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Power Systems Talk about motors, ESC speed controllers, gear drives, propellers, power system simulators and all power system related topics

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Old 09-17-2008, 08:57 PM   #26
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I think the answer is very simple - your tiny 900mAh pack can't supply the amps the motor wants, voltage under load drops to <3v/cell, and you hit LVC - shuts down motor but servos still work fine. I have no clue what you motor is actually drawing, but perhaps 20A+... no 900mAh pack (even a 20C pack) will survive that for long. You need to measure amp draw at WOT and size your pack appropriately... I'd say 4s 2100 would do it.


Another thought - is you ESC really 4s compatible... I know it says 18v, but is anything more than 3s only possible with the internal BEC disabled?
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Old 09-18-2008, 02:11 PM   #27
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blowing regulators:
this isnt completely relevant to any questions asked so far, but it might be interesting anyway to people who wonders if their motor has been blown.

when your motor "blows", what usually happends is that you burn off the insulation on the coils, and hence your motor is a big short circuit.
this is no good for regulators, and your regulator WILL be blown, if not shut down immediately.
it will usually still beep as usual (not motor beep though, but those with piezo speaker) and bec power WILL work as usual even after blown.
this is because the main current only passes through the final gate transistors, and the main electronics is hence not affected by current draw.
this is good news for those with blown regulators, it means that there is every chance that the "brain" (microcontroller) with auxilary electronics is all fine, and that if you change your final gate switching transistors, yout regulator will be good as new. you can even change them for higher rating ones, and make your 20A into a 200A regulator. or, your blown regulator can still serve as a BEC together with another regulator who has no bec, and that wont be any problem. i bought a 120A without bec, and if it wasnt because i had a homemade bec already, i would probably use my blown 80A as BEC together with the 120 A.
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Old 10-10-2008, 12:10 AM   #28
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Default blown ESC

Turns out it was my esc all along, crappy 40 A ESC died while only using 14.8v 900mAh 15C lipo, what a piece of junk! anyway thanks for the help. Hopefully my new 80A ESC can handle the fury of my 900mAh batteries. lol
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Old 02-16-2010, 07:33 AM   #29
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Default the beep....

Hi all!
[email protected], so I just thought I should say Hi!


The beep should indicate that the esc is alive.... I've had beeps from the esc with a broken motor(1 phase missing) many times, as well as with a BBQ'd engine. But I've never had it with a broken esc.
However! I have always experienced that even with a toasted or 1 phase missing motor, it has always had some respons to throttle... often by wobbling back and forth or something like that. I would in your case also raise a warning for the receiver... If you get a beep but no throttle reaction what so ever, there might be a problem with your radio equipm. likely the receiv.

And one thing more ... after reading the discussion about different wiring diagrams in motors.... do you really say "star" or "triangle" configuration ???
Never heard that before.... I've always been told "wye" or "delta" configuration.... but then again I'm from sweden so WATT do I know...

Edit! Baaad reader.... :-) missed the second page and didn't see that your problem was solved... so it was the esc.... and you still got beeps from it....

Stay safe!
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Old 02-16-2010, 06:16 PM   #30
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Originally Posted by oso View Post

And one thing more ... after reading the discussion about different wiring diagrams in motors.... do you really say "star" or "triangle" configuration ???
Never heard that before.... I've always been told "wye" or "delta" configuration.... but then again I'm from sweden so WATT do I know...

Stay safe!
I taught service classes for our customers on three phase power circuit breakers for some 40 years. (All the way from controls that used vacuum tubes, to the present controls that are microprocessor controlled)

These guys who deal with high voltage three phase equipment use "Wye" or "Delta" for describing connections to the various three phase equipment that they use.
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Old 06-05-2014, 01:11 AM   #31
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Default Just bringing back an old thread

This thread was put together several years ago for a quick check of a brushless motor. Time for an update

One of my club members gave me an E-Flite power 32 motor with obviously fried windings. Note that only ONE winding is fried, the rest of the windings look OK.

Using the winding resistance check, the motors three windings measure as follows:
Blue - Red 0.0164 Ohms
Blue - Black 0.0205 Ohms
Red - Black 0.0209 Ohms

Resistance measured with this procedure
http://www.wattflyer.com/forums/showthread.php?t=50740

Next, the motor was spun up to 1000 RPM with a battery operated drill, with all three motor leads isolated from each other. There was a LOT of drag. There should be little or no drag.

After several seconds, that fried winding was checked, it was HOT. What happened is, the fried winding has shorted turns. So when the motor was spun up, those shorted turns had a lot of current generated through them, winding up getting hot.

Last, the voltage was measured on each winding when the motor was spun up at 400 RPM. The three voltages measured 0.292, 0.324 and 0.218 Volts AC.

Since none of the other windings were overheated, my suspicion is that the winding had an insulation defect, that finally shorted out.


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Old 11-17-2015, 02:57 PM   #32
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This is a great thread. I have a seaplane that took a dunking and the motor fails now. I will use the tests from post #1 to verify the motor condition.

Glen
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