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MG2 replaced, polarity reversed???

Discussion in 'Generation 1 Prius Discussion' started by Kevin Ward, Sep 8, 2017.

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  1. Kevin Ward

    Kevin Ward New Member

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    My Son recently replaced the MG2 stator in his 02 Prius, with a brand new one. Now the car tries to go forward in reverse, and attempts to move in reverse when placed in drive. We have been through every scenario to determine where the polarity could be incorrect. The only thing I can think of is that the stator itself was reversed at the factory. Anyone have other ideas, before we tear it back down? This is a weird one.
     
    #1 Kevin Ward, Sep 8, 2017
  2. ChapmanF

    ChapmanF Senior Member

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    I can think of two things that would do that. The obvious one would be interchange of any two of the three stator leads (a three-phase motor reverses any time you swap two of three leads). But probably you have checked that.

    The other would be disturbance of the motor resolver during the replacement effort. The resolver is the thing on the inside of the motor end plate that has some electromagnetic coils and a small rotor, and it reports the rotational position of MG2 back to the HV ECU in high precision (1/4096 of a revolution, IIRC). That is the information the HV ECU uses to time the current waveforms it sends to the stator to spin the rotor in one direction or the other. It's important not to disturb the resolver during the work; I don't think Toyota ever published a recalibration procedure for if it gets out of adjustment.

    -Chap
     
    #2 ChapmanF, Sep 8, 2017
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  3. Kevin Ward

    Kevin Ward New Member

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    I talked to my son, and he did in fact loosen the bolts on the resolver. So we will be calibrating. I'll post the results and findings when we get him back on road. Thank you so much, for sharing your knowledge.
     
    #3 Kevin Ward, Sep 9, 2017
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  4. T3chtonic

    T3chtonic New Member

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    UPDATE*
    The new motor has an issue with it.
    We put a salvage MG2 in and the runs great now. ROCKAUTO.COM (whom we bought the motor from) won't accept returns after 30 days, luckily there is a lifetime warranty from Dorman.
     
    #4 T3chtonic, Feb 27, 2018
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