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

"Dry Testing" brushless motors (Update Sept 10 2008)

Old 09-17-2008, 09:57 PM
  #26  
Dr Kiwi
Super Contributor
 
Join Date: Aug 2005
Posts: 1,726
Default

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?
Dr Kiwi is offline  
Old 09-18-2008, 03:11 PM
  #27  
Moxus
Gremlin
 
Join Date: Jun 2008
Posts: 641
Default

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.
Moxus is offline  
Old 10-10-2008, 01:10 AM
  #28  
stedt001
New Member
 
Join Date: Sep 2008
Posts: 2
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
stedt001 is offline  
Old 02-16-2010, 08:33 AM
  #29  
oso
New Member
 
Join Date: Feb 2010
Posts: 1
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!

Last edited by oso; 02-16-2010 at 08:37 AM. Reason: oops...
oso is offline  
Old 02-16-2010, 07:16 PM
  #30  
kyleservicetech
Super Contributor
Thread Starter
 
kyleservicetech's Avatar
 
Join Date: Apr 2008
Location: Wisconsin, USA
Posts: 8,952
Default

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.
kyleservicetech is offline  
Old 06-05-2014, 02:11 AM
  #31  
kyleservicetech
Super Contributor
Thread Starter
 
kyleservicetech's Avatar
 
Join Date: Apr 2008
Location: Wisconsin, USA
Posts: 8,952
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.
Attached Thumbnails Click image for larger version

Name:	Fried Winding.jpg
Views:	286
Size:	138.3 KB
ID:	175907  
kyleservicetech is offline  
Old 11-17-2015, 03:57 PM
  #32  
ggcrandall1
8000' and going down fast
 
ggcrandall1's Avatar
 
Join Date: Nov 2007
Location: Marietta, Ga
Posts: 14
Default

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
ggcrandall1 is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Sky Sharkster
Vintage and old timer models
4
05-10-2008 02:14 AM
admin
General Electric Discussions
2
02-26-2007 10:42 PM
springer
Events, Shows and Fun Fly's - Electric Airplanes
7
08-20-2006 07:23 PM

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Quick Reply: "Dry Testing" brushless motors (Update Sept 10 2008)


Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.

Page generated in 0.09369 seconds with 12 queries