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Old Jul 15, 2003, 04:09 PM
Flys with Thumbs
Danal Estes's Avatar
Frisco, TX, USA
Joined Sep 2001
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Governor Mode Myths

Over in electric heli, governor mode gets discussed a lot. There are some common things popping up that I believe to be myths. But, opinions vary, so let's enlist our resident Speed Controller experts, if they are willing.

I'm going to attempt to post a few widespread, repeating, statements that I believe are untrue. If I summarize wrong in such a way that they cannot be answered by CC, please let me know... I'll try a re-phrase.

Unless otherwise specified, I'm always asking in the context of electric helicopter usage.

So, here goes:



Governor Mode Myth #1:

You must use a throttle setting of 100% in governor mode. Anything less means you are giving up 'headroom' - that is, wasting some percentage of the total pack/motor system's capability to generate power.


Governor Mode Myth #2:

Never run a governor over about 85 to 90% throttle. The governor needs the remaining percantage to allow it to respond to load without bogging.


Obviously, these are in conflict.... but both are often repeated. What's the real scoop CC?
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Old Jul 15, 2003, 06:00 PM
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Perfect questions. Very confusing stuff!

-- Gary
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Old Jul 16, 2003, 02:50 PM
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JohnM's Avatar
Providence, RI, USA
Joined Dec 1996
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My setup is a Mega 16/15/3, CC Phoenix 45, Robbe Eolo heli.
If I run my CC P45 in governor mode at 100%, the rpm will not increase when the pitch is increased. Since the rpm is already at the maximun, it can't go any faster to compensate for the increase in pitch.

If I run my CC P45 in governor mode at 75%, the headspead will stay constant when the pitch is increased (until the motor bogs).
The rpm increases when you add pitch similar to cruise control when a car goes up a hill. The motor rpm increases but the speed of the car is held constant.

I prefer this over the above (100%) setting.

John
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Old Jul 17, 2003, 12:58 PM
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Chicago
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JohnM-did you mean "power increases and rpm stays constant"?
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Old Jul 17, 2003, 08:40 PM
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Patrick del Castillo's Avatar
Olathe,KS,USA
Joined Oct 2000
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Re: Governor Mode Myths

Quote:
Originally posted by Danal Estes
Over in electric heli, governor mode gets discussed a lot. There are some common things popping up that I believe to be myths. But, opinions vary, so let's enlist our resident Speed Controller experts, if they are willing.

I'm going to attempt to post a few widespread, repeating, statements that I believe are untrue. If I summarize wrong in such a way that they cannot be answered by CC, please let me know... I'll try a re-phrase.

Unless otherwise specified, I'm always asking in the context of electric helicopter usage.

So, here goes:



Governor Mode Myth #1:

You must use a throttle setting of 100% in governor mode. Anything less means you are giving up 'headroom' - that is, wasting some percentage of the total pack/motor system's capability to generate power.


Governor Mode Myth #2:

Never run a governor over about 85 to 90% throttle. The governor needs the remaining percantage to allow it to respond to load without bogging.


Obviously, these are in conflict.... but both are often repeated. What's the real scoop CC?


OK, I think several things are being misunderstood ... let's see if I can clear things up a bit.

First of all, the percentage of throttle on the STICK doesn't have anything to do with % of throttle at the motor when in governor mode. The stick (or throttle%) from the radio commands the controller to a given RPM -- the controller will determine how much throttle is required to maintain that RPM, and will modulate the throttle accordingly.

For example -- in Governor Mode 1 (low RPM mode) the motor speed range is approximately 12000-36000 on a two pole motor (like a Hacker) or 6000-18000 on a four pole motor (like an Neu) or 4000-12000 RPM on a six pole motor (like a Mega.) So if you set a 50% throttle point on a Hacker motor, the controller will set the throttle automatically to run at 24000 RPM. If you are running a high RPM hacker motor (Like a B20-12L) with no load, the controller might only have to use 10-12% of throttle to maintain that RPM. Under load, it might take 50% throttle to maintain that RPM. If you put a really big load on the motor, the controller will go to 100% throttle to try to maintain the 24000 RPM point.

A good illustration of Governor mode can be made by using a motor with no load. If you run the motor up, and then put a finger against the motor shaft to load it up, you will notice that the motor (for a brief period of time) will slow down, then the controller will increase throttle to compensate, and the RPM will return to the set point. When you then unload the motor, it will (again for a brief period of time) increase in RPM, and then the controller will reduce the throttle to bring the RPM back to the set point.

The idea is that a constant head speed (regardless of collective setting) is desirable. The controller will increase throttle automatically when the collective is increased, and decrease throttle automatically when collective is decreased, in order to hold the head speed constant.

Does that make sense?

Patrick
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Old Jul 17, 2003, 08:44 PM
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Yes, thank you, that is a huge help.
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Old Jul 18, 2003, 08:28 AM
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Patrick --

In your example above, what happens to the RPM ranges if you change the number of cells? If you are using 5s LiPos and then go to 6s (or you go from say 18 cells, say, to 20 cells of NiCds...) does the RPM range increase?

-- Gary
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Old Jul 24, 2003, 12:43 PM
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GGoodrum -- No, the RPM range will remain the same regardless of the input voltage. However, the maximum RPM that the motor will be able to sustain will (of course) increase, so you will see an increase in the MAXIMUM controllable RPM. If, however, you increase the cell voltage, but use the same setting (throttle %) you will still have exactly the same RPM out.

Now this brings up a good point that I didn't address earlier -- as you increase the input voltage, the motor will have to run at lower throttle to maintain the same RPM. In some cases, this can be very hard on the motor and controller, especially when the throttle % goes below 60% or so. It's better to change the pinion gear when increasing voltage in order to allow the motor to run closer to it's no load RPM.

Patrick
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Old Jul 24, 2003, 03:30 PM
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I am going to link this to the Heli Forum.

Things are becoming clearer and needs to be sured.
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Old Jul 24, 2003, 04:47 PM
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Mississippi 31 years , Now Kotzebue , Alaska 12
Joined Apr 2001
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so , what with the rappy runing at 100% gov mode and getting 1 minute longer flight time and a headspeed staying constant with no bogging , seams to me that all electric motors like where I work at run best at there giving motor rpm value , 100% and gear it from there , that is if you have the right kv motor for the giving application or heli and gearratio , Tony
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Old Jul 25, 2003, 12:57 AM
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Oh Oh.... I hope I did not do a bad thing I jumped to this thread from a link in the heli forum. Not knowing "where I was" and that this was a vendor-specific thread, I just PM'd Ulf Herder, who worked on the the Schulze Future design and probably others over a period of years, and asked him to offer his comments here.

I'm sorry, but I guess I might wonder why this general topic would be posted here anyway.

Cheers!
Glen Peden
http://www.logoheli.com
Visit the LOGOmaniac Forums
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Old Jul 25, 2003, 02:01 AM
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South Orange County, CA
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Okay, I think I know how it is suppose to work but I'm still getting ESC shutdowns with the Phoenix 60 in my Logo 10 when it is in the governor mode. I had the NORMAL mode set to a max of 80%, which gave me a headspeed of about 1650. I have a dedicated fan, just for the controller, but still it will shut down after just a couple of minutes, forcing an autorotation.

Would it run better if I either set the limits to 100% or if I disabled the governor mode?

-- Gary
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Old Jul 25, 2003, 03:15 AM
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Germany, HE, Schauenburg
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Quote:
Originally posted by GGoodrum
Okay, I think I know how it is suppose to work but I'm still getting ESC shutdowns with the Phoenix 60 in my Logo 10 when it is in the governor mode. I had the NORMAL mode set to a max of 80%, which gave me a headspeed of about 1650. I have a dedicated fan, just for the controller, but still it will shut down after just a couple of minutes, forcing an autorotation.

Would it run better if I either set the limits to 100% or if I disabled the governor mode?

-- Gary
Hi Gary,

for the optimal answer you should post all important data:
1. Which motor?
2. cell count(and type)?
3. Pinion?

Regards,

Ulf
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Old Jul 25, 2003, 03:23 AM
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Joined Dec 1996
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Quote:
Originally posted by gpeden
Oh Oh.... I hope I did not do a bad thing I jumped to this thread from a link in the heli forum. Not knowing "where I was" and that this was a vendor-specific thread, I just PM'd Ulf Herder, who worked on the the Schulze Future design and probably others over a period of years, and asked him to offer his comments here.

I'm sorry, but I guess I might wonder why this general topic would be posted here anyway.

Cheers!
Glen Peden
http://www.logoheli.com
Visit the LOGOmaniac Forums
Hi Glen,

I have read the explanations from Patrick some messages before, which were a good description how a controller in the governor mode works.
I add a very important hint:

Never use a headspeed less than 20% lower than the maximum headspeed you can reach at full pitch.

Best Regards,

Ulf
PS: I will post more this weekend.
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Old Jul 25, 2003, 09:03 PM
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Ulf, Did you mean to say in your hint "the maximum headspeed you can reach at full pitch" at full throttle?

I can't imaging a case in which one would want to set his controller governor to an rpm less than that at full load.

Patrick: What does the controller in governor mode do with 100% throttle command from the receiver as the load varies?

Hank
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