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Planemo

Nasty noise from new MSX 84v

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Guys, just stepped foot on this today in the living room and didnt like this noise at all. It seems very much like the noise is consistent with the magnet spacing in the stator so suggests 'cogging' but my question is, is this normal for the MSX?! Sounds bloody awful, but cant hear it at all once moving (only 25' though across living room). I have confirmed that nothing is touching the tyre.

The wheel doesnt seem to oscillate front to back like the ones @Marty Backe has been describing, but I cant believe this is normal either?

 

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While it is certainly very pronounced in your video, that is indeed the typical "cogging" sound that comes from basically every high-powered wheel in some form or another. Individual wheels have their own "voices", but they all have a bit of a growl to them.

This noise has been spoken about several times on these forums by many different people, but there is one I reference I remember particularly fondly... I don't recall who said it, but the gist of the comment was: "All of the modern high-powered wheels do it, it's just that Gotways tend to be less polite about it."    :roflmao:

Anyway, it's nothing you need to worry about, and like you seem to have noticed already, as soon as you hit about 2-3 miles per hour the sound (and sensation) disappears and the wheel glides as smoothly as if it were on a sheet of glass.

Edited by Arbolest

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I appreciate your comments. Its just so loud that I found it concerning. I am familiar with cogging having experienced it with many brushless R/C motors, ebike motors etc but the only 2 other wheels I have (Z10 and V5) are virtually silent when doing the same test movement. Although I appreciate the Z is a lower wattage motor it isnt that much and I can barely hear it and neither do you actually feel it either (which is very prominent on the MSX). Its alarming to say the least! I have never heard another msx do it either when out and about with other riders.

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This is normal.  Probably not as easy to hear from other MSXs while out riding with environmental noises but I assure you it's not an issue with your wheel.

Edited by MrRobot

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That is completely normal if you are pushing it hard and reversing directions, like idling.

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As everyone has been saying, perfectly normal. That's the sound of raw POWER :D

Enjoy your new beast :cheers:

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Wow I am gobsmacked and shocked but relieved all the same! Really appreciate getting others thoughts, what a forum :)

As I say, you wouldnt have heard anything from the Z so I found it hard to believe that such a stark difference was normal!

We are now properly into winter here now Marty, -1 deg C yesterday so as much as I want to get on this new MSX, I prob wont do much riding for the next 3 months :(

(cue all the hardcore Scandinavian riders!)

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32 minutes ago, Planemo said:

Wow I am gobsmacked and shocked but relieved all the same! Really appreciate getting others thoughts, what a forum :)

As I say, you wouldnt have heard anything from the Z so I found it hard to believe that such a stark difference was normal!

We are now properly into winter here now Marty, -1 deg C yesterday so as much as I want to get on this new MSX, I prob wont do much riding for the next 3 months :(

(cue all the hardcore Scandinavian riders!)

FYI, I've heard my Z10 emit many growling sounds as I've climbed super steep hills. But yeah, otherwise it's a quiet wheel :D

It's only 18-degrees Celsius here today - a bit chilly, but rideable B)

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I wouldn't call it normal. It might be a sign of phase wires having a poor electric contact. Or Hall sensors malfunctioning. I suggest asking this question on Endless Sphere, they know BLDC motors better.

Edited by Aneta

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I get what you're saying re asking elsewhere but I just thought the best info would come from MSX owners themselves who could simply confirm whether mine is wildly different to theirs.

Unless all the other riders have dodgy hall sensor wires as well of course :)

Given that the amount of cogging is highly dependant on firmware and that ebike controllers may be wildly different to EUC's I am not sure that any answers an ebike expert could give would be conclusive.

 

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5 hours ago, Marty Backe said:

It's only 18-degrees Celsius here today - a bit chilly, but rideable B)

Git!

I haven't had any nasty noises from the Z at all but then again I don't really do hills either. That said, the Z has noticeably more whine at speed than my buddies MSX which is silent :wacko:

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2 minutes ago, Planemo said:

ebike controllers may be wildly different to EUC's

They are pretty much the same except the throttle signal comes from gyro/accelerometer sensor (processed by firmware, of course), vs. Hall sensor on handlebar on e-bikes. The basic algorithms of driving a BLDC motor are the same everywhere. Oh, and our controllers don't have an enclosure, for some unfathomable reason (Bluetooth transparency? can have a plastic enclosure, like on RW GT16).

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9 minutes ago, Planemo said:

Unless all the other riders have dodgy hall sensor wires as well of course :)

I'd still open up the controller and motor and check for any loose contacts and loose motor coils.

The very first search result for

https://www.google.com/search?q=endless-sphere.com+cogging+noise

https://endless-sphere.com/forums/viewtopic.php?t=99440
 

"If you have a particularly loud one, its because of the controller, plus one looser wrap on a winding vibrates."

"When you blow a controller shorting the phases, you will recognize full cogging when you see it. Its like heavy brakes are on. If you experience that, its a short on the phases, like a cut wire at the axle, or shorts in the controller."

I've had similar cogging sounds on my e-scooter before motor phase wires failed.

 

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I had that sound before, went away after tightening all the screws holding the pedal hangers to the shell.

When the shell is not securely connected to the pedal hangers it jerks forward just a tiny bit when you accelerate and confuses the sensors which try to self correct in an endless loop leading to the vibration.

Edit: remember it happens to the monster too, when axle shims are loose. Maybe try checking that as all gotways use shims to hold the hangers in.

Edited by Tinkererboi
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1 hour ago, Aneta said:

I wouldn't call it normal. It might be a sign of phase wires having a poor electric contact. Or Hall sensors malfunctioning. I suggest asking this question on Endless Sphere, they know BLDC motors better.

I say it's normal for Gotway. I've owned a few ;)

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25 minutes ago, Tinkererboi said:

I had that sound before, went away after tightening all the screws holding the pedal hangers to the shell.

When the shell is not securely connected to the pedal hangers it jerks forward just a tiny bit when you accelerate and confuses the sensors which try to self correct in an endless loop leading to the vibration.

Edit: remember it happens to the monster too, when axle shims are loose. Maybe try checking that as all gotways use shims to hold the hangers in.

Another possible reason is the axle itself loose in the stator? This also happens sometimes.

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I will check all the plugs everywhere, but everything looked siliconed in when I had both covers off earlier. No sign of movement on the hanger bolts/casing but will check those also along with the axle nuts. It is only happening at low speed though, either when just pulling away or doing quick changes of direction as per the vid. At any other time the wheel is smooth without any issues whatsoever.

Cheers :)

 

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Took this photo earlier, all looks pretty secure and I would have to destroy the silicone thats already present in order to check! Board is coated as well, didnt know GW were doing that.

 

20191205_195220_resized.jpg

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6 minutes ago, Planemo said:

I will check all the plugs everywhere, but everything looked siliconed in when I had both covers off earlier. No sign of movement on the hanger bolts/casing but will check those also along with the axle nuts. It is only happening at low speed though, either when just pulling away or doing quick changes of direction as per the vid. At any other time the wheel is smooth without any issues whatsoever.

Cheers :)

 

Please don't let Aneta convince you to take apart your MSX. Nothing is wrong with it. Save your energies for riding the wheel instead.

If your axle nuts or pedal hangers were loose you would feel strong vibrations/shaking. You are just hearing the low speed grumblings that are more pronounced on Gotway wheels. I have owned and own a lot of Gotway wheels. That's what they do.

Just my opinion.

Edited by Marty Backe

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While my MSX seems much less pronounced than yours

 

it could be that the mic in the video is more sensitive 

 

 

I was taken back initially when I got my MSX

 

all reviews put Gotway at being smooth and quiet, I give it some torque and mine clicks and grinds like this too

 

coming from the INMOTION V10F which is smooth as butter, and super quiet it was a real surprise and I though there was something wrong with it

luckily my ninebot one S2 shudders grinds clicks and pops on hard braking so I’ve been able to get used to it, but it was very off putting at first, didn’t want to hurt my new toy!

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3 hours ago, Aneta said:

I wouldn't call it normal. It might be a sign of phase wires having a poor electric contact. Or Hall sensors malfunctioning. ...

Having owned 3 Gotway wheels now, each with the same behavior as @Planemo's MSX, I would say that it's most likely not caused by any issues with the wiring bundle coming from the motor (phase and hall sensor wires). I personally think it's more related to the firmware implementation that Gotway uses... specifically how abruptly it applies current to the motor as the rotor magnets pass the edges of the stator windings and the sudden changes in torque involved. In my opinion it kind of feels a little bit like a sawtooth wave is being used for control, but that is almost certainly my imagination...

 

1 hour ago, Aneta said:

I'd still open up the controller and motor and check for any loose contacts and loose motor coils.

...

"If you have a particularly loud one, its because of the controller, plus one looser wrap on a winding vibrates."

"When you blow a controller shorting the phases, you will recognize full cogging when you see it. Its like heavy brakes are on. If you experience that, its a short on the phases, like a cut wire at the axle, or shorts in the controller."

I've had similar cogging sounds on my e-scooter before motor phase wires failed.

 

Based on this, I almost feel like what we mean when we say "cogging" isn't quite the same... For reference, I am talking about the phenomenon described at the following link, not something to do with intermittent motor "braking" due to an actual short in one of the wires.

https://www.precisionmicrodrives.com/content/cogging-torque-in-permanent-magnet-motors/

 

Anyway @Planemo, like Marty said:

27 minutes ago, Marty Backe said:

... Nothing is wrong with it. Save your energies for riding the wheel instead.

... You are just hearing the low speed grumblings that are more pronounced on Gotway wheels. ... That's what they do.

 

I know you said that the weather where you are isn't the most conducive to riding right now, but trust me and just bundle up and take it for a spin. Once you're actually moving I think you'll find yourself bonding with your new "beast" rather quickly...  :thumbup:

Edited by Arbolest

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That’s 100% normal on the msx. Mine makes the same noise at low speed. I have over 1000 miles on it now and still makes the same sound. No worries!

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Cheers all. You are right, I should just ride the thing but in this weather I have not much else to do other than look at it during downtime! I think I should take some Man Up pills and get out on it.

So we also have another couple of owners who are saying it's fine. Reassuring :)

I noticed that the board plugs are different to those of others which I have taken screenshots of previously. I only noticed because I have been looking to fit a lift switch. Theres only one unused 2 pin plug so I guess I will try that.

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10 minutes ago, Arbolest said:

I personally think it's more related to the firmware implementation that Gotway uses... specifically how abruptly it applies current to the motor as the rotor magnets pass the edges of the stator windings and the sudden changes in torque involved. In my opinion it kind of feels a little bit like a sawtooth wave is being used for control, but that is almost certainly my imagination...

I think you're absolutely right about this. Most likely, it's sawtooth (maybe not even trapezoid, but triangular approximation of sine wave). In contrast, 16X's remarkably quiet motor is probably due to new controller/firmware combo that produces true sine wave. But coming from e-bike/e-scooter side of PEVs, I've never heard such loud cogging unless it was caused by a malfunction, hence my concerns.

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If this is the case, there must be a reason why GW don't use sine? Ebikes have used it for years, and I presume other EUC manufacturers do as well. Is it harder to implement or something? Or is it just laziness?!

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