Team Trev

10 responses so far ↓

• 

  Alessandro // 2010-02-07 at 08:07 | Reply

  Just curious,
  what’s the weight of the 25 kW DC electric motor?
  Isn’ t a 3phase AC electric motor lighter, more efficient and reliable, even less costly ?
  What about the life and the number of charge/discharge cycles of the lithium battery? Do you envisage to fully discharge it ?

  Good luck
  Alessandro (Pisa, Italy)

  • 

    teamtrev // 2010-02-08 at 18:06 | Reply

    Alessandro,

    The motor we used to drive from Darwin to Adelaide was a brushed DC motor, with a mass of about 40 kg. An AC induction motor would be lighter, more efficient and perhaps even cheaper, but requires a more complicated and more expensive controller.

    A permanent magnet brushless motor is smaller, lighter and more efficient again. We have recently replaced our entire rear end with the swing-arm from a Vectrix scooter. The swing-arm, motor, reduction gear, wheel and tyre have a mass of about 27 kg. The motor is a permanent magnet brushless motor. More efficient, more reliable, but more expensive.

    Our current (120 km range) lithium ion polymer battery has an estimated life of 250000 km. The new battery will be larger, and have an even longer life.

    We have designed the car so that we do not (often) have to discharge beyond 80%.

    Peter

• 

  Alessandro // 2010-02-08 at 21:45 | Reply

  Thanks for your response

  Correct if I wrong,
  but as far I know an induction motor is far lighter than ANY dc motor (besides the right arguments about expensive controllers and so on)

  For example, the Tesla Roadster 3-phase, 4-poles AC motor is only ~ 30 kg but for a power of about 250 HP, much better (x 5) than the power density you envisage. Moreover, it doesn’ t need any permanent magnet and thus rare earths resources that it’s very likely they run out in the short term

  Bye, Alessandro

• 

  teamtrev // 2010-02-09 at 12:47 | Reply

  You might be right about the mass of an induction motor. We should be comparing continuous power per mass, and it is not always easy to find the data. I was not able to find motor mass and continuous power figures on the Tesla web site. Brusa induction motors have continuous specific power of about 0.4–0.6 kW/kg. The Raser Technologies induction motor has 0.9 kW/kg. For permanent magnet machines, the UQM machines have continuous power density of 0.75–1.1 kW/kg. But there are large variations in specific power for both types of machine.

  Tesla has an article comparing permanent magnet motors and induction motors.

  Of course, Trev could use either type of motor. The difficulty for us was to find a low-mass, efficient motor that would operate at our chosen voltage (we were operating at 150 V, for historical reasons).

  Peter

• Small, beautiful, renewable energy cars « Antinuclear // 2010-02-10 at 08:44 | Reply

  [...] You can find contact details for Team Trev at teamtrev.com [...]

• 

  Peter Prohaska // 2010-03-19 at 23:49 | Reply

  dear sirs,
  up to 10 teams from around the world will take part at the Euro EV Race 2010 with their electric vehicles across Europe from October 3rd to 19th, 2010. We noticed your acitvity at the zero-race and thought that you might generally be interested in the Euro EV Race 2010.
  If you are, we send you further details.

  Best regards from europe

  Peter Prohaska
  Team Coordinator
  Euro EV Race 2010

  • 

    teamtrev // 2010-03-20 at 20:16 | Reply

    Zero Race will still be running at the time of the Euro EV Race, and there is only one Trev (at the moment). However, we will watch your race with interest.

    Peter

• 

  Fayaz Kadir // 2010-04-20 at 06:39 | Reply

  Hi, I am just going to answer one of Alexandro’s question..
  this was the post he wrote:
  “For example, the Tesla Roadster 3-phase, 4-poles AC motor is only ~ 30 kg but for a power of about 250 HP, much better (x 5) …”

  Hi Alexandro, Tesla does have a 250Hp motor, but you have to take in account that they are watercooled, and have a radiator to dissipate the heat from both the motor and the traction inverter. This lowers the overall power density.

  Then again, the inverters also weigh quite a considerable amount. Take in account of a Calmotor controller prototype GP450A,it weights 16kgs (just the controller, ignore the piping and the glycol solution flowing through it.)
  btw that inverter costs around the region of $8k, but then you add your tuning of your AC motor, which is another $3k, and then add another $1.5k for diagnostic tools. So we are looking at around $13kUSD, without even the motor.

  Now take in consideration of a Agni Motor, its Axial-brushed DC, yet upto 93% efficient. it weighs around 11 kgs, and produces 25Hp(1.7kW/kg) ( with proper clean airflow, and as much as 40Hp for around 40Seconds(tested on my electric Boat and Motorcycle).

  As mater of fact,Considering only AIR COOLED motors, DC motors pack more power if properly designed and they are simpler, and lower cost.

  Thats why you will see most EV conversions start with DC motor. Look at the White Zombie (Electric Car Dragster) that uses DC, not AC, or perm-mag

  But DC are not the most efficient. The work efficiently near No-load. Thus for any application using DC, Bigger the motor, the more efficient it will be during usage.
  But more comparative load, more is the loss.

  I hope that clear’s out the confusion.

  -Fayaz Kadir

• Trev: A two-seater renewable energy vehicle | Santa Barbara Electric Vehicle Association // 2010-05-27 at 05:22 | Reply

  [...] You can find contact details for Team Trev at teamtrev.com [...]

• 

  A milestone for the logistics team « Team Trev // 2010-07-01 at 14:02 | Reply

  [...] Contact us ← Back from Bibendum [...]