Would an electric car motor use ac or dc current?

If electric cars are to be mass produced what type of motor?

10 Answers

  • ProTon
    Lv 5
    1 decade ago
    Favorite Answer

    Electric cars can use AC or DC motors... If the motor is a DC motor, then it may run on anything from 96 to 192 volts, if it is an AC motor, then it probably is a three-phase AC motor running at 240 volts AC with a 300 volt battery pack. DC installations tend to be simpler and less expensive.

  • 1 decade ago

    AC all the way. The EV's made in the 1990's all used AC motors. In production, DC is dead.


    AC vector drive uses an incredible simple motor with 1 moving part, but it needs a very complex controller simply to work at all. Something has to make the magnetic fields rotate inside the motor, and this is done with six big thyristors in the controller. Expensive. And then it has to have very complex software. Once that's done, it can do everything people want - reverse, regen, and climb hills without a transmission.

    A DC motor is very complex, because there's a mechanical drum switch called a "commutator" which makes the magnetic fields rotate inside the motor (well, kinda.) The commutator is high maintenance. Because it's mechanical, it only needs one thyristor. BUT-- it can't reverse, regen or climb hills without a lot of extra stuff, and that makes more complications, and cost.

    Given the cost of silicon electronics today (and it's constantly falling), AC is absolutely the way to go, because it puts all the complexity in silicon and software. Silicon gets cheaper every year and software duplicates for free.

    Let's talk about each of the features.

    * Electric reverse. In a DC motor, you need a mechanical switch group to reverse the polarity of the field circuit. (or you can use 4 thyristors.) AC vector control just "does this in software".

    * Regnerative brake. In an AC motor, this is software. In a DC motor, regen requires putting the motor electrically in reverse, so see "reverse" above. Plus you need one more thyristor.

    * Wide power-band (so you can both climb hills and cruise on freeway, without a transmission): AC vector control: you guessed it, software :) DC motors can do it one of two ways. #1, use two motors and switch them between series and parallel. (three more thyristors.) Or #2, SepEx (seprately excited) which adds only one small thyristor.

    SepEx is really cool. It's a DC motor, but it uses a separate thyristor to control the field winding. The field winding is wound with thinner wire, so it draws much less current, so every thyristor that handles field current can be smaller. That means you only need one big thyristor (for the armature) and the rest are small/cheap, including the revers/regen circuits. Still, not cheap enough to beat AC vector drive. AC is still the way to go. But if you were homebrewing, SepEx would be really fun to play with.

    Source(s): Mechanical department at an electric railway museum. We have mostly series-wound DC motors, and one car with SepEx (the Boeing-Vertol LRV).
  • 1 decade ago

    DC Motor.

    while technically you can use either, a DC motor is better in this type of application for a couple of reasons:

    DC Motors approach infinite torque as their speed approaches 0 RPM giving them a better ability to move off the starting line. You can also use this to gear them more efficiently.

    AC is in the home instead of DC because it transmits across power lines better. The distance you can transport voltaic energy using DC is ridiculously short, plus high voltages transmit long distances better and AC can be converted easier through transformers. In Motor theory AC has an advantage that through a brushless motor is up to 30% more efficient than a DC motor and has a much higher RPM limit. This comes at the cost of extremely expensive inverter electronics and ESC's.

    For mass production the cheap DC motor would win out in a capitalist economy.

  • Anonymous
    5 years ago

    Today, AC induction motors are better for almost all applications, as you can use a VFD, variable frequency drive to supply the motor with the proper frequency and voltage for the desired load and speed. And an electric auto can afford the complexity of the VFD. For a school project, a DC motor would be better. .

  • How do you think about the answers? You can sign in to vote the answer.
  • Anonymous
    1 decade ago

    Electric current is either AC - alternate current like in your home, or DC - direct current, like from the batteries themselves. Both have been used successfully in electric vehicles. AC has to have an inverter converter to get usable energy from batteries. In other words getting AC from DC batteries. IT would also take a different motor to run the vehicle. Your choice.


  • 1 decade ago

    Great question! Info about the all-electric Nissan LEAF's battery can be found here: http://www.nissanusa.com/leaf-electric-car/index.j... - there's an informative video and you can ask Nissan's experts a question right from the site.

    The LEAF is also currently touring the country with Nissan's team of experts who would be happy to answer your questions about the car, the battery, and zero emission driving in general. Enter your zip code and check out when the LEAF is coming to your town here: http://www.nissanusa.com/leaf/events

  • 1 decade ago

    Does it really matter. In reality they use pulse width modulated DC. Which has the characteristics of AC in many cases. Its far more complex that merely AC or DC.

  • 1 decade ago

    depends what kind of motor. However I recon AC

  • Anonymous
    1 decade ago

    dpens on the motor i use motor oil but ur choice and no copying!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!11

    Source(s): idk wikipedia whats ur source u *888
Still have questions? Get your answers by asking now.