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Old 05-01-2012, 09:16 AM   #1
urgno
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Default timing for yge80 + 3226-900 ?

hi,
on scorpion specifications there is: motor timing 5 degrees
is that correct for yge80 esc ?

on old 3026 I used 18 degrees with freewheel enabled
same parameters on 3226-900 give me a tail moving
could that be for the wrong timing ?

someone have a hint ?

thanks
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Old 05-02-2012, 02:18 AM   #2
dtabuenc
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I would run 18 degrees. I'm not sure why they put that figure on their website, maybe that's the timing that corresponds to their published KVs? If you want a more efficient motor (at the cost of some power) then run less than 18 degrees. You can pretty much always go down in timing without any worries (other than losing some power).

Please realize that timing isn't really controlling the actual timing. The ESCs use feedback from the motor to know when the optimal (most efficient time) to power up the motor coils is.

When you set timing advance you are telling it to offset from this optimum by a certain number of degrees. This will let the motor develop more power and actually raise the KV slightly (it will spin faster for the same voltage input). On the other hand it will cost you in terms of efficiency (both motor and ESC will run hotter) and you'll have shorter flight time.

Once you go beyond a certain point, you gain very little power for increasing timing at the cost of a lot of extra current draw. If you go further still, you will actually reach a point where you start losing power, or have weird motor issues or rough starts. This is because your offset is so large that it starts sort of intruding into a previous cycle.

Somewhere around 15-18% timing is a reasonable "happy medium" where you get good power without sacrificing way too much efficiency. There is no perfect timing setting for a particular motor though. "Perfect" timing is essentially no advance or 0 or "auto". But it will also give you the least power.

Feel free to experiment with timing. It's up to you whether you prefer most efficiency, most power, or something in between. You can probably safely try any value between 0-18, if you start going much higher though, be mindful of your ESC and motor temps. Make sure they are staying at reasonable levels.
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Old 05-02-2012, 02:23 AM   #3
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I missed the part about your tail moving. Timing will not affect the tail. Tail movement due to the ESC settings are usually related to governor gain being too high. In some very rare cases it can be due to PWM being too low. I doubt that's your issue but just in case you could try with 12khz instead of 8.
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Old 05-02-2012, 04:19 AM   #4
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Dude...whats the pole count of your motor...the what determines the required timing rate of the motor...the PWM is calculated using poles * volts* KV /20 that will give the correct Khz ...you match the ESC to your motor not the other way round...
I know motors that run at 8kz on Gov mode tend to oscillate at 50% throttle really badly but you need to make sure ( if you use gov mode) that the integral time is about 1/3 of the proportional gain .... just make sure you calc the PWM and use the correct frequency first then start playing with the timing.. if you get stuttering on spoolup your timing is way out..
4-6 pole motor likes about 7-8 degrees timing ...10-14 pole around 16-18 degrees but the voltage and KV will dictate the PWM...get the mix right and your motor runs cool and smooth...I've just done a lot of mucking around with YGE 120 and 160 ESC and different motors... my two cents worth..hope it helps.

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Old 05-02-2012, 11:24 AM   #5
dtabuenc
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Quote:
Originally Posted by Madryan View Post
Dude...whats the pole count of your motor...the what determines the required timing rate of the motor...the PWM is calculated using poles * volts* KV /20 that will give the correct Khz ...you match the ESC to your motor not the other way round...
The Poles * Volts * KV /20 calculates your electrical commutation frequency at full RPMs, but it doesn't necessarily tell you the best PWM. What you don't want to do is run your PWM way too low what the P*V*KV/20 formula finds. If the commutation frequency starts getting signifficantly higher (close to twice the PWM) it is a problem.

For the best efficiency you want the lowest PWM that will run your motor smoothly. Higher PWMs won't ever hurt the motor, but they will put more strain on your ESC. Most motors in our helis will run fine at 8khz due to their high inductance. When unsure though, it's always safe to try 12khz. Much more than that is usually unnecessary unless your motor is both very high pole count and high KV.

For those motors you can use the (P*V*KV)/20 to get an idea of the minimum PWM you should run. For example, for your motor the formula calculates 9.9KHZ. This is just a little over 8, so 8 could probably run just fine. If it doesn't you can try 12. If the formula had given you 15 or 16khz then it wouldn't work very well at all with 8khz PWM but might work fine at 12.



Quote:
Originally Posted by Madryan View Post
I know motors that run at 8kz on Gov mode tend to oscillate at 50% throttle really badly but you need to make sure ( if you use gov mode) that the integral time is about 1/3 of the proportional gain
Usually tail oscillations will be caused by too high proportional or overall gain. Only after pulsing and gear chatter is eliminated should you mess with the integral part.


Quote:
Originally Posted by Madryan View Post
4-6 pole motor likes about 7-8 degrees timing ...10-14 pole around 16-18 degrees
Those are reasonable rules of thumb, but keep in mind "0" timing will always work regardless of the motor. You can increase from 0 as much as you want until you get the balance of power/efficiency you need. A beginner can run their timing on 0 if they want to get extra flight time since they don't need a lot of power. Someone who wants more power can chose to run 15 degree timing on a 6 pole motor instead of 7-8 to get the extra power at the cost of efficiency. There is no set rule, it's user preference. The values you give are a reasonable ballpark for a good balance of power and efficiency.


Quote:
Originally Posted by Madryan View Post
get the mix right and your motor runs cool and smooth...I've just done a lot of mucking around with YGE 120 and 160 ESC and different motors... my two cents worth..hope it helps.
Getting the motor to run smooth and cool is pretty simple. Just set high PWM and low timing (although high PWM will make the ESC run a bit hotter). Raising the timing from 0 will always make the motor run hotter. The choice one makes by running higher timing is how hotter we are comfortable getting in exchange for more power.

Those who want the absolute best power and don't care about efficiency would raise the timing all the way up until you get commutation problems and chirping and then back off a bit. This would give you the most amount of power, but your efficiency and flight times would be really low.
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Old 05-02-2012, 10:17 PM   #6
urgno
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thanks for all replies... very interesting

PS. here the complete specifications of that motor:
Code:
Stator Diameter 	32.0 mm (1.26 in)
Stator Thickness 	26.0 mm (1.02 in)
No. of Stator Arms 	12
Magnet Poles 	10
Motor Wind 	9 Turn Delta
Motor Wire 	23-Strand 0.23mm
Motor Kv 	900Kv RPM/Volt
No-Load Current(Io/10V) 	2.21 Amps
Motor Resistance (Rm) 	0.019 Ohms
Max Continuous Current 	60 Amps
Max Continuous Power 	1770 Watts
Weight 	239 Grams (7.77 oz)
Outside Diameter 	40.9 mm (1.61 in)
Shaft Diameter 	4.98 mm (0.19 in)
Body Length 	50.5 mm (1.99 in)
Overall Shaft Length 	75.5 mm (2.97 in)
Max Lipo Cell 	8s
Max Peak Current 	75A (2 seconds)
Max Peak Power 	2220 Watts (2 seconds)
Motor Timing 	5deg
Drive Frequency 	8kHz
my first try to solve tail oscillation was to use "auto timing" on esc with pwm 8khz

i think i will try turning off the governor to see if is the cause of tail oscillation
then look if could be for static or something mechanical
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Old 05-03-2012, 12:38 AM   #7
dtabuenc
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Quote:
Originally Posted by urgno View Post
thanks for all replies... very interesting

my first try to solve tail oscillation was to use "auto timing" on esc with pwm 8khz

i think i will try turning off the governor to see if is the cause of tail oscillation
then look if could be for static or something mechanical
Yeah, timing will likely never cause tail oscillations. Low PWM can but in rare circumstances and likely not on that motor since it claims to work fine at 8khz. Keep in mind that you can always run higher than 8khz without adversely affecting motor performance (although the esc will run a bit hotter).

Is there a reason you think the tail issue is ESC related? Is it possible there is something wrong mechanically or on your heading hold gyro?
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Old 05-03-2012, 04:33 AM   #8
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i think to try first the governor because is the easiest thing to change with progcard ;-)
the tail not only slowly oscillates but sometime give also a little kick
so maybe could be static issue

the model is protos 500 stretched fbl with beastx
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Old 05-03-2012, 07:36 AM   #9
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What tail servo? My Protos tail is rock solid with DS650 and BX. But my B400 has some oscillation occasionaly. Small wags with side wind, and a wag on pitch pump I can't get rid of. Might be tail servo speed? I'm running a .05sec Hyperion on the blade tho
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Old 05-03-2012, 07:47 AM   #10
urgno
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i have mks 9670 on tail ... on the other protos identical to this one works perfectly
(the only difference is the scorpion and esc)
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