Thread: SBEC Noise??
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Old 07-08-2014, 05:01 AM   #2
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Originally Posted by Flysfloats View Post
I have a problem that exceeds my level of experience so I am hoping for some help. Last year I installed a NTM 42-58 500kv motor and Turnigy Thrust 70A SBEC speed controller in my newly completed Sig 4 Star model.

On my maiden flight I had a transmitter(of course!) issue and the flight was about 30 feet with a dinged wing tip and broken motor mount. Recently I completed my repairs and took the plane to the field for maiden flight II. A very nice and smooth flight with no issues UNTIL I was on final and then landing. I, and several others, heard a noise coming from the plane. After clearing the runway I checked the plane out for something loose or ? I then did a static run up and as I got near full power a loud "ratcheting" noise came from the plane.

At home I installed a brand new identical motor and tried again but without a prop. The shaft barely turned over and a noise came from the SBEC!!! Any idea what could be causing this? Both the SBEC and original motor only had a 5 second flight last year and a 5 minute flight this year since new. With a similar noise coming from another new motor and me being able to actually pin point the source of the noise, this should be easier to solve.

Additionally, can I try reprogramming the SBEC? Do you use the Programming Cards that can be bought with BECs? I have a hard time listening to the chimes/tones that come from the BEC and making heads or tails of them.

Thanks in advance for your help. FF
Are you certain the noise came from the SBEC? FYI, the SBEC is a Switching type Battery Elimination Circuit that generally operate at 50 or 100 Kilohertz, far above normal hearing range. These SBEC's provide the five volts DC to operate the receiver and servos. Even if that SBEC went nuts, I don't think you'd be able to hear it. And, if it did, it might fry your receiver and servos.

IMHO, that noise more likely originated from the ESC (Electronic Speed Control) that directly drives the motor. The ESC drives the motor, and the noise you hear would be from the motor itself. In fact, my feeble memory recalls that someone in wattflyer found a bad solder joint on one of the three motor wires inside the shrink wrap of the speed control itself. Resoldering fixed it.

Many other people in Wattflyer have indicated that this sort of thing often is caused by poor or intermittent connections between the three wires between the ESC and motor.

Double check them, and make certain they are solid connections. If they are, the next item would be to swap out the ESC, if possible.

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