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Electric Stunt => Gettin all AMP'ed up! => Topic started by: ericrule on August 23, 2014, 08:18:07 PM
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I was attending a contest last week end and saw a fellow having problems with his ECL. the motor would start and run up fine then stop suddenly. Fortunately he got it going again and was able to complete his flight. After he finished I asked him what happened.
Well, it turns out that he had changed the settings in his ESC. what he did was to turn on the slow start feature in the ESC. The only problem with this action is that he was running a KR Governor. The KR Governors come with a built in slow start!
In electronics you simply can not have two components trying to control the same function. Since the KR Governor already has a slow start in it you must allow it to control that function. If the KR Governor is trying to slowly rotate the motor shaft over a 2 second time frame and the esc is trying to do the same thing they "fight".
The KR Governor works by measuring the width of the emp pulse as the motor shaft rotates anything that causes that band width to change will be read by the governor as an external force attempting to stop the motor shaft. As soon as the KR Governor sees this it will instantly shut down the motor to protect it from excessive amperage flow (that's what burns up the motor, esc & battery when you have a prop strike).
If you are using a KR Governor DO NOT TURN ON THE SLOW START FEATURE IN YOUR ESC.
Eric Rule
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Eric,
I am not sure the cheep speed controller I have even has slow start. LL~ That's one of things I love about my KR timer - it works with inexpensive speed controllers.
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Good Morning John;
I suppose it depends on one's definition of 'cheap'. I know my ZTW A-series ESC's (<$30) do have a slow start-up function, and in fact I ended up writing to Keith with this very question during initial programming/ configuration.
Always best to check any documents provided, and heed the guidance provided by Eric.
r/
Dave
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Good Morning John;
I suppose it depends on one's definition of 'cheap'. I know my ZTW A-series ESC's (<$30) do have a slow start-up function, and in fact I ended up writing to Keith with this very question during initial programming/ configuration.
Always best to check any documents provided, and heed the guidance provided by Eric.
r/
Dave
You'r right of course. Mine is a Turnigy and one of the program choices is start mode. I guess the default is normal start. I have never set it and it works.
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Hi John:
If it works don't change anything!!!
Quite often the lower priced ESC's have factory set defaults that basically turn off everything. Since the KR Governor runs everything that seems to work quite well for us.
A lot of the Turnigy ESC's are manufactured by ZTW (they are one of the largest manufacturers in China).
Eric
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With the KR timer,I never even considered messing with ESC settings, and everything works! You want egg in your beer? (Yuck) >:D
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I was attending a contest last week end and saw a fellow having problems with his ECL. the motor would start and run up fine then stop suddenly. Fortunately he got it going again and was able to complete his flight. After he finished I asked him what happened.
Well, it turns out that he had changed the settings in his ESC. what he did was to turn on the slow start feature in the ESC. The only problem with this action is that he was running a KR Governor. The KR Governors come with a built in slow start!
In electronics you simply can not have two components trying to control the same function. Since the KR Governor already has a slow start in it you must allow it to control that function. If the KR Governor is trying to slowly rotate the motor shaft over a 2 second time frame and the esc is trying to do the same thing they "fight".
The KR Governor works by measuring the width of the emp pulse as the motor shaft rotates anything that causes that band width to change will be read by the governor as an external force attempting to stop the motor shaft. As soon as the KR Governor sees this it will instantly shut down the motor to protect it from excessive amperage flow (that's what burns up the motor, esc & battery when you have a prop strike).
If you are using a KR Governor DO NOT TURN ON THE SLOW START FEATURE IN YOUR ESC.
Eric Rule
So how do you shut it off when it starts at 10%?
Or is there an update to these settings?
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Kevin;
From your comment I am assuming that you are referring to the ESC setting. Depending upon the brand of ESC you are using just get a program card and change the ESC settings.
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Kevin;
From your comment I am assuming that you are referring to the ESC setting. Depending upon the brand of ESC you are using just get a program card and change the ESC settings.
ZTW Starts at 10% Can't turn it off.
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Kevin;
If your ZTW ESC is black in color it is one of the older Air series. In order to change the setting all you need is to get one of the pin style program cards. If you ESC is green it is the newer Mantis series. For that one you will need the LED Program card. Both styles of program card are available at RSM.
With either program card it only takes 30-40 seconds to change any or all of the settings.
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:-[
Green ZTW
Have program box
Slow Start up starts at 10% Step #8
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Programmable Options:
1) Brake setting (off/soft/mid/hard -- default: off) * Change to Hard #4
2) Battery type: (Ni-XX/LiPo/LiFe -- default: LiPo auto detect) #2
3) Low voltage cutoff setting (2.8V / 3.0V / 3.2V / None -- default: 3.0V) # 1
4) Factory default setup reset Timing settings (auto / 2° / 5° / 8° /15° / 22° /30° -- default: auto) #1
5) SBEC output voltage (on 45A and larger models only) (5.0V / 5.5V / 6.0V -- default: 5.0V) #1
6) Governor mode (RPM off / 1st soft start / 2nd soft start / gov mod 1 / gov mod 2 -- default: RPM off) #1
7)Motor rotation (forward / reverse -- default: forward) * Change to Reverse if using a pusher prop #2
8)Start-up strength (10% / 15% / 20% / 25% / 30% / 35% / 40% / 45% / 50% -- default: 30%) * Change to 50% #9
9) Low voltage cutoff type: (reduce power / cut-off power -- default: reduce) #1
How to Use the LED Program Card:
1.ZTW Program card with LED display is easy to use and convenient to carry. All of the programmable functions are shown on the program card.
2.Turn on the ESC. Remove the signal wire and plug it into the top-socket on the program card, wait for 2 seconds until the LED is on.
3.If ESC is not connected with the batteries, the program card should be connected with other power supply, the range of power supply is from 5.0V to 6.3V.
4.Press the button ”Menu” on the program card and circularly select each programmable function. At that time the number of programmable function will be displayed on the left of the LED, the current value will be displayed on the right side. Then press the button “Value” to change the value and press the button “OK” to confirm. At the same time the Red indicating LEDs of both program card and the ESC will blink. Turn off the ESC, the modified settings will be saved in the ESC`s memory.
5.Press the button “Reset” to restore the default settings.
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HB~> Never Mind. Sorry I asked such a simple question that can't be or wont be answered.
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HB~> Never Mind. Sorry I asked such a simple question that can't be or wont be answered.
It looks as if you need to set the Governor mode to #1 - RPM Off (by Eric's post above)
That should put the ESC in fast start and no RPM control. With MOST ESC's, this will disable the slow start feature, but ..
Also set the "Start up strength" to 50% (also per Eric's post).
Then the KR Timer can control the spool up and the governing function.
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It looks as if you need to set the Governor mode to #1 - RPM Off (by Eric's post above)
That should put the ESC in fast start and no RPM control. With MOST ESC's, this will disable the slow start feature, but ..
Also set the "Start up strength" to 50% (also per Eric's post).
Then the KR Timer can control the spool up and the governing function.
Thank You
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Like Mike said.
I only posted the data on the ESC settings in case you had not read the manual or did not know which settings were needed or how to make the changes on your LED Program Card. I though you might like to download the data for future reference.
Sorry if you thought I was not answering the question.
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Like Mike said.
I only posted the data on the ESC settings in case you had not read the manual or did not know which settings were needed or how to make the changes on your LED Program Card. I though you might like to download the data for future reference.
Sorry if you thought I was not answering the question.
Thanks Eric, I didn't know that step #6 Controlled Step #8.So you can see why I am confused as to How to disable Slow Start-up when it starts at 10%.
I am trying to learn as to what each setting will do as in change performance. I am not one that cares for the easy "Just Set It This Way" and be done with it. I prefer to know "Why" it is set that way.
So why then is step #8 set to 50% instead of 10% if it is to be disabled? So that brings back Does Setting #6 Actually Control Step #8?
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The setting in feature 6 doesn't affect setting 8. They are two different things. Soft start is the amount of TIME it takes for the motor to be ramped up to the commanded speed. In RPM off, there is no ramp up. The ESC tries to instantly run the motor at whatever speed is commanded. In Soft Start 1, the ESC stretches out the time to reach the commanded RPM to 8 seconds. In Soft Start 2, it stretches out the time to 18 seconds. In either Governor mode, it is 23 seconds. These parameters are called out in the ZTW manual, and may or may not apply to other brands. This slow ramp up is to keep from stripping gears in helicopter rotor power trains.
You want to use "RPM Off" (or "Airplane" mode) because the KR Timer has it's own built in ramp up and if the ESC slows the ramp up, it will look like a prop strike or some other mechanical interference to the KR, and it will shut down.
Setting 8 is startup POWER, the initial current supplied to the motor by the ESC. There is no real explanation of this in the manual but it is unrelated to the Soft Start feature and apparently you can set it to the highest value - 50%. You can set it as high as it will let you. I don't also understand why it only goes up to 50%. I assume it is some other helicopter specific parameter for some safety feature which probably doesn't apply to our uses. I also don't know how quickly the ZTW ramps up to full current, but it must be fairly quickly or it would confuse it's own internal governor.
In any case, the major consideration here is to have the KR being solely in control of RPM, and to have the ESC react instantly to the KR's commands, and that is accomplished by using setting 1 in the Governor section.
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By Golly now that is exactly what I wanted to know. Thanks Mike, Now I get it.
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I've been trying to find out more about the "Startup Strength" parameter mentioned as Setting #8. The ZTW ESC manual gives little information regarding what behavior this might effect. I use a lot of the YEP (rebranded YGE) ESC's in my Navy Carrier electrics and remembered that the programming card for these has a similar setting that can be changed. I found in the YEP manual this description:
StartupPower. The higher the startup power, the faster and harder is the start. With small propellers it isn’t a problem, but with large ones, it can lead to a fairly rough startup behavior.
The YEP has a similar range of values to choose from, but also has an "Auto" setting, which is where I always have run mine.
So it seems that if your prop chatters on startup, you would select a lower value of startup power to smooth the startup. And this would primarily present itself when using props on the larger end of the spectrum.
Perhaps on a related note, I have one stunt/sport setup that is using a Castle Phoenix in 'Simple Governor' mode, with a Hubin FM-9 timer. This one chatters and kind of rattles back and forth and sometimes never gets going in the right direction and after 3 or 4 seconds, it just quits trying. If you give the prop a spin just before it starts up, it gets going without much trouble. It's the one electric I have that ALMOST always gives me one-flip starts.
I think I will go into the Castle programming and see if there is some "Startup Power" type of change I can make.
UPDATE: In an effort to gain some insight into this, I hooked my plane up to the Castle Link and found 2 settings that I think may affect the startup, at least for the plane I described. Before I began, I tried 5 or 6 starts and only successfully spooled up 3 times. In the Castle Link software is an "Initial Spool Up Rate", which appears to be analogous to the 'Soft Start' Settings and can be set from 1-20. Mine was set at 20, which I assume means 20 seconds. I adjusted it to 10. There is also a "Startup Power" setting which appears to be analogous to the ZTW's 'Startup Power'. Mine was set at 100. I adjusted it to 59. I got 5 consistent proper starts with no failures. It appears that having the initial power too high can cause an issue with the startup sequence. Keep in mind that this plane does NOT use a KR timer, but relies on the Castle internal Governor function. This whole exercise was more of an effort to learn what the terminology referred to.