tag:blogger.com,1999:blog-4063450658421522356.post7467085988633233542..comments2024-03-09T04:13:55.185-06:00Comments on Open PRT specification project: 69> About That Angled Wheel Design...Danhttp://www.blogger.com/profile/16303568401426087509noreply@blogger.comBlogger10125tag:blogger.com,1999:blog-4063450658421522356.post-31084012305311512532020-03-24T02:36:10.786-05:002020-03-24T02:36:10.786-05:00Thanks a lot for sharing this amazing knowledge wi...Thanks a lot for sharing this amazing knowledge with us. This site is fantastic. I always find great knowledge from it.<br /><br /><a href="https://thegoodmarket.shop/collections/car-accessories" rel="nofollow">Car Wheel Parts</a>Anonymoushttps://www.blogger.com/profile/09155126770064042480noreply@blogger.comtag:blogger.com,1999:blog-4063450658421522356.post-76253283870836044382019-09-26T03:38:04.886-05:002019-09-26T03:38:04.886-05:00I have strong feelings on this issue Japanese used...I have strong feelings on this issue <a href="https://blauda.com/country_option/zimbabwe.html" rel="nofollow">Japanese used cars for sale in zambia</a><br />Erica Rulehttps://www.blogger.com/profile/13042814292680426962noreply@blogger.comtag:blogger.com,1999:blog-4063450658421522356.post-34299765673511524292019-04-15T02:13:09.473-05:002019-04-15T02:13:09.473-05:00thanks for sharing this informative blog Used Hond...thanks for sharing this informative blog <a href="https://www.sbtjapan.com/used-cars/honda/?model=hrv" rel="nofollow">Used Honda HRV Cars For Sale</a>RoseMarryhttps://www.blogger.com/profile/01939025997135486390noreply@blogger.comtag:blogger.com,1999:blog-4063450658421522356.post-23327153214103063512010-02-01T06:42:17.660-06:002010-02-01T06:42:17.660-06:00http://www.kinkisharyo.co.jp/eng/e_topphoto/e_phot...<a href="http://www.kinkisharyo.co.jp/eng/e_topphoto/e_photo_80.htm" rel="nofollow">http://www.kinkisharyo.co.jp/eng/e_topphoto/e_photo_80.htm</a><br /><br /><a href="http://home.inet-osaka.or.jp/~teraoka/old/tera98/ml98edit.htm" rel="nofollow">Osaka Subway Line No.7</a><br /><br />each LIM looks to have ~9sqft. of area facing the stator and produces ~135hp. the vehicles go up to ~40mph.<br /><br />T2k says, "<a href="http://web.archive.org/web/20030820101837/www.skywebexpress.com/1435_energy_use.shtml" rel="nofollow">The power will peak at about 20 kw per vehicle and will average about 4 kW per vehicle including air conditioning and heating.</a>"<br /><br />from p.5 of <a href="http://www.prtnz.com/component/option,com_docman/task,doc_download/gid,13/Itemid,57/" rel="nofollow">Transit Energy Use</a>, ~2kw of that would be Auxiliary Energy if there are 3 passengers. so the LIMs are probably each rated at ~9kw or ~12hp. for whatever it might be worth, the <a href="http://en.wikipedia.org/wiki/Smart_(automobile)#Technical_data" rel="nofollow">smart fortwo</a> weighs 1800lbs empty and is rated at 52kw.<br /><br />the idea of 4 LIMs was similar to your method in <a href="http://openprtspecs.blogspot.com/2009/04/linear-induction-motor-tractor-unit.html" rel="nofollow">post 26</a>, except horizontally and using 6 wheels in order to achieve articulation.<br /><br />as for the control system, as i understand it: the guideway is logically divided into segments, some long, others (e.g., merge zones or station zones) short. the zone controllers use the same code as the vehicle controllers to calculate where the vehicle should be by the next time its position is checked.<br /><br />along with local guideway alignment, line speed depends on local wind speed. basically, you'd go as fast as safely possible, except to facilitate merges. the main difference between Anderson's asynchronous and a synchronous system (e.g., ULTra) is that merge conflicts are resolved locally as the vehicles approach. vehicle routing can be revised by the central computer through fiber-optic comms with zone controllers. <a href="http://www.prtnz.com/component/option,com_docman/task,doc_download/gid,5/Itemid,57/" rel="nofollow">Control of PRT</a>, beginning on page 7.<br /><br />i think that routing intelligence could be improved and/or distributed later.cmfseattlenoreply@blogger.comtag:blogger.com,1999:blog-4063450658421522356.post-20506603581327439952010-01-30T12:38:25.121-06:002010-01-30T12:38:25.121-06:00The roller coaster aspect you refer to is all abou...The roller coaster aspect you refer to is all about being able to maneuver in close quarters, because a system that needs to be laid out like a mini freeway is only useful for the few routes that have such right-of-way is available. Making a cheap track can only go so far. The real cost might just be in the wrangling over real estate. <br /><br />The RPMs that bearings can handle is determined by how even and heavy the load and how large the shaft diameter. At 4000 rpm, they won’t wear out right away, but I’m not real comfortable with them lasting years either. I built a woodworking machine years ago with dual 1.5” shafts, (4 bearing units) @ 3500 rpm, and the first sign of slop and roughness was after only about, (I’m guessing) 1500 hrs., and within about that amount of time again, a second started to go. The machine, now in storage, never had a problem with the other two. Actually I attribute the failures to them being off-brand, more than anything else. There are also noise, vibration, and general complexity factors. <br /><br />I prefer to start a design with very high performance expectations and then dial it back. Otherwise you might end up with the PRT equivalent to a three-wheeled racecar. <br /><br />I believe all reasonably fast bottom supported PRT systems should be propelled by linear motors because of icy track issues. I can see no way out of it, save continuous, high-powered track defrosting. <br /><br />I am very surprised that Skyweb Express lists 60 mph as a top speed. That is quite an achievement for their design architecture. I would be curious as to if those numbers are really practical in the field, and what would be the maintenance schedules. <br /><br />LIM surface area (power) doubling might add 25% to speed. All of that is contingent on aerodynamics and the speed range involved. But doubling power doesn’t double speed, as I am sure you know. I guess it is theoretically possible to design LIMs that could be doubled up closely, although it might require a special, dual channel controller.. <br /><br />Do they allow individual speeds, or do bunches of podcars tend to stay bunched, and take all turns at “line-speed” no matter how sharp the turn? I admit to never really conclusively gleaning that info from Anderson’s discussions on “Asynchronous point-following” or whatever it is…Danhttps://www.blogger.com/profile/16303568401426087509noreply@blogger.comtag:blogger.com,1999:blog-4063450658421522356.post-13634254122409823692010-01-29T06:39:50.007-06:002010-01-29T06:39:50.007-06:00Marsden Burger on LIMs, weather, noise and reality...<a href="http://groups.google.com/group/transport-innovators/browse_thread/thread/d973aaa6fcbce38e/eabe6141ec532bac?lnk=gst&q=marsden#eabe6141ec532bac" rel="nofollow">Marsden Burger on LIMs, weather, noise and reality</a><br /><br />1800 inches/sec = 100mph. how fast do you need to go? how roller-coaster does it need to be? if you used 4 LIMs instead of 2, and used <a href="http://hamiltoncaster.com/CatalogPartDetails/tabid/561/PartId/S-528-UYB/Default.aspx" rel="nofollow">8-inch casters</a> (~4000rpm @ 100mph) instead of <a href="http://www.skyloop.org/cals/rebuttal/03-5-T2K-Vehicle-Wgt-Estimate-082301.pdf" rel="nofollow">4-inch casters</a>, would your requirements be met?<br /><br /><a href="http://web.archive.org/web/20030811202235/www.skywebexpress.com/150a_performance.shtml" rel="nofollow">Minimum Curve Radius<br /> <br />36 feet</a><br /><br /><a href="http://web.archive.org/web/20030811202749/www.skywebexpress.com/150d_guideway.shtml" rel="nofollow">http://web.archive.org/web/20030811202749/www.skywebexpress.com/150d_guideway.shtml</a><br /><br />"<a href="http://www.prtnz.com/content/view/55/1/" rel="nofollow">PRT need not have lower line speed. Line speed is an economic factor, not technical.</a>"<br /><br />"There must be sufficient tread on the tires and the running surface must be sufficiently rough to make the<br />coefficient of friction as high as practical." <a href="http://www.prtnz.com/index2.php?option=com_docman&task=doc_view&gid=10&Itemid=57" rel="nofollow">Safe Design, (Time Headway and the Linear Induction Motor), pp.5-7</a><br /><br />bottom line: the failure deceleration rate should not be greater than a following vehicle's emergency braking rate.<br /><br /><a href="http://advancedtransit.org/doc.aspx?id=1029" rel="nofollow">Transit Systems Theory</a>cmfseattlenoreply@blogger.comtag:blogger.com,1999:blog-4063450658421522356.post-15082052674541165782010-01-28T22:47:55.170-06:002010-01-28T22:47:55.170-06:00Dan the Blogger Responds -
I’m not sure what you...Dan the Blogger Responds - <br /><br />I’m not sure what you are driving at with comments 1 and especially 2, cmfseattle.<br />Behave? In what respect? As for the weather thing, you’re right, they are not immune to condensation, possibly even frozen. This would be quite easy to manage compared with continuing snow or ice accumulation, however. By the way, the running surfaces are rubber mounted, so the thermal mass is minimal. Therefore the running surface temperature will tend to follow the ambient temperature, inhibiting condensation. Why do I suspect you were referring to something else? Have I overlooked something? As for the headway speeds… <br /><br />It skids or it doesn’t, and not skidding is good enough, imho. I see no additional advantage to really, really, really not skidding. I think emergency, brick-wall stops would never happen, but to satisfy insurance companies and the like this should be done by clamping to the track anyway, even with linear, so to me traction is a manageable, if not minor, issue.<br /><br />If you can show me any way to match the combination of speed, turning and price performance I have been talking about with a linear system, I will be “all ears.” A great big (horizontal) turning radius is a deal killer for me because of all of the issues that result from inflexible routing options. It’s extremely hard to get ANY route through an approval process. Needing the space over corner properties is opening a Pandora’s box. A big vertical turning radius is somewhat better, but for me still requires a complete system redesign or custom LIMs. Anyway, It’s pretty hard to critique or try to improve upon proprietary systems whose details are trade secrets. I personally don’t see a practical way to do it. <br /><br />To those readers out there who don’t know, Linear Induction Motors are shaped like big blocks that must be held within about an 1/8th inch of a reactor plate which runs along the track. (closer is even better, efficiency-wise) It’s a bit like having a car that hangs so low it can’t even clear a cockroach. It’s going to want to scrape when you crest a hill. The more power you want, the bigger the block’s “almost” contacting surface must be and the more magnetic forces must presumably be held at bay. These inter-reacting surfaces are normally held apart by little wheels. Engineering all of this for highway speeds is a challenge. The required power, and therefore these surface areas, must increase geometrically compared to the resultant speed increase, with this effect becoming more and more pronounced the faster you want to go. In other words, what works great for lower speeds and fairly straight track becomes more and more cumbersome for curvy or fast applications. The concept of a motor with no moving parts sounds great at first, but for vehicular use it actually uses more parts than direct drive rotary motors mounted within the vehicles wheels. I favor the rotary option, but only because I have not currently seen or invented a practical solution to the problems outlined above.Danhttps://www.blogger.com/profile/16303568401426087509noreply@blogger.comtag:blogger.com,1999:blog-4063450658421522356.post-19072834425514283602010-01-27T07:21:26.087-06:002010-01-27T07:21:26.087-06:001) hanging systems are not immune from the weather...1) hanging systems are not immune from the weather.<br />2) suspended-vehicle guideways will behave more like simply-supported beams than like clamped beams.<br />3) cabinentaxi proved that linear electric motors can consistently perform brick-wall stops at 2.5-seconds headway, in icy conditions.cmfseattlenoreply@blogger.comtag:blogger.com,1999:blog-4063450658421522356.post-20268632343607003642010-01-24T19:38:25.082-06:002010-01-24T19:38:25.082-06:00The design doesn't require a "frog"....The design doesn't require a "frog". The guide wheels do, indeed, hold the bogie captive in whichever side of the track is engaged. The other side is just there to distribute the load and wear where convenient, and to keep out the weather. <br />As for the "variable coefficient of friction" as you call it, I just want to reiterate that complete traction between a dry wheel and a dry surface is pretty well assured, unless there are truly extraordinary forces at work, which a good design should eliminate.<br />Anderson first creates a design which is susceptible to ice induced skidding and then offers the only logical solution to his own design shortcoming. He never mentions that hanging systems don't have a weather problem, and uses the most rudimentary mechanical brakes as examples of "stste of the art". No ABS. No Magnetic braking.Danhttps://www.blogger.com/profile/16303568401426087509noreply@blogger.comtag:blogger.com,1999:blog-4063450658421522356.post-64773164670418891262010-01-24T16:13:30.154-06:002010-01-24T16:13:30.154-06:00have you worked out the frog design? are the steer...have you worked out the <a href="http://en.wikipedia.org/wiki/Railroad_turnout#Frog_.28common_crossing.29" rel="nofollow">frog</a> design? are the steering guide wheels capable of supporting the vehicle?<br /><br />my other concern is your mention of varying the coefficient of friction along the guideway. because you can't rely on this to be constant, wouldn't you need every passing vehicle to test it somehow, so that the control system would be able to function safely? if you haven't already, read anderson's <a href="http://www.prtinternational.com/cms/articles/technical-papers/doc_download/11-overcoming-headway-limitations-in-personal-rapid-transit-systems" rel="nofollow">Overcoming Headway Limitations</a>, specifically pp.7-8.cmfseattlenoreply@blogger.com