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Old Dec 06, 2013, 09:29 PM
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United States, WA, Puyallup
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Question
Het 4w sagging

just picked up a used HET 4w and ran it for the 1st time , hooked up a 3S 2200 @ around 11.4 V and a 55A esc 6X4 APC .....throttled up and the motor wound up then started sagging around max throttle, could that be the timing or is their something else goin on? I don't know where the timing is right now
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Old Dec 07, 2013, 07:33 AM
Jack
USA, ME, Ellsworth
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What is the Kv on that motor? If the Kv is high enough it may be that the permutation rate needed to run the motor is too high for the ESC to handle.

If you put the ESC on it's highest timing setting it may change things and too.

Jack
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Old Dec 07, 2013, 03:52 PM
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haven't hada chance to check the KV but b4 going to all that work hooked up a hot 4S and that took care of the problem so think were good
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Old Dec 08, 2013, 08:48 PM
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Unglued??
Best check it over .. with care.
Regarded by some as a Perf motor... It nonetheless is 'Fabrique en Chine' with IMO sketchy QC issues .
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Old Dec 08, 2013, 08:48 PM
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Until we know exactly which HET 4W you have we are guessing!!!!
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Old Dec 09, 2013, 12:51 PM
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Originally Posted by Bare View Post
Unglued??
Best check it over .. with care.
Regarded by some as a Perf motor... It nonetheless is 'Fabrique en Chine' with IMO sketchy QC issues .
unglued.........as in "it came to life
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Old Dec 09, 2013, 02:56 PM
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Originally Posted by Dr Kiwi View Post
Until we know exactly which HET 4W you have we are guessing!!!!
For Sport aerobatics up to 1300 grams. The 4W is suitable for HET EDF unit 6904 or WeMoTec 480 mini fan.
◾Diameter: 28 mm
◾Length: 38 mm
◾Shaft Dia.: 3.17 mm
◾Li-Po:3-4S
◾Weight: 78 grams
◾No load current(lo): 1.94
◾Internal resistance: 0.013
◾KV: 2250
◾No. of poles: 6
◾Max Current: 30 A
◾Max efficiency: 88%
◾Power Nominal: 450 Watts
◾Recommended Props: APC E 6.5 X 4 or 7 X 4 (3s Lipo Only


it sez 3S for above props but think if I prop down it might be ok on a 4S on a zagi type wing
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Old Dec 09, 2013, 03:33 PM
Jack
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With 6 poles (magnets) it must be a 9 arm stator and wound ABCABCABC, you can't have 6 poles on a 12N motor. And at the 450W nominal they say it is good for it would be at 7.6W per gram. I wonder if it is that good or not?

Jack
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Old Dec 09, 2013, 07:39 PM
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If you are going to adhere to the 30A max, then even 6x4 on 3s might take you close to that.. (78g @ 3W/g is only 234W max.).........for 4s you will definitely need to run a tiny prop
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Old Dec 10, 2013, 09:54 AM
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Is it possible the 3S battery you are using doesn't have enough discharge capability for this motor?

I had a similar problem with a completely different motor/esc combo. A change to a lipo with a higher C rating cured it.

What is the C rating your 3S, and how many amps was the motor pulling?
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Old Dec 10, 2013, 03:20 PM
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Originally Posted by FormulaZR View Post
Is it possible the 3S battery you are using doesn't have enough discharge capability for this motor?

I had a similar problem with a completely different motor/esc combo. A change to a lipo with a higher C rating cured it.

What is the C rating your 3S, and how many amps was the motor pulling?
it was just a cheapo low C rating lipo so was prolly most of the problem.I have not had time to get any readings. what I need to do is charge up a decent high C 3S bat then do some testing, the 4S will be a bit scary to get any readings
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Old Dec 10, 2013, 03:47 PM
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I would try that. It certainly cleared up my problem, anyway.

Did it make full rpm for a second, and then back off...or did it never hit full rpm? If it hit full, then backed off - that does sound like a battery problem.

Did it surge at full throttle?
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Old Dec 10, 2013, 04:40 PM
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Originally Posted by FormulaZR View Post
I would try that. It certainly cleared up my problem, anyway.

Did it make full rpm for a second, and then back off...or did it never hit full rpm? If it hit full, then backed off - that does sound like a battery problem.

Did it surge at full throttle?
haven't got to it yet
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Old Dec 10, 2013, 06:29 PM
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haven't got to it yet
I meant with the 3s you tried first...
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Old Dec 10, 2013, 09:44 PM
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Originally Posted by FormulaZR View Post
I meant with the 3s you tried first...
yes
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