Noises a brushless motor might make
04-04-2007, 10:51 PM
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Noises a brushless motor might make
I have an Electristar RTF plane. It came with a mystery brushless motor which someone in the electristar thread identifed as a Rimfire. The ESC was a SS45D. Well I let the smoke and fire out of the ESC because it got a little wet the other day (don't ask.) So now I've replaced it with a Castle Creations Phoenix 80 (spare amperage for a larger plane in the future)
Now, everytime I start the motor by advancing the throttle the motor makes a very loud sort of high pitched tone as the prop is started which then goes away immediately after rotation has been established. Otherwise it seems to run the same as with the old ESC. I measured the amps coming from the battery and got 30 amps whereas before I was pulling only 28. (x2 7 cell NIMH 3000mah 20c).
I also programmed the ESC for the lowest timing advance and this changed the amperage draw back to 28. I turned off the soft start function and also the brake function. I left the switching rate at default 13 khz. The old ESC had a switching rate of 8.5 khz I believe. Could it be the difference in switching rate that is causing the odd startup noise?
Does anybody else's brushless motor make any kind of wierd noises when starting from a standstill.
Now, everytime I start the motor by advancing the throttle the motor makes a very loud sort of high pitched tone as the prop is started which then goes away immediately after rotation has been established. Otherwise it seems to run the same as with the old ESC. I measured the amps coming from the battery and got 30 amps whereas before I was pulling only 28. (x2 7 cell NIMH 3000mah 20c).
I also programmed the ESC for the lowest timing advance and this changed the amperage draw back to 28. I turned off the soft start function and also the brake function. I left the switching rate at default 13 khz. The old ESC had a switching rate of 8.5 khz I believe. Could it be the difference in switching rate that is causing the odd startup noise?
Does anybody else's brushless motor make any kind of wierd noises when starting from a standstill.
04-05-2007, 06:52 AM
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RE: Noises a brushless motor might make
My small rimfire makes a high pitch squeal when I first fire it up as well... I just ignore it and keep flying as, according to my watt meter, everything is otherwise just fine with it
04-08-2007, 08:43 AM
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RE: Noises a brushless motor might make
The squeal you hear is generated by the CC speed control but comes from the motor. Quirky, but harmless. In my case only the 80 amp CC does it.
07-09-2007, 01:45 PM
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RE: Noises a brushless motor might make
Yep. me too. I have a Torque motor with a Phoenix 45 that squeels at spin up then goes away once the rpm passes about 1000.
07-09-2007, 09:12 PM
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RE: Noises a brushless motor might make
Well, the Phoenix 80 I have driving the rimfire motor on the electristar still makes that squeal on startup. I've been flying it with no problems. For my new plane/project I have a Phoenix 110HV and an Axi 5345/14 combo. This does not make any squeal on startup. The motor just simply starts without any fuss.
07-10-2007, 12:23 AM
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RE: Noises a brushless motor might make
Often the PWM-frequncy is heard when the motors run. Often it is 8kHz, but might be higher, like 13kHz. A high frequency sound...
