1LikesBrushless motor only runs when the rod is turned by hand
12-24-2018, 07:55 PM
#1
Brushless motor only runs when the rod is turned by hand
I have a used Reedy Sonic M3 17.5T motor. It worked fine yesterday and early today. For some reason now, it won't run when I press down on the throttle. It only emits a high pitched noise. I tried resetting and recalibrating the ESC, but the motor still doesn't work properly. I only have one sensor wire, and all the shops are closed. I also tried reversing the sensor wire, and still nothing. The motor just emits a high pitched noise. I'm trying not to free run the motor too much as I don't want to break anything else. I'm trying to get my buggy to work before I head off for winter vacation.
Is there anything else I can do? I'm charging my LiPO battery right now to see if it'll do anything.
Any help is greatly appreciated!
Is there anything else I can do? I'm charging my LiPO battery right now to see if it'll do anything.
Any help is greatly appreciated!
12-24-2018, 10:31 PM
#2
Have you checked if the motor spins without the pinion gear connected?
If the motor spins but the car isn't moving, it is likely that your differential is too loose. These do loosen as the car wears in and require adjustment.
If the motor spins but the car isn't moving, it is likely that your differential is too loose. These do loosen as the car wears in and require adjustment.
12-25-2018, 07:35 AM
#3
Yes, I tried without the pinion gear. The motor still won’t work properly. It only spins if you turn the rod. Is this a motor problem or an ESC problem?
If I took apart the motor and did something (I don’t know what), could that possibly make it work right?
My servo works, the ESC fan spins. It’s an XR10 Justock.
If I took apart the motor and did something (I don’t know what), could that possibly make it work right?
My servo works, the ESC fan spins. It’s an XR10 Justock.
12-25-2018, 08:05 AM
#4
Tech Prophet
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Sounds like bad sensor wire. My Reedy in my F1 would make that sound. There probably and spot the sensor wire that’s damaged. Or could be just wire. I’ve had to replace mine twice in 2 years.
12-25-2018, 12:08 PM
#5
It is also possible that one of your three main leads has a bad solder joint and has become disconnected.
12-25-2018, 05:36 PM
#7
I also noticed that my motor only runs if I hand crank the rod. I know I said that before, but it lasts for a bit. The motor won't start back up if I leave it in neutral for more than a second. Less than a second, it'll keep going.
12-25-2018, 05:50 PM
#8
Tech Prophet
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The sensor wire, as in the one that connects the ESC to the motor? My motor is good though, right? And I don't think it could be an ESC problem, as my servo works.
I also noticed that my motor only runs if I hand crank the rod. I know I said that before, but it lasts for a bit. The motor won't start back up if I leave it in neutral for more than a second. Less than a second, it'll keep going.
I also noticed that my motor only runs if I hand crank the rod. I know I said that before, but it lasts for a bit. The motor won't start back up if I leave it in neutral for more than a second. Less than a second, it'll keep going.
Second time the wire just seem to just go bad. Never found a visible break, but was using a longer then needed wire, and had folded it up and ziptied it.
Since the first time I’ve always kept a spare sensor wire( or cable as it also called). It’s a cheap part to keep as spare.
12-25-2018, 09:56 PM
#9
Tech Master
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Like Billy said above, most likely a sensor cable. This also happens if the sensor cable is not fully plugged into the esc - I had a HobbyWing esc that had a problem with the cable slipping out on my off road car if it wasn't mounted securely.
#2 reason could be a bad sensor board followed by a bad esc. Also, the servo working is not necessarily an indicator that the esc is good - the servo is running off the BEC built into the ESC.
And finally, the "rod" you are spinning is called a rotor - the magnets inside the motor are attached to the shaft you are spinning.
Hopefully you have a local hobby shop that can help you out. It would be great if you can find someone with a motor analyser to pin point the fault.
#2 reason could be a bad sensor board followed by a bad esc. Also, the servo working is not necessarily an indicator that the esc is good - the servo is running off the BEC built into the ESC.
And finally, the "rod" you are spinning is called a rotor - the magnets inside the motor are attached to the shaft you are spinning.
Hopefully you have a local hobby shop that can help you out. It would be great if you can find someone with a motor analyser to pin point the fault.
12-27-2018, 07:25 AM
#10
Tech Regular
I had this issue when one of the widnings in the motor detached from the front 'bridging' tabs. This was a Tekin motor that had over temperature use. By measuring with the multimeter one of the phases was open (mesured with motor detached from esc). I resoldered it as it's still working fine.
12-27-2018, 08:34 AM
#11
Tech Master
Lets assume there are 3 electromagnets in a brushless motor. They are oriented in a way that if any 2 are on you get the rated torque of the motor and it does what its supposed to do. If only 1 is on it has half the rated power. You need 2 of them to be on to accelerate the motor from 0 but 1 on will keep the motor rotating if its already at some speed.
a bad motor, wiring, sensor, esc are all possible culprits. when this comes up I try to work in this order:
1-remove load from the motor (what happened)
2-check all of my wiring with a multimeter
3-take a b or c off one at a time and when it does the same thing you dont like that is the phase with the problem.
4-quick winding check-disconnect from esc and short all 3 phases of the motor to the case (paper clip or something). Rotate the motor. In between the bumps in the rotation you will feel a fluid resistance in the form of rotational drag and it increases the faster you go. Make sure its symmetrical between each one of the bumps.
a bad motor, wiring, sensor, esc are all possible culprits. when this comes up I try to work in this order:
1-remove load from the motor (what happened)
2-check all of my wiring with a multimeter
3-take a b or c off one at a time and when it does the same thing you dont like that is the phase with the problem.
4-quick winding check-disconnect from esc and short all 3 phases of the motor to the case (paper clip or something). Rotate the motor. In between the bumps in the rotation you will feel a fluid resistance in the form of rotational drag and it increases the faster you go. Make sure its symmetrical between each one of the bumps.
12-28-2018, 01:52 PM
#12
Unplug your sensor wire and see if does the same thing or not. Most sensored esc's can run sensorless.
12-28-2018, 02:36 PM
#13
Sorry for the late reply.
I went to a RC shop in Dayton about two days ago, and I got a Reedy sensor wire (6 pin) to replace my old one, along with a rather large 48P 29T pinion gear.
The motor does run without the sensor wire, but it's slow. With the new sensor wire, the motor runs. The motor (pinion gear) with the spur gear makes a grinding noise at very low throttle, but after throttling up a bit, it runs fast I guess. No more grinding noise except for a brief second when going from a stand-still to takeoff.
Is 20 mph too slow for a 17.5T 2WD buggy (1/10 scale)? I ran on carpet (with carpet tires of course) at my hotel.
I went to a RC shop in Dayton about two days ago, and I got a Reedy sensor wire (6 pin) to replace my old one, along with a rather large 48P 29T pinion gear.
The motor does run without the sensor wire, but it's slow. With the new sensor wire, the motor runs. The motor (pinion gear) with the spur gear makes a grinding noise at very low throttle, but after throttling up a bit, it runs fast I guess. No more grinding noise except for a brief second when going from a stand-still to takeoff.
Is 20 mph too slow for a 17.5T 2WD buggy (1/10 scale)? I ran on carpet (with carpet tires of course) at my hotel.
12-28-2018, 02:49 PM
#14
Tech Prophet
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Yes. 20mph sounds slow. Could be a gearing issue. The other noise, just guessing could be either in the diff or bad gear mesh. But that just guessing.
12-28-2018, 03:02 PM
#15
You should never hear a grinding noise, even at slow speeds. Check to see if the spur and pinion are in good shape and set them so there is just a little backlash (you can rock one gear back and forth a tiny amount with the other gear held stationary).
Good luck.
Good luck.
