Discussions

Occasional motor 'clicking' - is this normal? (already changed motor bullets)

Posted by Paul Feely on January 16, 2011 at 4:37am

I think I know the answer to this but I'd appreciate a second opinion before stripping down...

 

Fah Pah ArduCopter kit, ready for first flight, everything working well except occasional 'clicks' from motor(s), can't tie it down to one motor in particular.

 

I've changed out the bullets on the motor side and are nice and tight now (they were all loose), wiggling wires doesn't seem to have any effect...I didn't change the connectors on the ESC side.

 

I've attached a mp3 of the clicking, if someone can listen and tell me if it's normal or not that would be a help.

 

If not normal I'll replace the connectors on the ESC side and get the the Power Distribution board out and have a look at the Deans etc - anything else that I should look at?

 

Many thanks, Paul

quad motor click.mp3

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Replies

  • Mauro Rodriguez January 24, 2011 at 6:03pm
    All my motors do that sound!! so for me is very normal!! lol lol :):):):)
  • Paul Feely January 24, 2011 at 1:58pm

    Thanks for all the feedback on the clicking.....

    Consensus seems to be it is ESC and ok (although change out bullets if Fah Pah motors).

    Took Quad out for first flight at weekend....fantastic, clicks and all !!

    Usually my first flights are over fairly quickly and are followed by lots of super glue, scrapping bits off the deck and an early bath. Expected same with quad but no problems at all this weekend.

    I've only ever flown fixed wing before and was blown away with how stable the quad was....GPS hold was excellent, much better than I thought it could be (returning to hold point under own steam great), can't wait for waypoints and a bit more autonomy....many thanks to all the contributors. 

    Was a very foggy day so no video/pictures of flight, couple of indoor pics below, not much to see standard kit.

    Now looking into navigation strips lights (can be a bit dull in Scotland), weather proofing (it's wet in Scotland) and a camera mount (to take nice pics of a dull, wet Scotland;)

    Thanks again Paul

    3692157970?profile=original 

    3692157868?profile=original

  • Ground Loop January 19, 2011 at 10:55pm

    I'm hearing the same.

     

    I don't know if it doesn't happen in hover, or if it's just drowned out by the other noise.  It's most noticeable in the "armed" and idling state.  It doesn't seem to impact the flight at all.  The pace is pretty constant.. and the volume of each 'tick' is about the same.  I figured the ESC was just burping now and then.  I haven't seen it 'kick' in hover or flight, so I have to think it's a low-RPM problem?

     

    This is totally different than the horrible bullet connectors, which burnt up a motor early on.  Desolder all the motor/ESC bullets, and solder the wires together.  Those motor bullet connectors are garbage, and the ESC ones might not be soldered on very well.

  • Troublemaker January 19, 2011 at 10:24pm

        I would think that if you could place either the main battery leads or one of the motor phases on an oscilliscope you could see if the voltage is spiking.  A large voltage spike generated could possible cause a spark/crackle but it would have to be in the order of several thousand volts genrated to break down or jump across insulation/gaps. I have never had that sort of clicking before ever from single esc's running in aircraft and I have had around 30-40 different ESC's and motor combos. 

        I know that some ESC's allow you to change the switching frequency and the timing, that may help.  Also could it possibly be related to some sort of periodic cycle lining up (due to the software loop restarting/resetting? and/or multiple ESC format?) and causing one phase to misfire?  If a phase fires out of order a large voltage could be induced or a strong magnetic field could be produced at the wrong time which could be in oppostion to the other magnetic fields, my guess that would try to load/lock the rotor and could make a sound.  If you short out a petrol generator for example, the magnetic field locks the rotor so strongly the motor will stop, and large truck mounted genrators can rip free of mounts and destroy themselves!

        If you dont have an oscilliscope to look for spikes, what about possibly some sort of strobe you could adjust to see the motor standing still then possibly jumping out of sync after a click?  That would at least tell you if it was physically happening to the rotor, or else just an electrical sound.

        With changes in loading, I have had magnets clip the rotor, and that is actually quite common, as the magnets are often laid up in epoxy fairly roughly in some constructions.  The idea is also to place the rotor as closely to the stator as possible to reduce magnetic flux losses through the air gap, so they are pretty tight tolerances!  You will be able to tell if that was the case by pressing out the shaft and inspecting the stator for scuff marks. 

      Also could it be the prop adapter nut/plastic slipping?  Unlikely I know.

      Good luck I am very interested to know what the answer will be!

  • Overwatch January 19, 2011 at 11:28am
    I found an ESC (TGY Plush 25A) that does it too. Standard PWM, no mods. Feels like the ESC fails to sense the position of the rotor and issues a bad switching command, wrong sets of coils get triggered and this results in a sharp and short braking effect on the rotor, which we hear as a click. It seems that it doesn't happen at higher RPMs though, only when idling. When I get over the neutral lift threshold there are no more clicks that I could feel or hear.
  • Developer
    Jani Hirvinen January 19, 2011 at 5:04am

    This type of click sound is rather normal. Different ESC's clicks with different pace. It is due fast update rates to ESC. Many of ESC's have 150Hz filter running and it seems that sometimes when filter kicks in this click sound is formed. 

     

    Many AeroQuad, ArduCopter etc users have similar clicking sound and it never created any problems. Converting ESC to I2C or uploading FastPWM software on those sometimes removes this click sound due available opensource softwares does not use any filtering and like said, this seems to remove click sounds.

     

    My test quads have always been having this same sound, freq just changes a bit depending on what flight software I use. Still using my original ESC's on all quads and never had any problems with them. During my hundreds flight hours I've only broke 1 single motor and that was due really violent crash.

     

    (Who says to land upside down with full throttle, 3mm motor shaft cut broken from middle. Just changed motor Bell, rest of the motor is still in active use :) )

     

    I try to hook up signal and 3-phase lines on a logic analyser on somepoint to see what happens during click pulses. If someone happens to have analyser close by. Just go and look it too...

  • Choppy January 19, 2011 at 2:24am
    Just check one esc and motor WITH prop with the receiver. Let it get to some load/ temp. This is how I found almost all of my "loading" failures. I fried a motor recently when I tried to upload with the motors connected so bought a new one. Forgot to resolder the bullets on the new one and 4 mins into the flight, cork screwed it into the ground at a great rate of knots. I'm a idiot.....
  • Franck January 19, 2011 at 1:42am

    Hi!

    I'm building my new Arducopter and I have the same issue on my motors. I have to test which Esc is responsible.

    Regards

    Touchthebitum

  • John D. January 18, 2011 at 7:56pm

    Hey, I just got my quad in the air a few days ago and I am getting that same "click" sound. It is a bit unnerving. When building the quad I soldered the ESC to motor bullets solid but after a flip today I found a cold solder joint on one of the motor side bullet to wire (possibly caused by me when I soldered the whole thing solid). My quad is tested and "usually" flies well so I'm just going to remove the bullets completely. One less thing to worry about, until I have to take it apart again. LOL! The ESC power wires are also soldered directly to the Power Distribution board.

    -John

  • DougB January 18, 2011 at 6:23pm
    At least on my Quad I know that the connections are not the problem, I've replace all the connectors with Castle Creations connectors and tested them.
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