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Faking the transmission is really a bizarre move, but actually having a multiple-gear transmission in an electric racecar is actually not a bad idea. Formula-E

Faking the transmission is really a bizarre move, but actually having a multiple-gear transmission in an electric racecar is actually not a bad idea. Formula-E cars have 5-speed sequential transmissions in order to maximize torque [1], and this may be coming to electric road cars as well [2]. [1]: https://www.reddit.com/r/FormulaE/comments/2gbika/why_do_formula_e_cars_have_a_five_speed_gearbox/ https://www.reddit.com/r/FormulaE/comments/2gbika/why_do_for... [2]: http://www.motor1.com/news/48231/bosch-says-evs-will-soon-get-multi-gear-automatic-transmissions http://www.motor1.com/news/48231/bosch-says-evs-will-soon-ge...

Animats 11y ago
Bosch makes transmissions. They're getting worried. Formula-E cars are required to use a specific McLauren motor.[1] The need for a gearbox may reflect its limitations. Formula-E rules also limit input current, so using huge amounts of electrical power for a few seconds of acceleration isn't permitted. In other words, they don't allow Tesla's "launch mode". Early Tesla models had a two-speed gearbox. That was a disaster. The shock of changing gears over such a wide range wore out the gearboxes rapidly. Electric locomotives have been transmissionless since the first GE locos. "You cannot strip the gears of a magnetic field", one of the early GE designers wrote. Some things just work better electrically. For a sense of this, here's part of the restoration of the biggest steam locomotive ever built, the Big Boy.[1] It sat at the Ponoma fairgrounds for half a century, and was then towed out and sent to the Union Pacific shops for a full restoration. It's being towed out by a standard sized modern AC Diesel-electric locomotive, which has more drawbar pull than the Big Boy. What's impressive is the precise control. The initial move is about one foot per minute, because they're pulling the old steam giant through a tight curve of temporary track. The Diesel-electric doing the pull has synchronous AC motors and solid state controls, and can apply huge torques smoothly at low speeds with no wheel slip. All the wheels are locked together by active control. You don't need a transmission to get low-end torque from an electric. [1] http://www.mclaren.com/appliedtechnologies/products/item/e-motor-120kw-130nm/ http://www.mclaren.com/appliedtechnologies/products/item/e-m... [2] https://www.youtube.com/watch?v=-Ji2aGJJAx8 https://www.youtube.com/watch?v=-Ji2aGJJAx8
- jacquesm 11y ago
  The radius of that track is insane.
  - Animats 11y ago
    It's kind of distorted by a telephoto lens, but yes. That was temporary track to get the loco from the parking lot of the Pomona Fairgrounds onto Metrolink commuter tracks. They'd done enough work on the Big Boy that it would roll on its own wheels at slow speed. UP actually cut the Metrolink rails, spliced that temporary spur in, got the Big Boy out, put in a retired Diesel for display, and restored the Metrolink tracks. On Metrolink track, they hauled the Big Boy to a connection with UP rails, then hauled it to UP's Coulton yard. There it got enough repairs for a long tow at a reasonable speed, with the lubrication systems working. It's now at Cheyenne, Wyoming, where it will be fully restored and converted to burning oil, then used for fan trips and PR. (Why did steam die out? Maintenance interval for the Big Boy - daily. Maintenance interval for the Diesel-electric towing it - 6 months.)
    - jacquesm 11y ago
      I watched the whole thing, thanks for the link. Recently I took a little trip with this little guy: http://www.hoornmuseumstad.nl/nw-24745-7-3474828/nieuws/vier_de_zomer_bij_de_museumstoomtram_hoorn-medemblik.html http://www.hoornmuseumstad.nl/nw-24745-7-3474828/nieuws/vier... Hard to imagine what it would be like to see that brute up close under power.

Animats 11y ago

Bosch makes transmissions. They're getting worried. Formula-E cars are required to use a specific McLauren motor.[1] The need for a gearbox may reflect its limitations. Formula-E rules also limit input current, so using huge amounts of electrical power for a few seconds of acceleration isn't permitted. In other words, they don't allow Tesla's "launch mode". Early Tesla models had a two-speed gearbox. That was a disaster. The shock of changing gears over such a wide range wore out the gearboxes rapidly. Electric locomotives have been transmissionless since the first GE locos. "You cannot strip the gears of a magnetic field", one of the early GE designers wrote. Some things just work better electrically. For a sense of this, here's part of the restoration of the biggest steam locomotive ever built, the Big Boy.[1] It sat at the Ponoma fairgrounds for half a century, and was then towed out and sent to the Union Pacific shops for a full restoration. It's being towed out by a standard sized modern AC Diesel-electric locomotive, which has more drawbar pull than the Big Boy. What's impressive is the precise control. The initial move is about one foot per minute, because they're pulling the old steam giant through a tight curve of temporary track. The Diesel-electric doing the pull has synchronous AC motors and solid state controls, and can apply huge torques smoothly at low speeds with no wheel slip. All the wheels are locked together by active control. You don't need a transmission to get low-end torque from an electric. [1] http://www.mclaren.com/appliedtechnologies/products/item/e-motor-120kw-130nm/ http://www.mclaren.com/appliedtechnologies/products/item/e-m... [2] https://www.youtube.com/watch?v=-Ji2aGJJAx8 https://www.youtube.com/watch?v=-Ji2aGJJAx8

jacquesm 11y ago
The radius of that track is insane.
- Animats 11y ago
  It's kind of distorted by a telephoto lens, but yes. That was temporary track to get the loco from the parking lot of the Pomona Fairgrounds onto Metrolink commuter tracks. They'd done enough work on the Big Boy that it would roll on its own wheels at slow speed. UP actually cut the Metrolink rails, spliced that temporary spur in, got the Big Boy out, put in a retired Diesel for display, and restored the Metrolink tracks. On Metrolink track, they hauled the Big Boy to a connection with UP rails, then hauled it to UP's Coulton yard. There it got enough repairs for a long tow at a reasonable speed, with the lubrication systems working. It's now at Cheyenne, Wyoming, where it will be fully restored and converted to burning oil, then used for fan trips and PR. (Why did steam die out? Maintenance interval for the Big Boy - daily. Maintenance interval for the Diesel-electric towing it - 6 months.)
  - jacquesm 11y ago
    I watched the whole thing, thanks for the link. Recently I took a little trip with this little guy: http://www.hoornmuseumstad.nl/nw-24745-7-3474828/nieuws/vier_de_zomer_bij_de_museumstoomtram_hoorn-medemblik.html http://www.hoornmuseumstad.nl/nw-24745-7-3474828/nieuws/vier... Hard to imagine what it would be like to see that brute up close under power.