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Hard usage & reliability

Discussion in 'Technical' started by Brent, Sep 7, 2007.

  1. Brent

    Brent Member

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    Reading about last month's White Zombie vs. Mazda drag race, I noticed that the Zombie edged out the Mazda by a small margin, although the Mazda blew some sort of engine component at the end. This failure evidently happened after the finish line, and so didn't mean that the Mazda would have otherwise won.

    The race brings up a question that has gnawed at me for some time, however. Just what sort of driving will cause an electric car to fail? I realize that the fewer moving parts should make for less maintenance, but there must be a failure point. Does hard driving increase the chance of such a failure? Could I expect the Roadster's motor to last ten or twenty years if I floored it every time, from every stop?

    I read something about AC Propulsion having motors going on several hundred thousand miles. I'm not sure, however, how they were driven.

    Perhaps these questions will only be answered by time and experience.
     
  2. donauker

    donauker Member

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    A properly designed AC motor that has protection against over temperature operation will not really be affected by hard use. I would say the primary failure point would be any transmission/transaxle unit.
     
  3. TEG

    TEG TMC Moderator

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    The electric motor in your washing machine or dryer is not so dissimilar.
    They can last a lifetime.

    I would say that the biggest enemy is heat. Hopefully the control electronics will protect the eMotor, but I would say the worst case situation would be something like you tried to use the roadster to push a heavy vehicle up a hill.

    Or you floored the accelerator pedal and held down the brake pedal at the same time. If the motor controller is trying to make the motor spin, but some huge force is preventing it from spinning then I think the motor makes heat instead of motion which can melt the insulation on the windings causing motor failure.

    I think it would be possible for Tesla to design in safeguards that ignore your request for more power when the controller knows it is going to damage the motor.

    Driving 130mph up hill (say highway 5 "grapevine") in 115 degree weather would probably be unfriendly to that air cooled motor... (The highway patrol wouldn't approve either!)
     
  4. TEG

    TEG TMC Moderator

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    Oh, I see Don had a similar response as I was composing mine. I am glad we are thinking along the same lines!
     
  5. Brent

    Brent Member

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    So the motor itself is unlikely to fail.

    I guess the spindle could snap under stress, but it's probably designed with some excess force tolerance.

    My Mercedes' motor mounts seem to go bad every couple of years. An electric motor doesn't vibrate like an engine, but there must be a stress point where it's attached to the car.

    These concerns aside, I'm really hoping for a car that operates with the reliability of a refrigerator, with only the obvious wear points like tires and brakes to manage.
     
  6. TEG

    TEG TMC Moderator

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    Theoretically they should be able to make everything very durable but it is known that the batteries wear out eventually.

    Along with the batteries, the tires will wear out (as they do on all cars) and perhaps fairly quickly given the performance characteristics of the roadster.

    I worry about the durability of the body. Carbon fiber is a bit of a new / not-totally proven technology here.

    There are also a lot of CPUs and control system that need to be durable. Small components like capacitors and fans can go bad due to temperature, humidity, dust and such.

    Some people shy away from a 1st year model even from a big car company that has a proven track record. This is Tesla's first model as their first effort. And they are a small company with very limited experience in this industry. They are making a valiant effort, but they have to figure out how to do a lot of things right to produce a product with "industry standard" durability, fit-and-finish and such.
     

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