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tworst · 02-25-2012, 06:10 PM

Does a governor actually control motor speed? That is, as the flight pack voltage decreases during flight, will the govenror try to maintain a constant relationship between radio commanded speed and actual head speed. So, at 90% commanded speed, it will maintain that speed regardless of the flight pack voltage. I am talking about an ESC or maybe an FBL like the VBAR. I know that the ESC/VBAR with a phase sensor can monitor the headspeed, but can it actually compensate for drop in voltage of the flight pack?

flerpie · 02-25-2012, 11:25 PM

Yes, they compensate for pack voltage. But they may not actually know
what the pack voltage is. Doesn't need to. All it needs to know is what the
target RPM is supposed to be (in settings) and what the headspeed
actually is. Then it widens or narrows the motor driving pulses in an
attempt to keep the headspeed where it should be. As pack voltage falls
it will widen the pulse, effectively providing more current to the motor to
keep the speed up.

Perhaps some of the better governors actually do monitor pack voltage
as part of the governing process...kontronic and YGE, maybe VBar.

But the point is that knowing what the pack voltage actually is
is not a strict requirement of the governing process.
But probibly helps if the added sophistry is designed in.
All just depends on the govenor design is all.

tworst · 02-26-2012, 09:28 AM

OK, thats kind of what I thought. I realize that actually knowing the pack voltage is not required although it could be usefull for gain compensation to get the same transient response. The motor speed is controlled by a PID feedback loop with the phase sensor (for VBAR) as the process variable and the radio command as the setpoint. The change in pack voltage represents a load to the PID loop and the ESC governor doesn't have to know or care that this is causing the motor speed to drop, it just always compares setpoint to actual speed and adjusts the current accordingly. It should do the same thing for loads due to flight maneuvers. I don't have an ESC or VBAR yet that will do this yet (just have a couple micro birds) so I am trying to understand how they work.

ReadyToCrash · 08-26-2012, 09:18 AM

hi,
i'm looking for advice on which sensor to buy to my v-bared electric heli.
thanks

02-25-2012, 06:10 PM	#1 (permalink)
tworst Registered Users Join Date: Feb 2011	governor question Does a governor actually control motor speed? That is, as the flight pack voltage decreases during flight, will the govenror try to maintain a constant relationship between radio commanded speed and actual head speed. So, at 90% commanded speed, it will maintain that speed regardless of the flight pack voltage. I am talking about an ESC or maybe an FBL like the VBAR. I know that the ESC/VBAR with a phase sensor can monitor the headspeed, but can it actually compensate for drop in voltage of the flight pack?

02-25-2012, 11:25 PM	#2 (permalink)
flerpie Registered Users Join Date: Jun 2009	Yes, they compensate for pack voltage. But they may not actually know what the pack voltage is. Doesn't need to. All it needs to know is what the target RPM is supposed to be (in settings) and what the headspeed actually is. Then it widens or narrows the motor driving pulses in an attempt to keep the headspeed where it should be. As pack voltage falls it will widen the pulse, effectively providing more current to the motor to keep the speed up. Perhaps some of the better governors actually do monitor pack voltage as part of the governing process...kontronic and YGE, maybe VBar. But the point is that knowing what the pack voltage actually is is not a strict requirement of the governing process. But probibly helps if the added sophistry is designed in. All just depends on the govenor design is all. __________________ HK Best Of Custom 450s & 500 Build Different!

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02-26-2012, 09:28 AM	#3 (permalink)
tworst Registered Users Thread Starter Join Date: Feb 2011	OK, thats kind of what I thought. I realize that actually knowing the pack voltage is not required although it could be usefull for gain compensation to get the same transient response. The motor speed is controlled by a PID feedback loop with the phase sensor (for VBAR) as the process variable and the radio command as the setpoint. The change in pack voltage represents a load to the PID loop and the ESC governor doesn't have to know or care that this is causing the motor speed to drop, it just always compares setpoint to actual speed and adjusts the current accordingly. It should do the same thing for loads due to flight maneuvers. I don't have an ESC or VBAR yet that will do this yet (just have a couple micro birds) so I am trying to understand how they work.

08-26-2012, 09:18 AM	#4 (permalink)
ReadyToCrash Registered Users Join Date: Feb 2010	hi, i'm looking for advice on which sensor to buy to my v-bared electric heli. thanks

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