MX400Pro flight recorder data & motor temps
01-11-2008, 11:16 PM
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MX400Pro flight recorder data & motor temps
Well, I've been thinking that my stock 6 pole motor in my
MX400 Pro was running kind of hot...
So, I installed a Medusa 'Oracle' flight data recorder today
and here are the readings I got.
This is with a 2200 mah lipo on board as well as an FMA
co-pilot, and of course the 'Oracle'.
Motor rpm....27000 rpm's....kind of high?
Rotor head rpm....2300...pretty good..12 tooth pinion.
Amps....12 and 1/2...seems low?
Motor temp..130+....seems low cause it burns my fingers
when I touch it...
It was also showing 133 watts..(not shown on graph)..that
seems low to me.
I will continue testing...
AB
MX400 Pro was running kind of hot...
So, I installed a Medusa 'Oracle' flight data recorder today
and here are the readings I got.
This is with a 2200 mah lipo on board as well as an FMA
co-pilot, and of course the 'Oracle'.
Motor rpm....27000 rpm's....kind of high?
Rotor head rpm....2300...pretty good..12 tooth pinion.
Amps....12 and 1/2...seems low?
Motor temp..130+....seems low cause it burns my fingers
when I touch it...
It was also showing 133 watts..(not shown on graph)..that
seems low to me.
I will continue testing...
AB
01-11-2008, 11:32 PM
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RE: MX400Pro flight recorder data
Bob- you got your recorder; cool
.Dunno, current and voltages don't look too far off what I had, though the Watts do seem a little high, not much. It doesn't look like you're loading the motor up too much, though; the 6p motor is 2580kV according to tower, so 10.7V you'd be looking for 27000 RPM and you're spot on.
01-11-2008, 11:45 PM
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RE: MX400Pro flight recorder data
Osterizer:
Yep, got the recorder....its really cool..I even put it in my Slow Stick.
You think the Watt's are high? I was thinking it should be more like
200+ Watts...
But, the Amps are low also, so maybe 133 watts is close to right
The motor itself appears to be running wide open...no reserve power
there..
I'll keep playing with it and see if those are good honest figures....I'm
glad to see the motor temp is not as bad as I thought. Now I'll fly the
heli a little more often.
Take care,
AB
Yep, got the recorder....its really cool..I even put it in my Slow Stick.
You think the Watt's are high? I was thinking it should be more like
200+ Watts...
But, the Amps are low also, so maybe 133 watts is close to right
The motor itself appears to be running wide open...no reserve power
there..
I'll keep playing with it and see if those are good honest figures....I'm
glad to see the motor temp is not as bad as I thought. Now I'll fly the
heli a little more often.
Take care,
AB
01-11-2008, 11:53 PM
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RE: MX400Pro flight recorder data
You too, man. Yes, mine is about 120/130W hovering, so we're getting within sampling error of each other. I'd watch the temp, of course; I keep one of the little Graupner iR thermometers in my pocket and check the motor and pack temps after almost every flight. Might be a little paranoid on my part, but I'm ok with that .
.
01-13-2008, 05:37 PM
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RE: MX400Pro flight recorder data
Osterizer...
Well, I'm still dazzled by how low the Watt readings are. I know that if
I tried flying it with a 135 Watt motor it would not fly. Very strange to
me.
I have one of the IR thermometers. Guess I better find it and see what
kind of readings I get.
I'm gonna try the 'Oracle' in my son's MX450XL next. It's an excellent
flyer and the motor and battery's only get barely warm. But, I want
to check it anyway just for the records.
Keep you Watts up..
AB
Well, I'm still dazzled by how low the Watt readings are. I know that if
I tried flying it with a 135 Watt motor it would not fly. Very strange to
me.
I have one of the IR thermometers. Guess I better find it and see what
kind of readings I get.
I'm gonna try the 'Oracle' in my son's MX450XL next. It's an excellent
flyer and the motor and battery's only get barely warm. But, I want
to check it anyway just for the records.
Keep you Watts up..
AB
01-13-2008, 11:48 PM
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RE: MX400Pro flight recorder data
If you start to fly hard 3D and you hear the motor start to bog down, then it will be pulling some large amps. At just a hover there's not a lot of load on the motor.
01-14-2008, 10:35 PM
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RE: MX400Pro flight recorder data
PilotLight...
I'm sure you're right. I guess I had better fly it around a little bit
and let my son wring it out a little and see what readings I get.
No inverted stuff though.... I'm too much of a purist for that. When
I see Care-Flight hovering upside down over the hospital then maybe
we'll try it.
AB
I'm sure you're right. I guess I had better fly it around a little bit
and let my son wring it out a little and see what readings I get.
No inverted stuff though.... I'm too much of a purist for that. When
I see Care-Flight hovering upside down over the hospital then maybe
we'll try it.
AB
01-15-2008, 04:07 PM
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RE: MX400Pro flight recorder data
AB,
One thing I learned about these electric motors is they try to turn the same RPM for a given voltage. They just increase amperage as the load increases. If you spin a motor without any load it draws almost no amps.
One thing I learned about these electric motors is they try to turn the same RPM for a given voltage. They just increase amperage as the load increases. If you spin a motor without any load it draws almost no amps.
01-15-2008, 05:36 PM
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RE: MX400Pro flight recorder data
Right - that's the way a synchronous motor works - the poles are electrically moved around the core at a certain rate (now, this is backwards on an outrunner!), and the core tries to stay in step.That's why you cannot just drop the voltage to change RPM - what happens is as you drop the voltage, the poles do not have enough magnetic pull to keep the core synchronous, and it stats slipping behind - then you get a heat build up.
This is brushless, BTW - standard motors vary the RPM via voltage.
This is brushless, BTW - standard motors vary the RPM via voltage.
01-15-2008, 09:39 PM
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RE: MX400Pro flight recorder data
Well then, when you are running at 1/2 throttle you are
lowering the amps but not the voltage???
I wonder what voltage each leg of a brushless inrunner 'see's' ?
AB[
]
lowering the amps but not the voltage???
I wonder what voltage each leg of a brushless inrunner 'see's' ?
AB[
]
01-16-2008, 09:51 AM
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RE: MX400Pro flight recorder data
No, at half throttle, the synchronous signal sent to the motor is "spinning" at half speed. The full amperage is available to the motor throughout the throttle range. That's why brushless motors are so powerful as they have almost full power throughout their speed range.
