Noise from Motor or Transmission.

[Niall B]

Hi all
I have owned a ZS for month now with abot 5000 miles on the clock , of which 500 miles are down to me.
Getting to like the car the more I drive it after tentative start
But there's a noise from the drive train that is niggling me and not sure if it's normal for a electric car.
The noise is most noticeable during town driving and occurre's at the point when you reach your desired speed and then the car go's into momentary free wheel before the motor starts to slow the car down, at that point there's a change in the noise that comes from the Motor/Transmission, it only lasts a second or so but can be made to last longer if the car is in Kirs1 and with a light foot you feather the throttle.
To me it sounds a little mechanical and is certainly a different noise/Pitch to the normal motor whining.
The cars in for its first service next Tuesday and hopefully will get the opportunity to take there demonstrator out to see if I can simulate this noise.
Has anyone else noticed this noise or am I just being paranoid .

 

[Cocijo]

Good idea to try another car when yours goes in. I posted a thread on wiring noise - I’ll dig it out

 

[Cocijo]

Whining- Motor/gearbox noise

Do any of you technical people know exactly what causes the light whining noise (which is normal) on our cars? Is it the electric motor bearings? Is it the transfer gears within the electric drive transmission system? I know that a lot of electric motors these days are near silent.

www.mgevs.com

 

[Lovemyev]

You can hear a slight motor whine on the over run at about 26 - 27 Mph.
You can make the whine come and go by feathering the “Go” pedal.
The Demo car I used was the same.
I think it is a normal condition.
Be interesting to hear what the dealer thinks.

 

[Alan5]

Yes my car is the same , I had a demo ZS EV when my car was in for some work which had 500 miles on it and it also had the same noise as described. My car has now done 10,000 miles and the noise is still the same as when I first noticed it ( not any worse ) . It does sound like it's a noise that other members have noticed and so is normal for the car . I am more inclined to add extra sound proofing at some point although having said that it is a quiet car and you do tend to hear noise's that maybe in an ice car you would not hear or notice . But let us know what the dealer has to say

 

[Mgkev]

To me this sounds normal.

 

[Lovemyev]

Indicative of the model maybe ?.

 

[Mgkev]

All my hybrids made this sound so I wasn’t surprised when I heard this noise in my MG.

 

[Coulomb]

I suspect it might be an inevitable result of using a permanent magnet motor, called cogging torque. Think of the noise that stepping motors make; it's nowhere near as bad but similar.

Some cars, like Teslas, use induction motors, which have no permanent magnets. Such cars would presumably be smoother. But then you have to use some electrical current to magnetise the rotor, leading to higher power consumption at lower speeds. But then permanent motors have to use current to buck the permanent magnet at higher speeds (field weakening), which consumes more power at higher speeds. So it's a compromise.

It's possible that more cars will be forced to use induction or other types of motor without permanent magnets in the future, because of a possible global shortage of noble metals like neodymium that are needed for permanent magnets.