Electric motor whine when stopping

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by joules, Sep 13, 2018.

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  1. joules

    joules Junior Member

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    Over the past few months I've noticed that sometimes when coming to a full stop I hear the whine of an electric motor. It happens just before coming to a full-stop, so at speeds less than 10mph.

    I'm guessing its related to the regenerative braking and its effect on the electric motor.

    The Prius has 230,000 miles so I'm not entirely surprised.

    But ... I'm interested in experiences and thoughts from other owners. Should I be looking at some particular repair or expect a major failure soon?
     
    #1 joules, Sep 13, 2018
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  2. bisco

    bisco cookie crumbler

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    i have heard that on many hybrids since new. it is inverter whine, no worries.
     
    #2 bisco, Sep 13, 2018
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  3. KK6PD

    KK6PD _ . _ . / _ _ . _

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    It's when you stop hearing it you should start to worry.....
     
    #3 KK6PD, Sep 13, 2018
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  4. jerrymildred

    jerrymildred Senior Member

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    It's the sound of regenerative braking, which is done in loose terms by an electric motor running backwards. It sounds about the same when you accelerate by electric only. It's making the same sound at higher speeds, but is masked by louder noises.
     
    #4 jerrymildred, Sep 14, 2018
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  5. joules

    joules Junior Member

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    Thanks for the thoughts. They're about in-line with what I've been expecting.

    I've put 200k on the car and this noise is something new over the past few months. I expect its part of normal wear and tear. Thankfully there are no other catastrophic sounds coming from the car.
     
    #5 joules, Sep 14, 2018
  6. edthefox5

    edthefox5 Senior Member

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    No a mechanical whine is not normal.

    Have you ever replaced the trans fluid? Have you ever replaced the water pump belt?
     
    #6 edthefox5, Sep 15, 2018
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