, the spinning part is > really important. > I wasn't even going very fast when mine let go. > Maybe 20 mph - tops. > Moody friends. Drama queens. Your life? Nope! - their life, your story. Play Sims Stories at Yahoo! Games. http://sims.yahoo.com/
Re: [ElectricMotorcycles] Throw another Etek on the barbie
Jeff: Baffles me, the idea to overlook cooling air in the design of the motor...why not mae the housing of aluminum with cooling fins or just have fins in the existing frame The etek was probably extensively tested in its designed-for application. I bet if you stayed within the manufacturer specs the motor would run fine for an acceptable life. Whats not understood is that the 300 amp for 30 sec limit is probably starting at room temp while the motor is cool. This is an unrealistic spec for real world design. If you run it at 100 amps until the temperature stabilizes, than it may be out-of-spec to go over 100 amps without cooling down first. Chrisj: I wonder if the new brushless version has those copper clippys? My guess is no - I'll bet B&S has received lots of complaints and did what they could to make them go away. It shouldn't, as the PM magnets are always the rotating component in a brushless DC motor. Chris: Just took a look at Mike's pictures. I wonder if you could wrap the armature with a Kevlar band to take some of the load off the solder joints? Someone I talked to at Electric Vehicles USA mentioned doing that for racing I think. I'm sure either they or the guys at thunderstruck would know how. Jonathan: in a brushless motor the windings should be mechanically part of the casting and able to conduct heat away better. Quite a bit better to my understanding. The stator can get extremely hot very quickly in a conventional brushed motor design with high current. The casing temp is a poor indication of how hot the critical rotating buss bars get. Kind of like an electric stove heating element or a toaster, if you turn it on it'll heat up quickly, and also cool down pretty quick from the very high temps if you shut it off. I'll bet Mike's etek got much hotter than 160 internally. Jeff: I can control the heat build-up in the motor by very gradually applying throttle. If I spin the throttle to full most of the 200+ amps will turn into heat and I still won't get wheel spinning take-off anyway. Until WE find a nice small 2 speed trans, acceleration is going to be just less than a land speed record machine (okay not that bad) but when you gear for 60 MPH top the compromise in take-off is fairly significant Or, why not thrown on another etek? Half the resistance (with the motors wired in parallel) and you half the losses in heating, and each motor must dissipate 1/4 the energy in heat. Say you are pulling 200 amps with one etek running at any voltage: 200 * .033 ohms (terminal resistance) = 6.6v * 200 = 1320 watts in heat that one etek must dissipate without frying. Throw an etek into the mix: 200 * .0165 ohms = 3.3 * 200 = 660 watts in heat that is divided between two eteks, so each etek must dissipate 330 watts without frying. Darn, I guess its not magical that my duel eteks stay really cool even under very high loads. Additinally, because I'm wasting less in heat, I get less pack voltage drop when accelerating. And because the motors are heating up less, the terminal resistance does not rise much (meaning they run more efficiently). The PMG uses clips like the ETEK but I still see no evidence my motor is being over-amped... the PMG is actually rated for 72 volts the ETEK is rated for 48 volts. That might explain the price difference, I haven't heard of someone frying a PMG (yet). I have heard of one frying running in the wrong direction. I'd bet that the larger slots in the sides help keep the bars cooler than on those on the etek. Johnathan: Maybe I should rephrase... I haven'l blown up a motor or controller or anything yet You have yet to be initiated... Regards, Andrew
Re: [ElectricMotorcycles] Throw another Etek on the barbie
I have a brushless Etek but I haven't spun it up yet. I am still a n00b on these things but from the controller research I have done it seems to But aren't we all? It's not like you see electric motorcycles scooting all over the place. Maybe I should rephrase... I haven'l blown up a motor or controller or anything yet On a lighter subject. What 'big ticket' EV items have you guys blown up? Here's my list that I can remember off the top of my head: Artisian DC/DC Converter (they had the pins mis-labeled in the instructions) One controller One motor Four battery chargers Mike -- The Electric Motorcycle Portal http://www.electricmotorcycles.net/ Electric Motorcycle Listserv http://www.electricmotorcycles.net/listserv
Re: [ElectricMotorcycles] Throw another Etek on the barbie
Either will be dangerously hot. You were measuring the outside casting though and the heat is generated in the coils which I expect got quite a bit hotter at least for a short time. So, anyone care to guestimate what temp one wants to keep a spinning etek under? Like Chris says, the spinning part is really important. I wasn't even going very fast when mine let go. Maybe 20 mph - tops. I checked the temp within 3 minutes of the event on the outside of the case and it was 160 F. (I checked, it was indeed Fahrenheit.) I'm looking at some thermal switches by Airpax: http://www.airpax.net/site/sensing/bimetal/index.html http://www.airpax.net/site/utilities/eliterature/pdfs/Airpax_SCSF_6700_0607.pdf http://www.airpax.net/site/utilities/eliterature/pdfs/Airpax_SCSF_6600_0607.pdf http://www.airpax.net/site/utilities/eliterature/pdfs/Airpax_SCSF_6500_0607.pdf Here's what's percolating in my mind: Plan A) Have three switches set to trigger at 3 different temps. Two normally open and one normally closed. Switch A closes at X degrees. This turns a fan on. Switch B closes at X+ degrees. This turns a light on to warn of impending shutdown. Finally, switch C opens at X++ degrees. This is in series with the main contactor and shuts the power to the motor off but still allows the dc/dc converter to power the cooling fan. Plan B) Uses a Dallas Semiconductor DS18B20 (or similar) sending signals to your micro. The micro controls the fan and main contactor. Maxim has pretty wide selection of thermal switches, temp doodads and other hot/cold related things. I haven't had a chance to go over their site much yet: http://www.maxim-ic.com/products/sensors/ Mike -- The Electric Motorcycle Portal http://www.electricmotorcycles.net/ Electric Motorcycle Listserv http://www.electricmotorcycles.net/listserv
Re: [ElectricMotorcycles] Throw another Etek on the barbie
Mike wrote: I have a brushless Etek but I haven't spun it up yet. I am still a n00b on these things but from the controller research I have done it seems to But aren't we all? It's not like you see electric motorcycles scooting all over the place. Maybe I should rephrase... I haven'l blown up a motor or controller or anything yet -- Blog: http://volcano.newts.org
Re: [ElectricMotorcycles] Throw another Etek on the barbie
I have a brushless Etek but I haven't spun it up yet. I am still a n00b on these things but from the controller research I have done it seems to But aren't we all? It's not like you see electric motorcycles scooting all over the place. -- The Electric Motorcycle Portal http://www.electricmotorcycles.net/ Electric Motorcycle Listserv http://www.electricmotorcycles.net/listserv
Re: [ElectricMotorcycles] Throw another Etek on the barbie
Actually the PMG has slots on the brush side that allow shooting the laser right at the end 15% of the coils, so yes I might not be reading the inner coil, I sure am reading inner temps to some degree (pun intended). Bottomline is if I force a steady stream of air across the motor it will wick out a significant amount of heat and the air flow into the front of the fairing towards the back will wisk the hot air away from the bike internals. Future Plan: Temp sensor to turn off the fans when case temp goes below safe level. For now the fans will come on when the ignition key is turned on. Waiting on fans... man-o-man this is fun!! Jeff -Original Message- >From: Johnathan Vail <[EMAIL PROTECTED]> >Sent: Jul 18, 2007 10:26 AM >To: ElectricMotorcycles >Subject: Re: [ElectricMotorcycles] Throw another Etek on the barbie > > >On Wed, July 18, 2007 9:54 am, Mike wrote: >>>Did you mean 160F or C? I have read the latest temps after pushing >>>the PMG pretty heavily (200 down to >> >> Fahrenheit is what I'm pretty sure the thermo was set on but now >> you've got me wondering. Surely the solder that holds it all >> together can't melt at 160F? >> >> >>> 100 amps for some 20 seconds or so) and read 212F. I think the temp >>>sensor is a good idea, have one of the mini-eight fan assemblies on >>>the way. Found this pie-plate-looking thing at home depot that will >>>attach to the brush side of the motor and force cool air into the >>>motor and out of the shaft side of the > > >Either will be dangerously hot. You were measuring the outside casting >though and the heat is generated in the coils which I expect got quite a >bit hotter at least for a short time. > > >jv <- Hells Amperes Motorcycle Club > > >-- >Blog: http://volcano.newts.org > >
Re: [ElectricMotorcycles] Throw another Etek on the barbie
On Wed, July 18, 2007 11:15 am, Chris Tromley wrote: > I'm very heavily on Damon's side on this one. The Etek seems to be a > wonderful device, but it is very intolerant of operation outside its > design envelope. An EM leans on that envelope pretty hard. > > I wonder if the new brushless version has those copper clippys? My > guess is no - I'll bet B&S has received lots of complaints and did > what they could to make them go away. > I have a brushless Etek but I haven't spun it up yet. I am still a n00b on these things but from the controller research I have done it seems to me that the ratings for the brushless version are a lot more conservative. It may also just be slightly less powerful and capable. I haven't taken mine apart (~yet~) so I can't comment on the windings but in a brushless motor the windings should be mechanically part of the casting and able to conduct heat away better. jv < Hells Amperes Motorcycle Club -- Blog: http://volcano.newts.org
Re: [ElectricMotorcycles] Throw another Etek on the barbie
On 7/17/07, damon henry <[EMAIL PROTECTED]> wrote: I've got no ideas about your DC to DC, but this is why I always recommend the 6.7 inch series wound motors over Eteks. It's not that they can't do the job, but they are too easy to fry. Too many amps either undoes all the solder or demagnatizes the magnets. Yes they are small, and yes they are efficient, but the lack of thermal mass is a big part of the reason why they are easily destroyed. damon I'm very heavily on Damon's side on this one. The Etek seems to be a wonderful device, but it is very intolerant of operation outside its design envelope. An EM leans on that envelope pretty hard. I believe there's a design flaw in the Etek. Without having seen one up close I'm speculating a bit, but apparently there is a bunch of copper clippy bits on the periphery of the armature that are heavy because they have to carry big currents. They are held in place only by solder. Big mistake. You *never* use solder as a mechanical attachment method in a critical application where there are any significant forces involved. (Per numerous government studies on military electronics.) Centrifugal force at 1000s of rpm acting on chunks of copper is pretty significant. Further, those government studies found that the best way to get solder to fail is to put it through lots of low-level temperature cycles while under load. In other words, it's not necessarily the event you're in the middle of that makes it fail - you could have been setting the stage for failure for quite a long time. Wasn't there someone on this list who had one fail a short time into the first ride of the day? If I had an EM running an Etek I would waste no time in making sure it runs cool under *all* circumstances. Really cool. Run it hard, then put a thermocouple directly on those copper clippys. (I don't know what is an acceptable temperature, but cooler is better.) Keep making changes until the temperature under heavy use goes *way* down. If the case makes it difficult to get air where it's needed, I'd look into cutting the case. I wonder if the new brushless version has those copper clippys? My guess is no - I'll bet B&S has received lots of complaints and did what they could to make them go away. Chris P.S. Just took a look at Mike's pictures. I wonder if you could wrap the armature with a Kevlar band to take some of the load off the solder joints?
Re: [ElectricMotorcycles] Throw another Etek on the barbie
On Wed, July 18, 2007 9:54 am, Mike wrote: >>Did you mean 160F or C? I have read the latest temps after pushing >>the PMG pretty heavily (200 down to > > Fahrenheit is what I'm pretty sure the thermo was set on but now > you've got me wondering. Surely the solder that holds it all > together can't melt at 160F? > > >> 100 amps for some 20 seconds or so) and read 212F. I think the temp >>sensor is a good idea, have one of the mini-eight fan assemblies on >>the way. Found this pie-plate-looking thing at home depot that will >>attach to the brush side of the motor and force cool air into the >>motor and out of the shaft side of the Either will be dangerously hot. You were measuring the outside casting though and the heat is generated in the coils which I expect got quite a bit hotter at least for a short time. jv <- Hells Amperes Motorcycle Club -- Blog: http://volcano.newts.org
Re: [ElectricMotorcycles] Throw another Etek on the barbie
Did you mean 160F or C? I have read the latest temps after pushing the PMG pretty heavily (200 down to Fahrenheit is what I'm pretty sure the thermo was set on but now you've got me wondering. Surely the solder that holds it all together can't melt at 160F? 100 amps for some 20 seconds or so) and read 212F. I think the temp sensor is a good idea, have one of the mini-eight fan assemblies on the way. Found this pie-plate-looking thing at home depot that will attach to the brush side of the motor and force cool air into the motor and out of the shaft side of the Can you send us a picture of this pie plate gizmo? I think I'll order both the 8 fan assembly and a 'normal' fan for the next etek and experiment. Mike -- The Electric Motorcycle Portal http://www.electricmotorcycles.net/ Electric Motorcycle Listserv http://www.electricmotorcycles.net/listserv
Re: [ElectricMotorcycles] Throw another Etek on the barbie
Did you mean 160F or C? I have read the latest temps after pushing the PMG pretty heavily (200 down to 100 amps for some 20 seconds or so) and read 212F. I think the temp sensor is a good idea, have one of the mini-eight fan assemblies on the way. Found this pie-plate-looking thing at home depot that will attach to the brush side of the motor and force cool air into the motor and out of the shaft side of the motor. Baffles me, the idea to overlook cooling air in the design of the motor, also why not mae the housing of aluminum with cooling fins or just have fins in the existing frame. Silly really. Still thinking the pancake motor a great choice for two wheeled vehicle. Jeff VF500 Franken'ceptor (575 miles, one charger bit the dust, 60 mph - 18 mile range). -Original Message- >From: Mike <[EMAIL PROTECTED]> >Sent: Jul 17, 2007 9:07 PM >To: ElectricMotorcycles >Subject: Re: [ElectricMotorcycles] Throw another Etek on the barbie > >>Wow. Mike when you kill 'em, you kill 'em dead as a hammer. > >I remember my first year in college. I had an instructor who told >me, "If it's worth doing, it's worth doing right." He never did >anything half way. He's my hero to this day. Ha ha. > > >>separately excited motor (no field to excite). Methinks some current >>limiting/temperature sensing is in order before I add another dead >>Etek to the pile. > >Yeah. Figure that out right away will ya? I've got another etek in >the mail already. My very limited knowledge in matters such as this >is to toss a Dallas Semiconductor temp probe on the motor and a relay >on a cooling fan all bundled to em dash. > > >>Aluminum melts around 1600 F, so I doubt that the slag you see is >>aluminum. Solder goes liquid well below 500 F depending on the mix. >>It seems some form of ram/forced cooling is seriously in order for >>the Ezuki design. > >Oh, I know it's solder. I zapped the motor with an IR thermometer >just a couple of minutes after melt down and read 160 F if any one >was curious. > >Mike >-- > >The Electric Motorcycle Portal >http://www.electricmotorcycles.net/ > >Electric Motorcycle Listserv >http://www.electricmotorcycles.net/listserv >
Re: [ElectricMotorcycles] Throw another Etek on the barbie
I've got no ideas about your DC to DC, but this is why I always recommend the 6.7 inch series wound motors over Eteks. It's not that they can't do the job, but they are too easy to fry. Too many amps either undoes all the solder or demagnatizes the magnets. Yes they are small, and yes they are efficient, but the lack of thermal mass is a big part of the reason why they are easily destroyed. damon From: Mike <[EMAIL PROTECTED]> Reply-To: ElectricMotorcycles To: ElectricMotorcycles Subject: [ElectricMotorcycles] Throw another Etek on the barbie Date: Tue, 17 Jul 2007 21:19:51 -0400 Stick a fork in it. I think it's done. It was pretty spectacular and very, very smelly. I'd would have thought they used blue smoke in it like other electrical stuff but it was dark gray. How they get that much smoke into something so small is beyond me. Too many amps for too long is my initial diagnoses. It got too hot and the non-twerly bits that where soldered to the twerly bits got unsoldered. This turned them into little shards of hot bits falling onto the roadway. Apparently spinning something at high rpm with high temps is just as good at desoldering as braid. I need to spend more time at the autopsy table because the wire to the dc/dc converter is really what caused most of the smoke it turns out. That wire went from the main pack to the dc/dc to the system ground as it came out of the dc/dc. It's all toast. Every single millimeter of the wire burned off its insulation. I came around a turn and really hammered the throttle and the motor went. As I looked down I saw the dash light up like a christmas tree. So it looks like the motor died and in someway that killed the dc/dc? Anyone care to explain to me your theories of what happened? I'm not sure if I blew anything else up yet. Let's hope the controller and em dash are okay. Pictures: http://electricmotorcycles.net/modules/xcgal/thumbnails.php?album=1 Mike -- The Electric Motorcycle Portal http://www.electricmotorcycles.net/ Electric Motorcycle Listserv http://www.electricmotorcycles.net/listserv _ http://imagine-windowslive.com/hotmail/?locale=en-us&ocid=TXT_TAGHM_migration_HM_mini_pcmag_0507
Re: [ElectricMotorcycles] Throw another Etek on the barbie
Wow. Mike when you kill 'em, you kill 'em dead as a hammer. I remember my first year in college. I had an instructor who told me, "If it's worth doing, it's worth doing right." He never did anything half way. He's my hero to this day. Ha ha. separately excited motor (no field to excite). Methinks some current limiting/temperature sensing is in order before I add another dead Etek to the pile. Yeah. Figure that out right away will ya? I've got another etek in the mail already. My very limited knowledge in matters such as this is to toss a Dallas Semiconductor temp probe on the motor and a relay on a cooling fan all bundled to em dash. Aluminum melts around 1600 F, so I doubt that the slag you see is aluminum. Solder goes liquid well below 500 F depending on the mix. It seems some form of ram/forced cooling is seriously in order for the Ezuki design. Oh, I know it's solder. I zapped the motor with an IR thermometer just a couple of minutes after melt down and read 160 F if any one was curious. Mike -- The Electric Motorcycle Portal http://www.electricmotorcycles.net/ Electric Motorcycle Listserv http://www.electricmotorcycles.net/listserv
Re: [ElectricMotorcycles] Throw another Etek on the barbie
Wow. Mike when you kill 'em, you kill 'em dead as a hammer. One of the things on my list to do after this course on Electric Machines is over (next week is finals) is look over the Etek and analyse it more before employing it. A PM motor is considered a special case of a separately excited motor (no field to excite). Methinks some current limiting/temperature sensing is in order before I add another dead Etek to the pile. Aluminum melts around 1600 F, so I doubt that the slag you see is aluminum. Solder goes liquid well below 500 F depending on the mix. It seems some form of ram/forced cooling is seriously in order for the Ezuki design. By the way, a course in Electric Machines will tell you more than you ever wanted to know about how DC motors operateand AC motors, and transformers too. It is a hard course with moments of high interest and terrible realiztion that there is too much to learn about the world of electric machines. Here's a link to material about DC machines: http://www.ee.ryerson.ca/~courses/ele637/Lecture%20Notes/ELE637_Chapter3.pdf Doug in South Carolina - Original Message - From: "Mike" <[EMAIL PROTECTED]> To: "ElectricMotorcycles" Sent: Tuesday, July 17, 2007 9:19 PM Subject: [ElectricMotorcycles] Throw another Etek on the barbie Stick a fork in it. I think it's done.
