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Motor timing and the effect of it....?

Old 12-13-2009, 06:59 PM
  #1  
Norseman220
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Default Motor timing and the effect of it....?

Hi all.

I have just bought a electric setup for a Cessna 177 on floats, and I am wondering if anyone know what would be the better timing setting for my equipment.

Motor: Turnigy SK 50-55 580Kv with a 12x6 propeller
ESC: Turnigy Plush 80 AMP.
Battery: 6S Rhino 3700mAh 25C

The ESC is currently set to "mid" timing, and the power seems good, but I was wondering if anyone knows what setting the motor likes.
I get 10 min + flighttime as it is now if I fly with moderate throttle ..


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Old 12-13-2009, 07:40 PM
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flydiver
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Lower timing will be more efficient with less power. Higher timing will provide more power but less efficiency.
This is all predicated on actually working on these settings. Low will work most of the time. As you get higher there is a risk of getting the motor to 'backfire' if pushed too high.
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Old 12-13-2009, 07:43 PM
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Norseman220
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Thank you flydiver.

I think I'll just leave it as it is then, since the motor works great and the flighttimes are good.


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Old 12-13-2009, 10:21 PM
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nascarwings
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just my 2 cents....i run a couple of 50 55 580 s and the first set up was on a 80 amp esc on 5s and ended up smoking the esc because it was on low timing...i now only run them on hi timing ..
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Old 12-14-2009, 06:58 AM
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Norseman220
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Ok, thanks nascarwings.

Does that mean that a lower timing stresses the esc more?
Do you still run the same propeller you did when the esc fried?
And just out of curiosity, what propeller size do you use? and what RPM do you get..



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Old 12-14-2009, 07:12 AM
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flydiver
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Not sure what happened to nascarwings. Mere low timing should not burn up an ESC. I think there was some other issue going on (bad connection, bad component, over propped, etc.)

Electric motor timing is not dissimilar to car motor timing. As you increase the RPM it is more effective for the timing to be more advanced to coordinate with the magnetic rotation. In general lower timing is less stressful but there are always exceptions. That is a low KV motor and should be fine with low timing.

If you would like to learn a lot more about motor timing I suggest listening to Lucien Miller of Innovative Designs (Scorpion motors) on the ATTF podcasts. These 2 episodes specifically with associated time.
ATTF#114 at 33:20 Motor timing settings in ESC?
ATTF#71 at 44:15 Motor timing?
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Old 12-14-2009, 08:26 AM
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Moxus
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you also want to adjust timing according to switch frequency.
that is, if you got a high rpm motor with a high number of poles, you also want high timing (typical example is high rpm outrunner. edf application, or outrunner running with reduction gear in cars, helicopters or similar).
you want low timing for slower switching applications. that is inrunners for most applications, and outrunners running at modest rpm and power.
some inrunners might have more than 2 poles (i think mega uses that, but im not sure), they can be more outrunner-like when it comes to timing and switching.
the other exeption is very high rpm inrunners. for example extreme edf setups, or extreme hotliners/purespeed models with reduction gear.

if your model is working at modest rpm and modest power, you will ususally do fine with low timing, both for inrunners and outrunners.
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Old 12-14-2009, 10:40 AM
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nascarwings
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i dont know much about this but the set up i was running was a 50 55 580 kv on 5s with a 15 x 8 prop....i just cut this out of the 100 amp esc manual.
(WARNING: For some large motors, you must use High timing mode. Failure to do so will result in a burnt esc.) So not sure why but im sure someone will fill us in...all i can say is the 50 55 580 works great on hi and smoked my esc on low...
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Old 12-14-2009, 02:05 PM
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Norseman220
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Hehe.... Maybe I should try and read the manual.
Could be it contains some useful information........



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Old 12-14-2009, 07:36 PM
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flydiver
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Personally I think you had a lousy ESC.
What brand?
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Old 12-15-2009, 12:19 AM
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it was the 80 amp turngy i burnt up.....and iv been only running these ones now in my large planes http://www.hobbycity.com/hobbycity/s...(USA_Warehouse)... and if you read it, it tells you not to use low timing on larger motors...?
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Old 12-15-2009, 01:27 AM
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I've had good luck with Turnigy. So...not sure. The warning does just jump out at you.

I've got no experience with larger motors like that so it would appear that my experience either does not hold or not on this particular unit.

FWIW I've had a 2 Castle TBirds fail right out of the package and I consider Castle one of the top rated ESC's. Customer Service was almost shipping before I got off the phone so that was handled nicely.
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Old 12-15-2009, 02:38 AM
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Moxus
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larger motors will fall under the high power category, and be more itchy for high timing, at the same rpm level.

simplified, you can think of the switch frequency (sf) and power (p) as a product, wich must not exceed a limit.
so:
sf * p < max limit.

that gives you that more power means you must have less rpm before you start using high timing. vice versa, less power allows you to use higher rpm before you go to high timing.

that sf * p product is not linear, and also depends on your motor constants (inductance in coils), and that is unknown for most, if not all, hobby level motors.

so as much as i hate to say it, this high/low timing question is guesswork and guts feeling at best.
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Old 12-15-2009, 02:55 AM
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i think i can even make it easer...HI kv motor low timing.....low kv motor HI timing... some people say "inrunner" low, "outrunner" med - Hi
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Old 12-15-2009, 03:26 AM
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But that doesn't jibe with the 'general' fact that most inrunners are high KV and most (park flier type) outrunners are low(er) KV. The motor we are talking about here is supposedly 580KV, pretty low.
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Old 12-15-2009, 03:29 AM
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yes its low kv so it should be run on ..med to hi timing....
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Old 12-15-2009, 04:12 AM
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its all just brutal simplifications anyway, the true answer isnt possible to find since these motors dont come with complete datasheets.
so i think we have to settle for the solution we like best ourselves. coming to an agreement of the best solution, where textbook answers dont exist, is very hard.
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Old 12-15-2009, 07:56 AM
  #18  
Norseman220
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My ESC does not come with the same warning as Nascarwings do, and from what I understand it is ok to run my motor on mid timing like I do now......
OR do you recommend that I change it to HI???

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Old 12-15-2009, 09:14 AM
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Larry3215
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What timing you need very much depends on the brand and quality of the motor AND the esc.

With Castle controllers for example, you almost always run LOW timing on outrunners - even hi rpm and hi power setups. Inrunners, again with Castle controllers, usually do best on mid timing with hi timing used on some hi rpm setups.

Other controllers do things differently.

Kontronic, Schulze and some of the other quality brands have different settings that work best for THEIR controllers.

It largely depends on how the controller actually does the timeing. Castle controllers adjust the values dynamically as load and rpm change. Most of the cheep ones are fixed so your always going to have a compromise at some rpm/power setting.

In other words there is no fixed answer to "what timeing is best in what situation".

Best advice is use a watt meter and a tach and a temp gun. Adjust the timing to give you the best rpm/watt at a temp the motor - and controller - can survive...... or.... go with the mfg's advice
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Old 12-15-2009, 01:57 PM
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I'm really trying to follow this as I'm currently setting up a Senior Telemaster with a Turnigy SK 50-55 motor and Turnigy Plush 80A ESC.

The more I read though, the worse my headache is getting

Looks like I'll try medium timing at any rate. Kind of shooting for some middle ground here and trying to keep the "magic smoke" inside everything.

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Old 12-15-2009, 02:30 PM
  #21  
Moxus
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how many cells are you running, and what prop are you aiming for?
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Old 12-15-2009, 02:50 PM
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in my 8 senior i have the 50 55 580 15 X 8 on 5s it will haul it along nice....dont worry about the timing thing just dont use low timing on low kv motors...you can try it if ya want...it leaves a nice smoke trail...and make sure you disable the bec in the 80amp...and run a ubec or sep. rx pack...
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Old 12-15-2009, 05:31 PM
  #23  
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I think Larry has the overall perspective----it depends.

Here's some more confusing reading that attempts to shine a light on this issue:
http://homepage.mac.com/kmyersefo/timing/timing.htm

It has a link to a Castle article, very hard to find otherwise.

As stated, I can't speak to large motors. I have found the SAME motor will act VERY differently 'timing wise' on different brands of ESC. Some of my 1300-1700kv small (24g) motors will not run well on Hobbywing at low timing. They run fine on Castle though. Some folks don't like the way Castle starts up on small Chinese motors.

There is an older Castle Phoenix that has a known problem -quote from their FAQ site:

[4. I’ve heard the Phoenix 25’s are/were having problems with high wind, low kv outrunner motors. Is this true, and what is the definition of a “high wind, low kv outrunner”?
It is true that the old 1.5A BEC Phoenix-25’s started to have issues with high wind, low kv outrunners. This is the reason we redesigned the controller. This issue only affects 1.5A BEC Phoenix-25s. It does not affect any of our other controllers. A high wind, low kv outrunner is one that has a kv (rpm/volt) of approximately 1000 or less. If you have any questions regarding this issue contact tech support at [email protected] or give us a call at (913) 390-6939. We will be more than happy to answer any questions you may have.
]

So, I continue to be confused at a much higher level regarding ESC.
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Old 12-15-2009, 05:47 PM
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cliffh
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Originally Posted by nascarwings View Post
it was the 80 amp turngy i burnt up.....and iv been only running these ones now in my large planes http://www.hobbycity.com/hobbycity/s...(USA_Warehouse)... and if you read it, it tells you not to use low timing on larger motors...?
I just received my Turnigy Plush 80 amp esc and after going over the instructions, I cannot find anywhere where it says to "not use low timing on larger motors".

I just edited my post here. Your link goes to a 100 amp esc, not the 80 amp....completely different from my Turnigy Plush 80 amp esc. Guess that is the reason behind the different instructions.

Cliff
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Old 12-16-2009, 08:10 AM
  #25  
Norseman220
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This is a site that I used when deciding on my setup... I can't vouch for the accuracy of their measurements, but it seems like they have done a ok job. It's i French, but many people now have the possibility to translate....
Just click on the motor you are interested in..... Enjoy.

http://bungymania.com/bmdb.php

Steinar
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