Model Boat Mayhem - Forum

Technical, Techniques, Hints, and Tips => BRUSHLESS Motors and Speed Controllers => Topic started by: john54 on March 11, 2009, 02:46:09 PM

Title: Very Quiet E.S.C
Post by: john54 on March 11, 2009, 02:46:09 PM
Hi All
I have a mystery 60amp e.s c ,2700k.v outrunner on lipo3s (30c) now the e.s.c arm & programming tones have become VERY quiet  {:-{
She still runs very well but this is a tad worrying as i dont know why!
Any ideas?
Cheers John
Title: Re: Very Quiet E.S.C
Post by: stallspeed on March 11, 2009, 04:12:56 PM
The piezo diaphragm speaker,without the plastic enclosure does not resonate as well if the crystal cracks or the edges are not pinched as before.Thermal deformation is likely but it will not affect the function of the esc and can be easily replaced.

or remounted and heatshrink replaced.
Title: Re: Very Quiet E.S.C
Post by: john54 on March 11, 2009, 05:08:16 PM
It did get very warm once due to over proping & more volts  :D
Now watercooled (useing alloy tank) they are cheap (ish) 22. Worked out its about 12hr old anyway so time for a new one :-)) not worth trying to repair it.
Title: Re: Very Quiet E.S.C
Post by: stallspeed on March 11, 2009, 05:59:00 PM
John,you need ten bob worth of heatshrink,a hairdryer and probably no solder.

Title: Re: Very Quiet E.S.C
Post by: john54 on March 11, 2009, 06:04:28 PM
Worth a try then :-))
Title: Re: Very Quiet E.S.C
Post by: Martin [Admin] on March 11, 2009, 06:36:45 PM
I thought most Brushless ESC's used the motor as the speaker....  {:-{
Title: Re: Very Quiet E.S.C
Post by: stallspeed on March 11, 2009, 07:07:03 PM
I thought most Brushless ESC's used the motor as the speaker....  {:-{
If it is one of the cheap ones that is probably correct.
In which case a 64 ohm speaker or earpiece hooked up to the outputs should liven things up.
Having not tried that before,I would use a series resistor(volume control) just in case.
Title: Re: Very Quiet E.S.C
Post by: john54 on March 12, 2009, 09:52:24 AM
Dead right Martin :-))  Tryed slightly turning the motor (1 pole) when arming loud , quiet , quiet , loud ect. Allen bolt faceing up LOUD every time ! Spooky. 
Title: Re: Very Quiet E.S.C
Post by: andrewh on March 12, 2009, 01:20:37 PM
John,

As you have discovered the loudness depends on the type and acoustic properties of the motor - specifically the rotor of an outrunner .

Dunno if your high KV motor is an outrunner, but if it is it must be 22 or 28mm diameter and about 10mm long so the rotor is pretty bell-shaped.

The ESC should be ok, however abused (it should protect itself thermally), but if the motor arming tune has changed it may be that the motor magnets have got a little overheated and distressed/weakened - have you another motor you can plug in and try?

There is a post on the causes and shape of Brushless failures in Brushless basics in case it helps eliminate some worries :} 

andrew
Title: Re: Very Quiet E.S.C
Post by: john54 on March 12, 2009, 01:57:17 PM
Hi Its an outrunner make & model unknown 2700kv arm dia 28mm length 21mm I wish i knew more specs :((
Title: Re: Very Quiet E.S.C
Post by: john54 on March 12, 2009, 02:05:10 PM
pic
Title: Re: Very Quiet E.S.C
Post by: john54 on March 12, 2009, 02:25:29 PM
Sorry about the big picture C*CK UP 1st file to big 2nd wrong pic 3rd c*ap phonecam x2 >:-o >:-o