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Old Sep 09, 2012, 03:50 AM
Registered User
Joined Sep 2012
7 Posts
Help!
Strange sounds from brushless motor

Hi All

I just bought a Dynam 1200mm Spitfire. It came with preinstalled motor and ESC. Look and hear this video:
Motor i stykker? (0 min 16 sec)

I go to about 25% throttle, then down to 10% and stay there for a bit and finally cut off the throttle. The motor sounds strange and at 10% it sounds like it changes rpm up and down all the time.
Does anyone know if I got a damaged motor or something needs to be adjusted on the equiptment/electronics?

Best regards
Hans Milling...
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Old Sep 09, 2012, 05:31 AM
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United States, FL, Pompano Beach
Joined Oct 2011
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Dose the motor operate properly at other settings? Is the ESC or motor getting hot? I have put together few motor ESC combos that don't have very good running characteristic at the first notch or two on the throttle. In my observation higher cost ESC's tend to have less of these low speed aberrations. From what I have read here on RCG the ESC is working harder at low RPM than at WOT. So there maybe nothing wrong, that's just the characteristics of that ESC and motor.
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Old Sep 09, 2012, 08:00 AM
Jack
USA, ME, Ellsworth
Joined May 2008
16,806 Posts
That prop is not a role model for perfect balance and blade tracking but that is not the issue.

If you tie the plane down and get it running at it's slowest steady RPM you can wiggle each of the ESC to motor connectors and see if one of them has a poor or intermittent connection. Also move the wires where they enter the motor a little too and see if there may be a bad connection inside the motor.

If you can monitor the input voltage from the battery with a meter and see voltage flucuations it may be a bad connector on the battery side of the ESC.

Worst case it might be worth the trouble to resolder all of the connectors. When I do that I take them apart, knock off all of the solder that will come off, then use flux on to re-tin the leads and sockets and also use flux on both as I resolder them. Oatey's No. 5 soldering paste from Home Depot is my choice for flux.

Jack
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Old Sep 09, 2012, 11:10 AM
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Joined Sep 2012
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None of the components get hot. For the assembly and to set all servos to neutral I used an old 1300mAh battery from my old plane. Swapping to a 2200mAh battery and setting the maximum throttle in the esc (Set the remote to full throttle and connect the battery to the plane, then set it to neutral) helped a bit. I just tried to take it to full speed and it seems to run well even though it is a bit noisy. Perhaps I am just used to the little motor from my old plane. You can see the full throttle test at the end of this video:
Short video of my new Dynam 1200mm Spitfire (1 min 20 sec)


Quote:
Originally Posted by zeroback View Post
Dose the motor operate properly at other settings? Is the ESC or motor getting hot? I have put together few motor ESC combos that don't have very good running characteristic at the first notch or two on the throttle. In my observation higher cost ESC's tend to have less of these low speed aberrations. From what I have read here on RCG the ESC is working harder at low RPM than at WOT. So there maybe nothing wrong, that's just the characteristics of that ESC and motor.
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Old Sep 09, 2012, 11:16 AM
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Hi Jack. I will try to monitor the volts and amps and see if anything seems to have a bad connection or if one of the magnets is not working. Thanks for your reply. I'll post my findings later.
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Old Sep 22, 2012, 05:28 AM
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Joined Dec 2011
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Can you feel any rubbing, rotating the motor ? If not, it sounds like a faulty winding on the motor, that would make it run that erratic...

// Per.
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Old Sep 24, 2012, 07:50 PM
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Pleasant Valley Modelport
Joined Sep 2006
8,540 Posts
Check the solder connections on the motor leads, and all the rest of the connections from motor to esc. Maybe one or two strands of wire from the motor did not get stripped well. I recently had a problem with that, it would not start or run well.
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