*resolved* Loud knocking noise coming from Brand New MP - then dies (again)

[Magzy]

I have just assembled my new MP this weekend.

When I put the MP under any slight load, I hear a loud knocking/ticking noise. I'm not saying this is the cause but to give you an idea what it sounds like, it sounds like a cable tie is catching against a set of closely grouped spokes - and only happens when the MP is under load.
I can lie the bike flat and there will be no noise except for a very faint whirr (as I would expect it should operate) but as soon as I put any kind of resistance on the wheel, the noise starts and only stops when there's no resistance.

This is a big issue for me because I specifically bought the MP because I wanted it to be quiet and now I'm very disappointed about this noise.

I've not taken it apart to see if there's anything inside causing the noise because frankly I would not know what I'd be looking for.

Can anyone diagnose this noise and help me fix it?

.Edit to add that the motor has just died;
.Edit to add that the Controller was replaced twice and the motor once - pinging noise is still there but is somewhat fainter. Thanks to gary GM canada for not leaving me out in the cold with this debacle.

[Cornelius]

Have you checked the tension of the spokes? My spokes was slightly on the loose side, and made such noises when under load...

[Magzy]

Hmm, this could make sense, but the noise it too uniform for it to be any couple of spokes.

I checked them and they were really tight right out of the box

Also another reason I doubt that it's the spokes is that If I pedal hard without any throttle applied then I should get the noise right? but I don't get the noise. But as soon as I apply the throttle under load, I get the noise.

its almost like there's a lose wire  sparking on something on the inside of the hub or a lose cable tie that is catching on something. only when there's resistance in the wheel while the throttle is on.

Help!

[Cornelius]

Could it be one mis-aligned hall-sensor?
That would make the controller fire one of the phase pulses slightly out of phase, making a knocking sound...

[Magzy]

Could it be one mis-aligned hall-sensor?
That would make the controller fire one of the phase pulses slightly out of phase, making a knocking sound...

Maybe. how do I check for this?

[Cornelius]

I guess one has to open the motor and visually inspect the positions of the hall sensors... (There are several posts here on how to open the motor.)

But i'm not an expert there; maybe others here can help you, or have better theories?

[Rob9771]

Same thing happened to mine. While sitting on at full weight knocking noises but when standing on just one pedal ( scooting along) quiet.
I think it is spoke related / not great quality wheel building.

[Bikemad]

My guess is that the noise you are experiencing is probably quite normal, as these motors are not silent and can be heard at some distance.
I think the noise is caused by the quick pulses from the coils being transmitted through the stator as they try to pull against the magnetic force of the strong permanent magnets. Because the Magic Pie has a large diameter hub, the stays (the 8 thick spokes shown below) at the centre of the stator are long enough to flex slightly with each magnetic pulse, causing a regular series of audible "pinging" noises.

The more powerful the magnetic forces, the louder the noise will be, therefore the noise will be relative to the load on the motor.
I also think the stator noise is being amplified by the hub side covers, which can ring like a bell when removed.

But that's just my theory.

Alan
 

[Magzy]

It can be heard 100m away and is quite loud.

To put this into perspective for you, I saw another MP user drive up the hill outside work a month ago, I was just 5m away from him and his motor didn't make the same knocking noise that mine has it was smooth with a faint whirr.

mine sounds like it was built by the clampets http://en.wikipedia.org/wiki/The_Clampets

Now, I've just discovered that my motor doesn't work at all and the wheel has locked up - even with no batter connected to it.,

This is going from bad to worse.

 

[GM Brazil]

I'll bet in ball bearings again

No load = silent (can only hear the engine itself)
With load = extra noise

[Magzy]

I'll bet in ball bearings again

No load = silent (can only hear the engine itself)
With load = extra noise

This is exactly how it behaves.

so bearings?

how can I check the bearings.

and how can I get the motor to work again? its just died - i.e. no power to the wheel [I have a ping pumping out 53v at 30 AH max]

[Cornelius]

Oh, could it be a loose coil that moved into the rotor when energized? (and now has been worn out and made open circuit?)

I think you now have no way out of opening your motor to find out; either to check for hall sensors, bearings or loose coils... (or even a wire...)

[GM Canada]

Hello Gary

Please ask your customer to check the bearing.He should disconnect his motor.
How to know the bearing ok,or not?
One finger holds inside ring of bearing,use other finger to turn the outside of bearing.If it can run for a long time,it's okay.
 
Best Regards
Tom

I asked Tom about it and this was his reply. I have never had a motor apart but maybe someone here can tell us if its an easy thing to check. I don't quite understand what Tom means in testing the bearings, does it have to come apart to test?

Gary

[Magzy]

Hello Gary

Please ask your customer to check the bearing.He should disconnect his motor.
How to know the bearing ok,or not?
One finger holds inside ring of bearing,use other finger to turn the outside of bearing.If it can run for a long time,it's okay.
 
Best Regards
Tom

I asked Tom about it and this was his reply. I have never had a motor apart but maybe someone here can tell us if its an easy thing to check. I don't quite understand what Tom means in testing the bearings, does it have to come apart to test?

Gary

Gary,

A pic of Tom doing what he says will indicate if the housing needs to be taken off or the spindle disassembled and this will dictate if the task is beyond my capabilities or not - or if I have the time and the inclination to correct mistakes made by the manufacturer.

To add insult to injury, the motor has now stopped responding to any input and the wheel has ground to a halt like it's being held in place by the magnets in the wheel - even with the battery disconnected. The horn or any of the controller reset options are not working either.

What do I do with this thing now?

[GM Canada]

Sounds like a mess to me. Ill contact you in private email and we will get this taken care of.

Gary