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Author Topic: Ztron and ESC program variables  (Read 1612 times)

Offline John Witt

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Ztron and ESC program variables
« on: November 18, 2009, 09:36:11 AM »
My apologies in advance if this has been covered before.

I have just made the first few flights with my Vector 40 and the ICE 50 ESC. I'm using a Ztron CLT3 and have the start and end throttle settings at 50% pulse width.

The ESC is programmed for SET RPM mode at 9100 RPM for all three speed ranges, medium spool up.

The data from the ICE shows that the RPM is not being maintained under load, dropping about 400 RPM. The question is if the 50% throttle settings leave the ESC room to add power to keep the RPM contant under load, or are these settings limiting the ESC.

The airplane is certainly slowing down in the maneuvers.

I've used these settings successfully in my Panther but with the Phoenix 45 ESC, and before updating to the latest software revisions.

John W
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John Witt
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Offline Jason Greer

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Re: Ztron and ESC program variables
« Reply #1 on: November 18, 2009, 10:16:09 AM »
John,

The motor power out % data point will show if you are hitting 100% throttle when the load increases.  You will have to enable that parameter and add it to the graph also.  I found that I am hitting about 93% towards the end of the flight with my setup, but the RPM does not fluctuate very much. 

Jason
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Alan Hahn

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Re: Ztron and ESC program variables
« Reply #2 on: November 18, 2009, 11:17:03 AM »
I think your motor kV is too low for that battery and rpm.

My suggestion is to put on a higher pitch prop that will get your target rpm in the 8500 rpm range.

I'll check your setup in the sticky to see what you are currently using.

added after----I don't see the Vector setup, but if I assume it is the same as the 2nd Panther setup (motor kV=800 rpm/volt), then I think my original guess is right.
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Offline Igor Burger

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Re: Ztron and ESC program variables
« Reply #3 on: November 18, 2009, 11:22:41 AM »
looks like too low kv

did not we write that those numbers somewhere at 800 is too little some weeks ago?

you can see it easy, if you feel rpm drop at end of flight worse and worse, then it is that problem
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Offline John Witt

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Re: Ztron and ESC program variables
« Reply #4 on: November 18, 2009, 11:52:24 AM »
Thanks for the response.

 The prop is 10.5-6, cut down 12-6 APC, or I also have a MAS 10-7 three blade. The motor kV is 800. 4S pack so for 14.5V * 800 = 11600 RPM. I thought that should be plenty of headroom.

However, the plot shows the motor rpm and voltage declining exactly together.

John W
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John Witt
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Alan Hahn

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Re: Ztron and ESC program variables
« Reply #5 on: November 18, 2009, 12:25:54 PM »
Quote from: John Witt on November 18, 2009, 11:52:24 AM
Thanks for the response.

 The prop is 10.5-6, cut down 12-6 APC, or I also have a MAS 10-7 three blade. The motor kV is 800. 4S pack so for 14.5V * 800 = 11600 RPM. I thought that should be plenty of headroom.

However, the plot shows the motor rpm and voltage declining exactly together.

John W

I see from your first post that you said you used these settings with your Panther---does that mean you ran the same prop and motor on the Panther at 9100 rpm with no problem? If so then there is something strange going on---and if the two motors are physically different, then I would suspect the kV is off on at least one of them.

My suggestion is to cut the prop down to ~11.5" and try with a lower rpm. As I have mentioned, I fly my Vector with a full size APC 12-6 at 8000 rpm (Scorpion SII-3020 with kV=780 rpm/V) . Somewhere between 12" and 10.5" should be a happy point!  y1

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Offline Igor Burger

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Re: Ztron and ESC program variables
« Reply #6 on: November 18, 2009, 01:37:43 PM »
And what is the internal resistance of that motor?
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Alan Hahn

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Re: Ztron and ESC program variables
« Reply #7 on: November 18, 2009, 01:55:11 PM »
I'll make a comment--when I look at that motor in DriveCalc, someone has entered some measured rpms/voltages/amps, and DriveCalc calculates a kV of ~700 rpm/Volt. I can't vouch that John's is the same, but it might be worthwhile to make a kV measurement.

To do that, take the ICE out of governor mode and set the timer throttle to 100%. Remove the prop and start it up. Look at the data, and kV is basically just the rpm/volts of any time slice in the plot.
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Offline John Witt

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Re: Ztron and ESC program variables
« Reply #8 on: November 18, 2009, 02:07:27 PM »
Good idea, Alan. I have no actual data for the Panther, since I just got the ICE 50 for the Vector. Could be the same thing going on there without me being aware of it. Also, with the Panther I was running a 12-6, since it has more ground clearance.

Another point is that I have 14 poles entered in the ESC program because that's what I counted. I could be wrong about that which would put the ESC data in doubt. I noticed in recent Hobby City catalog, that they now show that motor as a 900 kV being the lowest kV available.

I'll see if I can make time for the measurements today or tomorrow. I'm on vacation so I'm incredibly busy.

John W
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John Witt
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Alan Hahn

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Re: Ztron and ESC program variables
« Reply #9 on: November 18, 2009, 02:58:19 PM »
John,

I am pretty sure that 14 poles (=# magnets in motor shell) is correct.

I think that there is some variability in the Turnigy line (=QC). On cheaper motors  the kV is sometimes higher, since weaker magnets, or fewer # of winds will give a higher kV. I think lower is more more unusual.
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Online Dennis Adamisin

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Re: Ztron and ESC program variables
« Reply #10 on: November 18, 2009, 09:45:21 PM »
John, didn't you have a problem with your Panther this way too?  I do not use Z-Trons but I thought someone pointed out something about enabling 100% throttle (per Jason's suggestion)

Posibbly part of the smoking gun is I notice your RPM's never go ABOVE 9100 rpm either - as if it was artificially limited...

Of course, cannot rule out the bad motor or timer - can you swap components out of the Panther to cross check?
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Offline John Witt

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Re: Ztron and ESC program variables
« Reply #11 on: November 19, 2009, 01:50:02 PM »
The ESC is in SET RPM, so the motor should maintain 9100 rpm. What I'm looking for is the reason it won't maintain 9100.

I think the discussion you are referring to with the Panther was why it flies better with the timer set to 50% throttle instead of 100%. This set up was in response to Paul's suggestion that he had found that it worked better that way. I don't think anyone ever arrived at why this is so.

Wish I had some flying weather. It is raining like mad here, does the weather think we are Chicago? Oh well, lots of building on the Jenny.

John W
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John Witt
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"Houston, Tranquillity Base here. The Eagle has landed."

Offline Jason Greer

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Re: Ztron and ESC program variables
« Reply #12 on: November 19, 2009, 02:57:18 PM »
John,

I am running SET RPM mode in my ice 50 as well.  In SET RPM mode the esc will increase or decrease the throttle position to maintain the rpm depending on the load placed on the motor.  You can see the extra data point in my log file below showing the motor power out %.  Its the blue line on the graph.  You can see it flucuate depending on the load.  If the voltage drops too low during the flight then the throttle will hit 100%.  As a result the rpm's start to drop since there is no more room to increase the throttle.  Hope this helps.

Jason 

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Alan Hahn

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Re: Ztron and ESC program variables
« Reply #13 on: November 19, 2009, 03:18:24 PM »
Jason,
I really need to get my ICE 50 soldered up!

I note that you have some correlated rpm variations. Have you tried to juice up the gain a bit to eliminate them? I haven't seen any on my EagleTree and I think I am running a relatively "medium" gain. I am certainly curious to compare my EagleTree to the ICE 50 readings to see if there is any difference.
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Offline Jason Greer

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Re: Ztron and ESC program variables
« Reply #14 on: November 19, 2009, 03:44:07 PM »
Alan,
I did notice the rpm fluctuations.  I cant remember off the top of my head what my gain is set at, but I believe I have it set around 25.  I will double check when I get home from work.  I dont have my backup configurations saved on my work laptop.  I am interested in how your eagle tree data compares to the castle logs also.  I wish the ICE had a bit more storage space for logging.  I can only get one flight logging the data you see in the graph.

Jason
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Offline Jason Greer

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Re: Ztron and ESC program variables
« Reply #15 on: November 20, 2009, 07:09:30 AM »
I checked last night and my gain is set to 23.  How much gain are you guys running?

Jason
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Offline John Witt

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Re: Ztron and ESC program variables
« Reply #16 on: November 26, 2009, 09:40:56 AM »
I had a chance this morning to set up the Vector and measure the kV. Turned out to be 749, so it is somewhat lower than expected (800 is the spec when I bought the motor). Here's the download.

I'm shooting for maintaining 9100 to hit the speed I want (5.2 sec lap) with the 10.5-6 prop.

I have a 13-6.5 I can cut down, that would be my next choice if I have to run a lower RPM.

John W
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John Witt
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Alan Hahn

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Re: Ztron and ESC program variables
« Reply #17 on: November 26, 2009, 11:26:15 AM »
John,
I'd just go with 11" diameter prop (since I think you are cutting down from a 12" prop). To give you the target, I am flying ~5.1s laps at 8000 rpm on a 12-6 (tractor) stock APC TE prop. So if you want to hit 8600, just cut a little less.
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