Noisy mid drive Tong Sheng

[Alex76]

I bought a s/h bike with new Tong sheng mid drive 48volt TSDZ2 conversion kit 14 months ago, now has 1300 miles on clock. Over the last week or so the motor has become increasingly noisy.

Any tips, advice as to procedures to try and reduce noise would be most appreciated.
Thanks

 

[Bikes4two]

I know it won't be easy to do, but a video/audio clip of the noise would be useful to see/hear.

Out of the 4 tsdz2 I've fitted, one of them is noticeably noisier by far than the other three and the owner bought a tsdz2 B to replace it. He's given me the old one and despite my best efforts so far, the damn thing is still noisy when the motor cuts in.

I've had it apart numerous times and changed a couple of suspect bearings including the 'blue gear' but haven't resolved the issue yet.

The next step is to remove the blue gear and reassemble the motor and see if on powering up the motor the noise persists.

If it does, then the motor itself is the issue. If no noise, then it's something to do with the alignment/meshing of the blue gear and the helix motor drive shaft.

Anyone else got any suggestions?

 

[Bikes4two]

The next step is to remove the blue gear and reassemble the motor and see if on powering up the motor the noise persists.

If it does, then the motor itself is the issue. If no noise, then it's something to do with the alignment/meshing of the blue gear and the helix motor drive shaft.

Anyone else got any suggestions?

• So today I took out the blue gear and re-assembled the motor and on powering up ........ it was still noisy - so it is the bare motor unit creating the noise then!
• I've currently got the bare motor unit out on the bench and having removed the 6 casing screws I've parted the stator windings from the rotor (aka runner, as in the bit with the magnets attached, leading to the term an 'inrunner' BLDC motor).
• From a pic from else where it seems that the rotor can be detached from the rotor casing, revealing I presume, the Hall Sensors (can anyone confirm this?)
• Before I do that, I'd like to test the Hall Sensors - how do I do this anyone?
• There are 5 small wires on a plug: Red, Black, Yellow, Green, Blue which I'm assuming are the power supply (Red, Black) for the 3 phasing hall sensors?
• Again I'm assuming that if I re-assemble the bare motor unit and connect up the 5-way plug and power up the whole, then by rotating the bare motor shaft I should see the hall effect devices switch the supply voltage through each Hall Sensor in turn.
• On the stator side I'll check continuity between each phase and am wondering whether to do an insulation test betwen the windings and the casing 0 but at what voltage if I do?
• Anyone else with ideas what to look for whilst I've got this noisy beast apart?

The journey continues, but I am getting the feeling that this motor is for some reason, just a noisy one for reasons beyond my Ken!

 

[Nealh]

Some are dead quiet some are noisier , my one is a noisier one but it doesn't bother me.

 

[Bikes4two]

Some are dead quiet some are noisier , my one is a noisier one but it doesn't bother me.

• A poster on ES shares your views and I know from the 4 motors I've fitted to different bikes that this is the case.
• My own motor is whisper quiet - on a par with or better than the likes of Yamaha, Bosch et al.
• However, this particular motor is noisier by some considerable order at a 'stand out from the crowd' level and beyond something I can tolerate.
• I'm also wondering if the controller might be a contributing factor? I'm stretching the bounds of my knowledge here but I've gleaned from many postings where the controller waveform is talked about, e,g, square wave being noiser than sine wave and many mentions of how OSF results in a quieter motor than the OEM firmware.
• Once I've done some cold checks on the bare motor, I think the only thing to do is to swap it with my whisper quiet bare motor and see what happens.
• Ultimately new bare motors come in around £100 depending on place of purchase (and annoyingly PSWPower don't seem to want to sell this unit to the UK) and if I have to bite that particular bullet, so be it!
• Anyone got a redundent 36v TSDZ2 knocking around their bike shed?

 

[saneagle]

The hall sensors are always in the stator.

 

[Bikes4two]

Once I've done some cold checks on the bare motor, I think the only thing to do is to swap it with my whisper quiet bare motor and see what happens.

• I did not check out the Hall Sensors but rather just swapped the bare motor from the 'noisy' TSDZ2 over to the 'whisper quite' build and it is the bare motor unit that is noisy, definetly!
• In the follow few pics which I include for others who may find themselves stripping a bare motor unit down, I got as far as separating the rotor and stator and removing the Hall Sensor unit (all one piece and part of the connecting plate for that stator windings, so no chance of changing individual Hall Sensors I'd have thought).
• With the rotor separated out from the stator, the rotor appeared to rotate smoothly. I would have liked to have separated the three bearings and rotor from the motor casing head, but I'm not sure how this is done.
• Anyway, there were no signs of motor overheating or any surfaces rubbing against each other, so for the moment I'm scratching my head as to why this particular bare motor unit is much noisier than the other unit - any suggestions folks?
• Maybe one of the rotor bearings is noisy under load? Can Hall Sensors partially fail as in they don't give a clean switch (similar to the 'switch bounce' of a mechanical switch)?

 

[Bikes4two]

Since my last post I've been tinkering and am currently awaiting a new set of bearings for the rotor spindle to see (hopefully) if the motor runs quiet.

Rather than duplicate my efforts, I've posted further information on the Endless Sphere fourm, so for those who might have an interest, the ES link is HERE.

For the curious, here's a diagram of the rotor and it's constituent parts.


Any feedback/suggestions are most welsome.

 

[Bikes4two]

New bearings fitted, bare motor re-assembled and placed in main body and ........ this motor is now as quiet as the other motor that I have.

Of the 4 original bearings, one of the 61800 RS wasn't quite as smooth as the others and maybe under high RPM/load was responsible for the noise, but at a cost of under £15, I just changed them all.

 

[guerney]

Wow, you did it! Must feel satisfying, solving that noisy puzzle. I was half expecting some sort of active noise cancellation mod.

 

[Nealh]

Well done Alan and thanks for posting , quite happy with my unit at the mo but have earmarked the bearings needed should I decide to fiddle with motor. My philosophy now that it is fitted is if works leave it unless it gets really bad.

The bearing being 2rs type one asumes as they have double seals.
Any particular brand or manufacture country ?
I have ear marked some Swiss made bearings.

 

[Bikes4two]

Hi Neal (@Nealh ),
I didn't do much research at all about replacement bearings other than a brief query about the type of bearing seals and for reasons that I can't recall, I chose bearings with code ZZ.

In the absence of any particular knowledge I went for bearings branded as 'Dunlop' which on receipt the packet said Made in China - huh! The ebay seller is called 'nationalbearings'.

For future refernce, I'd be interested in a link to those Swiss bearings please - just in case, lol!

I met a friend of mine today and I mentioned the noise/bearings etc and the one bearing that didn't feel quite as smooth as the others and he said that the mearest imperfection in a high RPM motor would likely be noisy and he's an engineer of some considerable experience.

 

[Nealh]

My TSDZ is a power/controller noise, as when I cycle with no power it is quiet.
A noisy bearing would show up whether powered or not , I would have thought.

I saw the Dunlop one and thought great then saw region of manufacture, but that doesn't always mean poor quality.
China have come on in leaps and bounds in some areas and their astro glass/eye pieces are a match now to the best US & Japan made lenses.

61800 2rs - 61810 2rs SEALED HIGH PERFORMANCE CYCLE E BIKE CARTRIDGE BEARINGS UK | eBay

 

[Bikes4two]

My TSDZ is a power/controller noise, as when I cycle with no power it is quiet.
A noisy bearing would show up whether powered or not , I would have thought.

Thanks for the link Neil.

Have a look at YT for 'TSDZ2 Motion study final' by Guy Dal (link) to see that when cycling with no power the Blue Gear* isolates the bare motor drive shaft from pedalling action, ie the bare motor isn't rotating with power off (or zero assist selected on display).

Your symptoms are exactly the same as mine were.

*(also a sprang clutch but not termed that way so as not to become confused with the large sprag clutch in the main gear wheel)

 

[Bikes4two]

• So I went out for a longer test ride this morning (40+ miles, 50% quiet lanes so good for 'motor listening') and although this repaired bare motor is considerably quieter than before the change of bearings (pedestrians were literally turning their heads as I approached), it is still not as quiet as my first unit.
• Given what I said about pedalling with no motor power/zero assist and bare motor drive spindle being idle at this point, I switched off assist and everything got quieter! (see note below).
• Damn, and I've changed at the bare motor bearings, so what could it be?
• And then of course I realised that there is another bearing that rotates with the drive spindle which I hadn't changed, and it is the 696-2RS bearing that is pressed into the main unit body case and supports the drive spindle as per the pic below.
• For the hell of it I shall order one of those and wait for a rainy day to swap it out.
• As an example for those who've not stripped their TSDZ2 down (yet?), once I've got all the necessary tools to hand (see pic below) it is 15mins or less to get the crank and unit cover off and the bare motor out (and then you can service the blue gear if needed)
• It would take maybe another 10 - 15 minutes to break down the bare motor unit and old bearings off.
• Obviousy I've now had some considerable practice, but I'm a bit ham fisted at times so I'd feel confident that for the first timer and someone familiar with tools, they could do the above in around double the times I've given.

Note: For those with a noisy motor, pedalling and switching motor assist on and off whilst listening to see what happens to the noise, will help to pinpoint which part of the overall unit might be the cause, i.e. the blue gear, main gear and supporting bearings, vs the bare motor bearings and the drive spindle 696 2RS support bearing.

•