Beep and Tunes Generated by Motor?

[Yeek]

Hi ya'll,

I am quite surprised when I tested the HobbyWing ESC today with the programming card. When I selected the numerous power-up tunes, I realized the sound is coming from the motor and not the esc.

Is this the norm for all escs? Never noticed that before. How on earth does the motor make music when there is no speaker diaphragm or membrane?

The hobbywing esc also gets quite hot when I played around with the tune selection. Normal?

Cheers!

Yeek

[Artyspec]

Nearly all ESCs have a tune which they make the motor play. So it is perfectly normal. No idea how they do it!

p.s. Outrunners seem to be louder and small inrunners seem to be softer!

[shmuckerz]

yea i found it kinda weird that the sound was comming out of the motor...
i guess the ESC gets hot because settings are being changed, which must use alot of power?
(dono if im right)

cheers
shmuckerz

[P4cm4n2000]

hi Yeek...i think the tune comes from the wires...ultrasonic vibration......if you bring them near your ear immediately after powering on..you can hear it wisptering...."Go fly now!"..... (make sure you don't mount the prop yet when doing this action...else you can challenge Arthur with your ear instead of nose" keke...

say...did your esc comes with Lambada tune?

[lu wei yao]

HEy guys.
Its perfectly normal for all ESCs.
The sound does come from the motor and not the ESC itself.

It's something about the ESC sending out signals to the motor.

Thanx!

[Yeek]

COol!

Wow this is cool! How on earth did they "vibrate" the motor to a tune? Reminds me of the "Beyond 2000" handphone implantation design that vibrates your tooth for listening to incoming calls.....man......RC designs pretty cutting edge man!

Yeek

[Yeek]

Music Box

Hahaha! No lambada man, but got Oh Susanna, jingle bells, Auld Lang Syne and many more! Will disable the music immediately man, too shy to operate a karaoke in the field!

Yeek

hi Yeek...i think the tune comes from the wires...ultrasonic vibration......if you bring them near your ear immediately after powering on..you can hear it wisptering...."Go fly now!"..... (make sure you don't mount the prop yet when doing this action...else you can challenge Arthur with your ear instead of nose" keke...

say...did your esc comes with Lambada tune?

[Artyspec]

so we still dunnoe how the sound is created. But i think the CastleCreations melody is one of the best!

[temannis]

How a speaker would work. Electrical +/-ve pulses send to the coil of the speaker, causing the coil to vibrate in/out, producing sound wave. For the motor, same thing applies, the electrical pulses was send to the motor, causing it to rotate rapidly cw/ccw in very small increment, thus behaving like a speaker. If u notice, the prop rotate a little side to side when the tune is playing.

[Artyspec]

yea i noe it has something to do with the motor's movement. I have even tried turning the motor manually by hand when the tune is playing. YES it does affect the tune. But normal speakers use these current to vibrate a cone.(thus moving air) but i got no idea how the motors can move the air.

[temannis]

For inrunner motor, vibration of the motor rotor was transmitted to the motor casing, but majority of the energy will transmit to the gear and ended up to the prop, so in a sense, the prop is the "speaker cone" that amplify the sound wave. Without attaching the inrunner motor to anything, the sound volume should be softer because the vibration is transmitted from the motor case only.

To make different note, the ESC will cos the motor rotor to vibrate in the required frequency.

[Artyspec]

cool. One day they will come up with polyphonic melodies! (dream on... )

[temannis]

To add on.. I noticed the amp draw peak around 6 to 8 amp when the tune was played on my ESC. I am using anolog AMP meter, so the needle jump up and down like those old HIFI set's volume meter. Those people borned around my era will know what i am saying.. haha

[khatiban]

cool. One day they will come up with polyphonic melodies! (dream on... )

i guess ESC manufacturers won't be interested in polyphonic melodies... but i really hope that future ESCs might come up with custom mp3 ringtones like those in mobile phones

[khatiban]

To add on.. I noticed the amp draw peak around 6 to 8 amp when the tune was played on my ESC. I am using anolog AMP meter, so the needle jump up and down like those old HIFI set's volume meter. Those people borned around my era will know what i am saying.. haha

based on my experience with electric motors and analog multimeters. these are the possibilities i could think of

• the ESC generates high frequency electric pulses to the motor in order to create the sound in your motor. The electric current changes so quickly that the needle on your ammeter simply bounce back and forth.
• electric motors draw a lot of current when stationary(not spinning)...therefore
• 6-8amps peak might be possible but do take note that the needle tends to overshoot and indicate a higher value when there is a sudden change in current through the ammeter. so the ammeter might not be as accurate when measuring pulsing signals