Electric Stunt > Gettin all AMP'ed up!

Talon 35 will not govern over 10K RPM - Any suggestions?

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Teodorico Terry:
Hello,

I am using a Talon 35 on a small model running in governor mode with the throttle signal generated by a Brodak timer.  The throttle pot on the timer is set to max power which I understand as being a full throttle signal.

The set-up:

  1000KV motor (SunnySky X2820)
  4S battery
  10x5 prop

I am hoping to get about 10200 K RMP but for some reason the ESC will top out at 10000 RPM.  I ran a simple test with the ESC hooked up to a R/C receiver and ran the motor up to 12200 RPM using with the ESC in its default setting.  Based on this I know that the motor, battery and prop combination should be able to reach 10200 RPM but when governing I do not seem to be able to get the right settings.

The ESC is set-up as follows:

Vehicle type           :  C/L
Throttle type          : Governor
Governor type       :  Set RPM
Initial spool up rate:  Medium
Head speed change: Medium
Governor gain        : Medium

Battery                   : 4S and the associated settings
Motor and gearing   :  1000Kv, 14 poles

Desired head speed:  10200 RPM on all three
PMW rate               : 16 khz

I have played with the PMW rate and tried the different governor types (high and low) and nothing seems to work.  Based on the instructions it seems that in governor low mode I should be able to go beyond 10K RPM but when I tested the RPM was limited to 6500.  On governor high, the RPM came at 12200.  In either case it appeared that the ESC was ignoring the desired RPM.  I also played with the pot on the timer to see if altering the throttle signal would have an effect; it did not.

Finally, I have been using the Castle B-link to do the programing as it would be what I would be using at the field if I needed to make any changes.  I have the option of using the normal Castle Link through a computer as well.

Hopefully there is someone out there who can point out my mistake.  At this point I am thinking that the easiest solution is to use a 10x6 prop so that the RPM would be under 10K.

Thanks,

Teo

Tim Wescott:
So you get 12200 RPM with an RC setup and the ESC in it's "default setting", then you change two things, and get 10000 RPM with the timer and the ESC set to governor mode.

What do you get with the ESC in governor mode and the RC setup?  Or the ESC in its default setting and the timer?

Teodorico Terry:
Tim,

When running the ESC with the timer it is always programed to run in governor mode.  Only when I tested it with the R/C receiver it was set to its default settings which allow for a linear throttle response (i.e. not governed).  I could try it in its default setting and see how it responds to the throttle signal from the timer's pot.

I also have a Jetti box so I could test timer output to see what signal it generates, I had assumed that with the pot it would vary in range as it would if using a receiver instead. 

None of my current set-ups go beyond 10000 RPM as my lowest pitched prop is a 5.5.  I am tempted to set-up one of the other systems to go above 10K to see if they can do it.  I am interested in testing a 12x5 prop so I will need to do it at some point.

Thanks,

Teo

Rick_Huff:
Teo,
I've run into the same problem with my twins.  Castle told me that there is nothing to lower the rpm at which they'll govern.  I found two solutions:  1.  Go to a very low pitched prop.  A 4" pitch prop worked for my twins, a 5" pitch did not.  2.  Replace the Talon 35 with a Jeti 33.  The Jeti doesn't seem to have this problem, or at least, it occurs at a much lower rpm.
I'm using 6s batteries, which may exacerbate the problem.  A 5" prop may work with the 4s system.
Rick

pmackenzie:
I would try regular governor mode, and see what RPM you can get from adjusting via your timer.(i.e not simple and not aet)
Try low and high.

But first step would be to do non-governor mode and a very small prop to make sure the system can actually get to the RPM you want.
Then try with the prop and make sure it can get there loaded. Ideally it should get to your target plus about 30% for good governor operation.

Since your timer just has a pot to set RPM, then set RPM mode makes sense. Make sure you have the pole count set correctly in Castle Link.
The ESC only knows electrical RPM, the pole count is needed to set the corresponding mechanical one. Most of the motors we use are 14 poles, but not all are.
(I don't recall if the Castle program talks about poles, or pole pairs?)

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