Juddering Diff or Motor

[draperst]

Hello

Bought a used SSGT with a used Trackstar motor, any ideas what this juddering could be? http://youtu.be/QFWMdOqwr9M

I rebuilt the diff, running a 32T pinion and 70T Spur, all is nice an smooth once up to speed.

I have the trigger on the throttle low then progressively increase the speed.

Thanks
Stuart

[iank55]

First thing to check would be the sensor lead.

[draperst]

Just switched leads, same juddering. I have tried it under load (no weight on the rear vs on the ground) just the same. could it me the motor? The ESC is brand new.

[luniemiester]

Did you recalibrate the radio end points to the speed controller and try increasing your throttle dead band to the next level

[luniemiester]

Also have you wired the A B C wires to the correct terminals as I've seen that before where the sensor board is looking to fire the A phase but it is actually on the B phase etc

[draperst]

Originally Posted by luniemiester

Did you recalibrate the radio end points to the speed controller and try increasing your throttle dead band to the next level

that fixed it (recalibration), thanks.

[shinytopman]

Drape rat
Whenever you change receiver, esc, handset its normally best to recalibrate even if all seems to be fine.
It might look fine but if your not making full throttle it will hurt, especially down the straight.

[draperst]

correction, problem seems to be back, juddering again after recalibration. another strange problem. The motor seems to "stall" any ideas welcome! thanks!

Stuart

[mark christopher]

get a sensor checker such as the core widget, or try another motor and sensor lead, making sure there pushed in make sure the esc is in sensored mode, if another motor and sensor lead make no difference then its the speedo, the radio will not cause your issue

[shinytopman]

Originally Posted by shinytopman

Drape rat
Whenever you change receiver, esc, handset its normally best to recalibrate even if all seems to be fine.
It might look fine but if your not making full throttle it will hurt, especially down the straight.

I must apologise Draperst it seems my wife's iPad auto corrected for me late last night when I was typing (bleeding Apple!)
Next time I'll read before hitting post.

[draperst]

Originally Posted by shinytopman

I must apologise Draperst it seems my wife's iPad auto corrected for me late last night when I was typing (bleeding Apple!)
Next time I'll read before hitting post.

Ha! Not a problem, didn't notice.

[shinytopman]

Anyway hows the issue with the motor/sensor?

I must say it does look like a sensor problem to me from the vid you posted.

When you get a sensor problem the esc cant work out the position of the rotor in relation to the sensors so it has to try and work out which channel to put power down to turn the motor forward, if that makes sence.
Hence the reason for it moving back and forth before it works it out and wants to go.

Try in the following order (of cheapness ). Sensor lead (make sure it is pushed into the sockets properly), Motor, then the only other thing it can be is esc.

[draperst]

Originally Posted by shinytopman

Anyway hows the issue with the motor/sensor?

I must say it does look like a sensor problem to me from the vid you posted.

When you get a sensor problem the esc cant work out the position of the rotor in relation to the sensors so it has to try and work out which channel to put power down to turn the motor forward, if that makes sence.
Hence the reason for it moving back and forth before it works it out and wants to go.

Try in the following order (of cheapness ). Sensor lead (make sure it is pushed into the sockets properly), Motor, then the only other thing it can be is esc.

Hello, its calmed down a bit. I noticed the timing mark was off the scale (its a used motor) rather than being in the marked range, it was over the other side. I think that might have been the problem, not sure as brushless and timing is very new to me. Its still very slightly stuttery but nothing like before. A different sensor lead did not seem to make a difference. I'll wait and get a new motor at some point and go from there. I'm might try it out on a track for the first time on Friday and see how it goes.

On another note, I purchased the capacitors as recommend by Mark, and this seems to have solved the stuttery servo issue on both cars.

I also changed the servo exit position, and managed to pull out the white wire from the board but managed to solder it back, hopefully it won't shake loose.

I have found that I am spending a considerable amount of time on the cars, and really enjoying it. It's a classic hobby whereby you experience a bit of pain now and then, but the learning experience is great!

I might pop down to Maritime tomorrow, and see what it's like.


Cheers and thank you for the continued advice!