Erfolg Posted April 2, 2015 Share Posted April 2, 2015 I have built a model which has two motors. Each motor has an identical ESC The motors are controlled via one channel The control wires are connected into a "Y" connector, into this single channel. I had an issue where when closing the throttle, I would get erratic stopping of the motors. I decided this is primarily due to one ESC. I then ordered a replacement. The replacement has arrived and has replaced one of the ESC along with the "Y" lead. I reset the motor throttle range. I now have the issue consigned to the one ESC that has been replaced. Has any one experienced a similar problem. What was the problem and then the solution? Quote Link to comment Share on other sites More sharing options...
Toni Reynaud Posted April 2, 2015 Share Posted April 2, 2015 I don't know if this would have any bearing on the matter, but when using two ESC's, if you are using the BEC embedded in the ESCs to power the Rx, it is generally recommended to remove the red lead from one of the ESCs to prevent the BEC outputs "fighting" with each other or to prevent damage to one of them. If you have both ESC red leads connected, then as the power taken from the ESC to power the motor drops, this might have an effect on the BEC circuitry and and this in turn might cause the behaviour you describe. Just a thought. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted April 2, 2015 Share Posted April 2, 2015 If the BECs are switch mode type then it is important to disconnect one red wire but if there are linear BECs it makes no difference. My own test would be to shut the throttle and then disconnect the signal wire on the ESC that has stopped. If the other motor still continues to run then clearly its ESC has not actually 'learned' the throttle range. If removing the signal wire on the other ESC causes the running motor to stop then there must be some sort of interference going on between them. I have several twins (and one 4) that run quite happily on Y leads from the throttle channel (and all the red leads are connected too!). Quote Link to comment Share on other sites More sharing options...
Erfolg Posted April 2, 2015 Author Share Posted April 2, 2015 The Rx is driven via a UBEC. The output from from the two ESCs is fed into a "Y lead, which is connected to a very short EXT. lead, which has the red lead disconnected. As you will have seen my Delta ( a twin) runs happilly. Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted April 2, 2015 Share Posted April 2, 2015 Does each ESC work OK if plugged directly into the Receiver, if that's the case it maybe because you are asking them to share the "position" signal and it's not strong enough for those particular ESCs Quote Link to comment Share on other sites More sharing options...
Erfolg Posted April 2, 2015 Author Share Posted April 2, 2015 Frank Both work fine by themselves. I will double check tomorrow, as this check was done 3 or more weeks back. What is the position signal and is there a solution, perhaps a separate channel for each ESC? Quote Link to comment Share on other sites More sharing options...
PatMc Posted April 2, 2015 Share Posted April 2, 2015 If I understand it correctly both BECs, although not being used, still have all 3 wires connected to each other. It might be possible that this is causing some false signal to be generated between the two ESCs. You could try disconnecting the red wires from each ESC. If that doesn't solve the problem try calibrating the ESCs again individualy. When re-calibrating make sure the throttle trim is set to centre or high then if there's still a problem set the trim to low for normal operation. Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted April 2, 2015 Share Posted April 2, 2015 Posted by Erfolg on 02/04/2015 17:11:15: Frank Both work fine by themselves. I will double check tomorrow, as this check was done 3 or more weeks back. What is the position signal and is there a solution, perhaps a separate channel for each ESC? The ESC or servo gets it's position from the Rx via a pulse sent down the signal wire, the length of this pulse will determine the position, while the signal is essentially a voltage pulse this still has to flow through the ESCs control circuit (current) if the Rx can't deliver the small current required by both ESCs the signal voltage will collapse and the ESCs won't see a clean signal. This is more common now with 2.4 receivers where the signal processing and signal pulse work at a low voltage (not to be confused with the power to the servos which will be whatever the BEC or Rx battery gives). Separate channels would eliminate the problem, or a different receiver might also be able to drive 2 ESCs simultaneously, or different ESCs might not demand as much current in the control circuitry. Quote Link to comment Share on other sites More sharing options...
Toni Reynaud Posted April 3, 2015 Share Posted April 3, 2015 +1 for trying this "You could try disconnecting the red wires from each ESC." They could still be interfering with each othe through the Y lead. Not all linear voltage regulator chips have reverse voltaqge protection - ie, one slightly higher output can feed back into the other. Quote Link to comment Share on other sites More sharing options...
Sam Wragg Posted April 3, 2015 Share Posted April 3, 2015 Remove the Positive wire off one of speed controllers where it plugs into the Y lead.This will disable the Bec of the esc which is causing the problem. Sam Edited By Sam Wragg on 03/04/2015 08:16:31 Edited By Sam Wragg on 03/04/2015 08:18:35 Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted April 3, 2015 Share Posted April 3, 2015 Yes it might be that Carl. Driving the second esc via a spare channel may prove the best option ( mixed obviously as a slave to throttle master ) This will allow tweaking of epa etc on each speedo seperately Quote Link to comment Share on other sites More sharing options...
Attilio Rausse Posted April 3, 2015 Share Posted April 3, 2015 power the receiver from a battery and leave the bec outputs disconnected for testing purposes. Quote Link to comment Share on other sites More sharing options...
Erfolg Posted April 3, 2015 Author Share Posted April 3, 2015 I will take the time to read the replies properly. It does seem that I need to write down a structured approach, which hopefully identifies what the issue is. I know that primarily I want a solution, i also would like to understand the cause. Not least, as it could help me avoid a similar issue. Thanks for your suggestions and interest. Carl Quote Link to comment Share on other sites More sharing options...
Erfolg Posted April 6, 2015 Author Share Posted April 6, 2015 Oh dear. I have now found that there is a problem on the one side. With a new ESC on the faulty side the problem is still there. That is after taking out the "Y" lead and running the motor direct, with a short extension lead to isolate the red +ve lead. I have tried reprogramming the ESC to ensure that the throttle range is correct. That has no effect. I am wondering can this have anything to do with the motor. For some reason the ESC can be heard via the motor noise to reset itself after closing the throttle. Although the motor does not shut down immediately after shutting the throttle, continuing to run for a few seconds, if the throttle is opened after shutting down and the motor stopped, opening the throttle, nothing happens, then the motor often resets (the esc noise) then it restarts. Using new escs, it seems it can only be the motor, in some way, could this be so? Quote Link to comment Share on other sites More sharing options...
Barryorbik Posted April 6, 2015 Share Posted April 6, 2015 We had a similar problem with an esc on a helicopter recently and it turned out to be poorly soldered connections on the motor connectors, one of which was only being held in place by the heatshrink sleeving. Seemed that once the motor had pulsed a few times then started rotating it ran up OK but closing the throttle frequently caused the motor to fail to spool up again and caused the esc to re- arm. Barry Quote Link to comment Share on other sites More sharing options...
Dave Hopkin Posted April 6, 2015 Share Posted April 6, 2015 I have had a couple of mtors with bullets attached in China that were problematic both turned out to be dry joints on the motor bullets as fitted in China - worth checking out Erf Quote Link to comment Share on other sites More sharing options...
Erfolg Posted April 6, 2015 Author Share Posted April 6, 2015 Dave If it is a bullet problem, then the problem would be me Barry I do take some reassurance from yourself and I think Dave, that the problem is motor related. I have a new motor on order. When i do replace it I will carefully examine the old motor, although The problem may not be really that easy to find. Quote Link to comment Share on other sites More sharing options...
Keith Simmons Posted April 8, 2015 Share Posted April 8, 2015 Hi Carl, I doubt you could find what's wrong with the old motor as you say they work independently, I suspect you have tried swapping the motors over & do you then have the same problem on the original side or on the other side? I am keen to know what your findings are that caused the glitch. You can then use the old motor for your next project 😃 Keith Quote Link to comment Share on other sites More sharing options...
Erfolg Posted April 8, 2015 Author Share Posted April 8, 2015 Just the one motor is effected using the same ESC and cables via the same channel. Quote Link to comment Share on other sites More sharing options...
Sam Wragg Posted April 8, 2015 Share Posted April 8, 2015 Do you use 1 pack to drive both motors / Esc. If so; could it be back emf affecting the other Esc? Have you tried using two indipendant packs? good luck Sam Quote Link to comment Share on other sites More sharing options...
Dave Bran Posted April 8, 2015 Share Posted April 8, 2015 Posted by Erfolg on 06/04/2015 15:21:30: For some reason the ESC can be heard via the motor noise to reset itself after closing the throttle. Although the motor does not shut down immediately after shutting the throttle, continuing to run for a few seconds, if the throttle is opened after shutting down and the motor stopped, opening the throttle, nothing happens, then the motor often resets (the esc noise) then it restarts. That sounds like the ESC is in soft start or is actually one specific for heli use Quote Link to comment Share on other sites More sharing options...
Erfolg Posted April 9, 2015 Author Share Posted April 9, 2015 Dave The ESC used is identical on both sides, plus the new one is identical, it is just the one motor that is the issue, so it appears. The two motors run from the the same Lipo via a UBEC. Quote Link to comment Share on other sites More sharing options...
Phil Green Posted April 9, 2015 Share Posted April 9, 2015 How about trying a Y lead on each throttle channel with a spare servo paralleled to each esc, then you can see what signal the ESCs are getting from the rx - maybe the ESC is only doing as its told to do by the rx Quote Link to comment Share on other sites More sharing options...
Erfolg Posted April 9, 2015 Author Share Posted April 9, 2015 Phil I have tried to run the motor as a single unit. That is direct into the Rx, via the an Esc, using a extension lead with the red +ve lead isolated.. The issue persists, irrespective of which ESC is used. Yet running the other motor, in a similar manner that motor runs as is usual. It is this aspect which suggests to me that the issue is the motor, not "Y" leads, Escs. If the new motor confirms this conjecture, I will then examine the motor more closely, with a view to establish what the problem is. Quote Link to comment Share on other sites More sharing options...
Phil Green Posted April 9, 2015 Share Posted April 9, 2015 Sorry I didnt explain very well, the purpose of the Y lead is to see (via a spare servo) exactly what signal the ESC is seeing. It could be that the ESC is only obeying rogue signals from the rx, which you would see on the servo. If the servo sits still whilst the ESC is going crazy then at least you know its not that. There is nothing to a brushless motor really, I can only think of badly soldered bullets... Cheers Phil Edited By Phil Green on 09/04/2015 16:18:43 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.