PWM Frequency and compatibility of ESC's

Hi all,

I'm using a Turnigy Trust 55A ESC (well, trying to use) ESC.

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=12190

Using my O-Scope, I can see the PWM output of the APM2, and it's 490 hertz or so, but the pulse widths are the same as the receiver output which is 49 hertz or so.

The difference is the frequency, the pulse widths are nearly the same throughout the range.

My problem is that if I connect the ESC directly to the receiver, it works fine.  But connected to the APM2, the ESC's just play this one repeating musical note at about 10 hertz.  A very annoying musical composition to say the least, plus it doesn't work!

I can see the output of the APM2, other than the frequency, it's the same as the output of the receiver.

So it looks to me like the APM2 isn't compatible with the Turnigy Trust ESC's. 

Is there a solution to this problem?

Thanks,
Dan Gray

P.S.  this will be my 3rd set of ESC's for this machine.....

Here's my history of ESC's.  First I purchased 50 amp RedBricks from hobby king.  I tested one alone, and was able to get 2.5 LBS of thrust from one motor.  

The moment I connected the 4 ESC's PWM wires together on the APM2, Not a peep came from these RedBrick ESC's, they all completely stopped responding in all respects.  They are DEAD, no beeps, nothing.  I went on the HobbyKing Website, and looked at the reviews, and almost everyone had problems with them.

I was in a hurry, I purchased from a local hobby shop, some 35A Swift SkyRC ESC's, and installed those.  These worked, but they have an AutoZero "feature" that makes them Beep Slowly ALL THE TIME, unless you're actually spinning the motors!  

My solution was to change the firmware 2.7.3 to put out a slightly higher PWM when APM2 wasn't enabled.  This made the beeps only happen when the APM2 was enabled.  This allowed me to use the swift ESC's.  But they only provided 1.7 LBS of thrust, so I wanted to change them.  Also, two of them failed during configuration!  Had to make another trip and buy more from the hobby shop.

So, now there's THREE ESC's that I simply DO NOT LIKE!

Ok, I looked at the Turnigy's, and checked the reviews, they seemed fine.  But now I have this third problem as described above, and I'm really frustrated.  I want to fly my new machine!

Any help would be appreciated.

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Replies

  • Are you plugging the ESC's into the APM or into a Power Distribution Board?

    The reason I ask is I have this problem with some OS ESC's in that they will just sit there if I use the PDB but will operate if I them directly into the APM.

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