Model Boat Mayhem
Technical, Techniques, Hints, and Tips => DC Motors (Brushed) and Speed Controllers => Topic started by: Vanguard on April 17, 2020, 02:33:31 pm
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Hi guys, I've just fitted two mtronik Viper Marine 25's into my Graupner HMS Hood, set them up and tested them, all works fine but I get a noise from the motors a constant beep from just off neutral to quarter then it stops. Is this normal is there anyway to stop it ? 😊 Steve.
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Yes - change the speed controllers for low-frequency ones or fit brushless motors. The noise is coming from the motors' commutators and it's a consequence of the high frequency at which the ESCs pulse the voltage. Low-frequency ESCs just create a low growling noise, which you can tell yourself is the sound of a marine diesel!
Dave M
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It's perfectly normal for vipers. The noise is inaudible when the models are sailing in the 3 I've used.
Chas
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All ESCs work by switching on and off rapidly. Older ones do it 50 times per second, and give DaveM's low growl. More modern ones run at a higher frequency, and cause most motors, beacuse they have most of the components that loudspeakers have, to act as loudspeakers and make a sound at that frequency. Vipers, and many others, are bang in the middle of the human hearing frequencu range, so we hear a whistle. Some ESCs work on yet higherfrequencies. Humans don't hear them, but they might attract the attention of dogs being walked in the park.
Personally, I don't mind the whistle, it lets me know that stuff is working.
Brushed ESCs generally work on one set frequency, and to make the motor go faster, make the pulses longer, offering more power.
Brushless ones need to work at a changing frequency to pulse the motor coils at the right speed. They probably produce plenty of sound, but with everything else going on as speed builds, nobody notices.
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Thanks guy's, as always you know the answers to everything, right off to tinker with her more 😉 regards, Steve.