Author Topic: DC MOTOR NOISES (Thrustmaster T500RS sim racing steering wheel)  (Read 3422 times)

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Offline perkabrod

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Re: DC MOTOR NOISES (Thrustmaster T500RS sim racing steering wheel)
« Reply #25 on: January 17, 2018, 06:46:28 pm »
Okay. Obviously I don't have enough arms to pull out a proper oscilloscope test, so bare in mind that this link is captured with the ground probe floating. The red + probe is connected to + terminal on DC motor.
https://youtu.be/gVAbqVpBr9I


There's continuity (or 4-5 ohms) between dc motor + and - terminals (measured while the PCB is connected)

Here's a photo taken on the scope while having both probes hooked up, ground on motor housing and red probe on + terminal on motor.


When measuring with the multimeter I got -12 VDC at the motor housing, with the - terminal on motor as reference. I also measured the heat shield on power transistor closest to the large capacitor (on a pcb located near the left padle shifter, this gave me 12 VDC but I cannot remember if it was + or -. The other power transistor heat shield measured 0 V, still the same reference (DC motor - terminal).

I did try a few different capacitors (0,1 - 1 uF) in parallel with motor but no difference what so ever in noise.

Duty cycle 50% = motor standing still
=> I don't get it... I thought the duty cycle should be 0% when no movement, and then 0-100% (0 to +24 V square wave with duty cycle aka PWM) to move one direction, let's say clockwise CW, and 0-100% duty cycle negative (0 to -24 V PWM) to move CCW.

Replying to myself: Locked Anti-Phase PWM control
In locked anti-phase PWM control, the amount the voltage signal “swings” from a positive voltage to a negative voltage is used to control the motor.  In this case, forward and reverse motion depend on the duty cycle of positive voltage versus negative voltage, with the 50% duty-cycle equaling a stationary motor.  For example, if the voltage across the motor is positive for longer than it is negative, the motor will move forwards.  The same is true for the opposite: if the voltage is negative for longer than it is positive, the motor will move backwards.  Therefore, if the positive duty cycle is higher than 50%, the motor will move forwards; if it is lower than 50%, the motor will move backwards.

source:https://www.google.se/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0ahUKEwiB5_7a59_YAhXTbZoKHTkYCcUQFgg2MAE&url=https%3A%2F%2Fwww.systemseng.cornell.edu%2Fse%2Fintel%2Fteam%2Fupload%2FMotor-Controller-Guide.docx&usg=AOvVaw33H71VprwAx6MwX1PdmByg
« Last Edit: January 17, 2018, 08:22:46 pm by perkabrod »
 

Offline Armadillo

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Re: DC MOTOR NOISES (Thrustmaster T500RS sim racing steering wheel)
« Reply #26 on: January 18, 2018, 04:12:27 am »
I can tell you the motor sounded angrily powerful when its turning.   ;D
Sure don't look or sound like a commutator problem to me.
I noticed only when the pinion slowly rotate and you placed the microphone so close that I can hear the rubbing click click click sound.
When it stood still I cannot hear it, example there is no chattering.
If you powered it on and at 50% pwm, pinion not moving and it chatters, then its commutator chattering otherwise IMHO, sounded like loaded motor bearings.

The scope signal looks healthy as far as I can visibly see.
The 50% PWM at full peak voltages, I think is for a purpose to hold/grip the steering wheel in place. Otherwise it's a waste of energy for non gamer like me.

Hey, considering the loudness of the drive vs the clicks [10,000 : 1], I say it's a "acceptable".  ;D

Edit: The NETT average voltage during holding should be "ZERO", it would be this remnant voltage that could cause the unnecessary chattering and commutator wearing. For normal turns, the optical feedback signal will make sure the PWM turns the motor.
So Check that the Positive voltage and the Negative Voltage excursion/drive are equal resulting in 50% Nett Zero current and voltage.


« Last Edit: January 18, 2018, 04:44:09 am by Armadillo »
 

Offline perkabrod

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Re: DC MOTOR NOISES (Thrustmaster T500RS sim racing steering wheel)
« Reply #27 on: January 18, 2018, 05:09:53 am »
Yes, this is no toy :D It's powerful enough to make you slip on the steering wheel while playing. Yes, no noise when in a "idle position", noise is only heard when you rotate the wheel just a fraction of a degree. The annoying thing though is that when playing, that noise will be heard 90% of the time because of the delicate movement while in a long corner for example.

Maybe the pcb on the motor terminals is for the noise reduction. Hard to see but I see a few tiny ceramic disk capacitors. I also figured that the gooped looking cap is probably a temp sensor, it is strapped on to the motor housing with cable ties.

Maybe have to live with the noise :) Tomorrow the angled screwdriver will be delivered, if I'm in the mood I might carry on and remove motor and investigate...

I wrote that the cap didn't reduce the noise but I realized I did it wrong, connecting one leg of the cap to motor terminal + and the other leg to motor housing, and the housing is not connected to the negative terminal. So there's some hope still that a cap is faulty, will look at the pcb on the motor terminals, one motor is removed.

Do you know if the dc motor noise reduction document you linked, also work with locked anti-phase motor control, like in this case?
« Last Edit: January 18, 2018, 06:52:14 am by perkabrod »
 

Offline Armadillo

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Re: DC MOTOR NOISES (Thrustmaster T500RS sim racing steering wheel)
« Reply #28 on: January 18, 2018, 09:38:56 am »
Regarding the capacitors, Yes it will work with the anti-phase motor control. To the cap, it's just delta V. The purpose is to reduce the slew rate of the pulse / average the drive. Considering the plus and the minus voltage, the capacitor voltage selection should be 100v or more. 0.1uf type is more to reduce the radio frequency noise. 1uf and up would be more for averaging.

But you should resolve the following which I think is more critical.;


Edit: The NETT average voltage during holding should be "ZERO", it would be this remnant voltage that could cause the unnecessary chattering and commutator wearing. For normal turns, the optical feedback signal will make sure the PWM turns the motor.
So Check that the Positive voltage and the Negative Voltage excursion/drive are equal resulting in 50% Nett Zero current and voltage.

Why the Vmax 18.32v is greater lesser than Vmin -27.71v? The H-Drive merely invert the power so should be same. You should check.
The Vavr is 2.01v, it should be zero during idle.






« Last Edit: January 18, 2018, 03:57:40 pm by Armadillo »
 

Offline perkabrod

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Re: DC MOTOR NOISES (Thrustmaster T500RS sim racing steering wheel)
« Reply #29 on: January 18, 2018, 06:27:58 pm »
...You should check.
The Vavr is 2.01v, it should be zero during idle.

That cheap oscilloscope based the values graphically, I need to zero/tar before measuring in order to get readings I can trust. I measured today with DMM and there's 6 mV between + and - terminal on motor. I also probed the 4 power transistors and couldn't find any noise or weird voltages (measured this with motor case as reference and got reading of 12.12 VDC, 24 VDC etc.)

I also tried a 1 uF between MOTOR terminals but no difference in noise. Right now I'm doing a recalibration of the center point, found a guide on how to do that. http://ts.thrustmaster.com/download/accessories/manuals/t500rs/t500rs_autocalibration_centering_process.pdf

I will make another video then which has some interesting stuff that I didn't think of too much before, but could potentially mean something for any of you with experience ;)
 

Offline Armadillo

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Re: DC MOTOR NOISES (Thrustmaster T500RS sim racing steering wheel)
« Reply #30 on: January 18, 2018, 07:07:58 pm »
That's OK.
Looking forward to your interesting video.  :)
 

Offline perkabrod

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Re: DC MOTOR NOISES (Thrustmaster T500RS sim racing steering wheel)
« Reply #31 on: January 18, 2018, 07:55:07 pm »
https://youtu.be/-4KfLH-VoCI

In games there is no return to centre, because the steering wheel will just follow the input from the car physics, so the electrical noise will be heard when turning both CW and CCW. I re-assembled the base plate so that I could do some sim racing tonight, hope to find an end to this soon, or accept the noise :)
 

Offline perkabrod

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Re: DC MOTOR NOISES (Thrustmaster T500RS sim racing steering wheel)
« Reply #32 on: January 19, 2018, 07:14:01 pm »
Such a lovely screwdriver <3 It arrived today and now the motor is out, will desolder the pcb and test motor with bench supply... Update to follow.



The reason I purchased this screwdriver was because I can come away with not having to disassemble the gear stage with pulleys etc. Lots of screws and potential problems (pulley tensioner etc).
« Last Edit: January 19, 2018, 07:51:06 pm by perkabrod »
 

Offline perkabrod

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Re: DC MOTOR NOISES (Thrustmaster T500RS sim racing steering wheel)
« Reply #33 on: January 19, 2018, 09:35:34 pm »
Motor tests
https://youtu.be/yHzX8w0N_uA

Short video on below 1V showing a little stuttering
https://youtu.be/U5mJKIpSu3s
 

Offline Armadillo

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Re: DC MOTOR NOISES (Thrustmaster T500RS sim racing steering wheel)
« Reply #34 on: January 19, 2018, 09:56:19 pm »
I would say it's bearing noise. I can hear the noise even when the pinion is not loaded.
Change the bearings using proper tools.   ;D
If you can open it up, then you can tell what bearings to buy or you can try check with manufacturer.
I would recommend boca ABEC 7 type bearings.
 

Offline Armadillo

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Re: DC MOTOR NOISES (Thrustmaster T500RS sim racing steering wheel)
« Reply #35 on: January 19, 2018, 10:07:05 pm »
Or consider to change the motor.
Look for 775 type motor but you need to check the mechanics, pinion etc...
DC motor should not cost a hand or a leg.

https://www.ebay.com/itm/1PC-DC-24V-21000RPM-High-Speed-Large-torque-DC-775-Motor-Electric-Power-Tool/331883102354?hash=item4d45c64092:g:Y8gAAOSwJhFZgaKU
 

Offline perkabrod

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Re: DC MOTOR NOISES (Thrustmaster T500RS sim racing steering wheel)
« Reply #36 on: January 19, 2018, 10:52:09 pm »
Or consider to change the motor.
Look for 775 type motor but you need to check the mechanics, pinion etc...
DC motor should not cost a hand or a leg.

https://www.ebay.com/itm/1PC-DC-24V-21000RPM-High-Speed-Large-torque-DC-775-Motor-Electric-Power-Tool/331883102354?hash=item4d45c64092:g:Y8gAAOSwJhFZgaKU

The periodic noise was very easily distinguished irl. I need to reuse the pinion and rear magnet so ig I start removing tjose, I will be able to open the dc motor and look for bearings. If it is not serviceable, at least I know what motor to buy.

Well, the Bühler motor cost a leg or two  :-DD but I have the datasheet, also, in the thread I linked about someone who replaced to more powerful motor, there was a suggestion for a cross reference chinese motor...
 

Offline Ozz

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Re: DC MOTOR NOISES (Thrustmaster T500RS sim racing steering wheel)
« Reply #37 on: November 14, 2018, 04:49:30 pm »
Can I get an update. Im having the exact same sound issue. How did you fixed it? OR did you able to fix it for good :)

Cheers
 


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