Notices
Electric General Discussion General Discussion forum about rc electric related aircraft, accessories, flight, tips, etc.

Motor trouble

Old 11-30-2011, 02:08 PM
  #1  
ejc34710
Senior Member
Thread Starter
 
Join Date: Sep 2008
Location: brookville , OH
Posts: 490
Likes: 0
Received 0 Likes on 0 Posts
Default Motor trouble

Heya fellas, hoping for a little help here. I have a 24inch flying wing (speedwing) powered by an E-flite pro 25 amp ESC, SFM 20x40mm 4700kv inrunner, GWS 4x4 prop, with a Thunder Power 850mah 3s 45c. I think i may have fried the motor but not sure. It quit working mid-flight last time i flew it and it wouldn't spin after that, just kinda pulsate around. I smacked the motor shaft lightly with a screwdriver handle and it started working again. Went out to fly it, and it did the same thing. I can still hit the shaft to get it working but it quits shortly after again, usually when i give it over 50% throttle. I know i was pulling too many amps (around 31ish i think, motor rated at 25) so i'm pretty sure i fried the motor but wanted someones advice as to whether or not they know for sure. Already have an E-flite 20x40mm 4200kv inrunner ordered at my LHS (which will get the amps down to around 25) but just wanted to make sure it was the motor, not the ESC. You guys ever hear of anything like this before? Thanks for any help.
Old 11-30-2011, 03:29 PM
  #2  
cubaneight
Senior Member
 
Join Date: Apr 2004
Location: Colchester, UNITED KINGDOM
Posts: 114
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Motor trouble

One or both motor bearings jamming perhaps? Sounds odd that the motor runs ok for a while after you tap the shaft. Are you able to turn the armature by hand when the problem occurs? If you can - probably shorted windings.

Hope this helps

C8
Old 11-30-2011, 07:12 PM
  #3  
ejc34710
Senior Member
Thread Starter
 
Join Date: Sep 2008
Location: brookville , OH
Posts: 490
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Motor trouble

Yea, after the motor starts acting up i can still spin the shaft by hand. It is as if there wasn't anything wrong. But it kinda flips the prop back and forth sporatic-like when it's acting up and i give it juice. The ESC gets warm/hot too.
Old 11-30-2011, 07:14 PM
  #4  
ejc34710
Senior Member
Thread Starter
 
Join Date: Sep 2008
Location: brookville , OH
Posts: 490
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Motor trouble

I might add that the motor and ESC are brand new. They have had less than 3 flights through them. Actually, they worked fine up until the begining of the 3rd flight, when the motor quit and showed the symptoms listed above.
Old 12-01-2011, 06:51 AM
  #5  
Glacier Girl
My Feedback: (4)
 
Glacier Girl's Avatar
 
Join Date: Jul 2004
Location: Lakeland, FL
Posts: 7,906
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Motor trouble

The cogging back and forth is a sign of an open winding, could be something as simple as a cold solder joint, or a broken winding inside the motor. The motor when it cogs like that is showing that one of the legs is not working and the motor can't decide what to do, creating a dead short, and why the esc is getting hot. You'll eventually let the magic smoke out of the esc and motor if you keep running it like that.

Is the set up letting good airflow to the motor? I would think if the motor is rated for 25 amps and your set up pulling 31, you should have been OK with good airflow and throttle control.
Check all your solder joints and the 3 legs on the motor for continuity.
I used to pull 50+ amps out of Mega's, rated at 23 amps in my Strykers and NEVER had an electrical failure. But on those the motor sat out in the airflow.
Old 12-01-2011, 08:55 AM
  #6  
ejc34710
Senior Member
Thread Starter
 
Join Date: Sep 2008
Location: brookville , OH
Posts: 490
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Motor trouble

Yes, the motor sits completly out in the open. The ESC gets lots of airflow as well. Guess i bought a junk motor. 60.00 bucks for 2.5 flights, last time i ever buy a "Super Flying Models" product again. Thanks for the help though.

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 Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.