HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Nov 24, 2011, 04:45 PM
Psalms 23:4
Goshen, IN, USA
Joined Nov 2010
267 Posts
Discussion
Rewound Motor Cuts Out

I recently rewound a motor, and it was running fine until it cut out midflight. I inspected all the wires, but it would cut out at about 2/3 throttle. I took the wires off and rewound them but it still quit at 2/3 throttle. so I replaced the wires with new ones. Same problem. It runs fine without a prop, and it's not the ESC, because I tried it with another motor, and it ran fine. I don't know what to check. Any help is appreciated!!
miniprinter96 is offline Find More Posts by miniprinter96
Reply With Quote
Sign up now
to remove ads between posts
Old Nov 24, 2011, 05:30 PM
Frequent Flyer
whitecrest's Avatar
Orleans, MA
Joined Feb 2007
2,095 Posts
It could be a timing problem. Programming the ESC for higher timing may get it running properly. Using a slightly smaller prop may also make the timing less critical.
whitecrest is offline Find More Posts by whitecrest
Reply With Quote
Old Nov 24, 2011, 05:33 PM
Psalms 23:4
Goshen, IN, USA
Joined Nov 2010
267 Posts
but I was using the same setup before with no problems.
miniprinter96 is offline Find More Posts by miniprinter96
Reply With Quote
Old Nov 24, 2011, 05:45 PM
Frequent Flyer
whitecrest's Avatar
Orleans, MA
Joined Feb 2007
2,095 Posts
If the timing is very critical, changing battery voltages due to normal aging might be enough to cause a problem. Even temperature and humidity might be enough to tip a delicate balance.
whitecrest is offline Find More Posts by whitecrest
Reply With Quote
Old Nov 24, 2011, 07:42 PM
homo ludens modellisticus
Ron van Sommeren's Avatar
The Netherlands, GE, Nijmegen
Joined Feb 2001
10,870 Posts
Better not measure current, or tell what battery/controller/prop was used. All useless info.
Ron van Sommeren is offline Find More Posts by Ron van Sommeren
Reply With Quote
Old Nov 24, 2011, 08:44 PM
Registered User
Joined Mar 2008
36 Posts
Did you rewind the motor with the same gauge wire and same number of winds? Also did you use the same wiring pattern, wye or delta? Both of these can affect prop size and timing needed. Is the motor just stopping completely or is it stuttering and making a chirping sound when it goes past 2/3 throttle?
slowjoe4821 is offline Find More Posts by slowjoe4821
Reply With Quote
Old Nov 24, 2011, 09:35 PM
Dude, I do fly all day long!
rcalldaylong's Avatar
San Jose, California
Joined Dec 2007
5,846 Posts
I've had rewound motors do this and the only thing that has helped is by using a cheap esc. I don't know why but i've just accepted that the more expensive esc's just won't work with some of those rewound motors.

The other thing to consider is your new wind probably is too high of kv and exceeds motor capability with the prop you are running. When it stops does it come to a screeching stop? Maybe post a vid. As the other poster above has said, try high timing on the ESC.
rcalldaylong is offline Find More Posts by rcalldaylong
Reply With Quote
Old Nov 25, 2011, 11:08 AM
Psalms 23:4
Goshen, IN, USA
Joined Nov 2010
267 Posts
My ESC doesn't have adjustable timing, so that's not an option.

For my first rewind, I used the same wind count as the original motor, and it ran fine for quite a while. Then, after it started cutting out, I rewound it using exactly the same wind, but it still cut out. So I rewound it using a thicker gauge, with WYE termination instead of Delta. Still didn't work. I'm completely lost.

Motor ~ http://www.hobbyking.com/hobbyking/s...idProduct=5427

ESC ~ http://www.hobbyking.com/hobbyking/s...idProduct=6457

Used an 8x4 and a 10x4 prop.

The original wind was 24 turns. The wind with thicker gauge wire had 12 turns. I don't know the wire gauges, as the wire was pulled off of old motors.
miniprinter96 is offline Find More Posts by miniprinter96
Reply With Quote
Old Nov 25, 2011, 02:14 PM
Dude, I do fly all day long!
rcalldaylong's Avatar
San Jose, California
Joined Dec 2007
5,846 Posts
Quote:
Originally Posted by miniprinter96 View Post
My ESC doesn't have adjustable timing, so that's not an option.

For my first rewind, I used the same wind count as the original motor, and it ran fine for quite a while. Then, after it started cutting out, I rewound it using exactly the same wind, but it still cut out. So I rewound it using a thicker gauge, with WYE termination instead of Delta. Still didn't work. I'm completely lost.

Motor ~ http://www.hobbyking.com/hobbyking/s...idProduct=5427

ESC ~ http://www.hobbyking.com/hobbyking/s...idProduct=6457

Used an 8x4 and a 10x4 prop.

The original wind was 24 turns. The wind with thicker gauge wire had 12 turns. I don't know the wire gauges, as the wire was pulled off of old motors.
You mean you are reusing old windings? That in itself can be an issue- old wire can already be full of shorts when you are pulling it. You should always use new wires.
rcalldaylong is offline Find More Posts by rcalldaylong
Reply With Quote
Old Nov 25, 2011, 02:29 PM
Psalms 23:4
Goshen, IN, USA
Joined Nov 2010
267 Posts
Quote:
Originally Posted by rcalldaylong View Post
You mean you are reusing old windings? That in itself can be an issue- old wire can already be full of shorts when you are pulling it. You should always use new wires.
No, I'm using wire from an old pencil sharpener, but I've used it before with no problems. It shouldn't have removed the coating though, because it was just wrapped around, not interwoven. And the thicker stuff is from a weedwacker, and I'm almost positive that it didn't have shorts. How do I check for shorts?
miniprinter96 is offline Find More Posts by miniprinter96
Reply With Quote
Old Nov 25, 2011, 02:39 PM
Dude, I do fly all day long!
rcalldaylong's Avatar
San Jose, California
Joined Dec 2007
5,846 Posts
Quote:
Originally Posted by miniprinter96 View Post
No, I'm using wire from an old pencil sharpener, but I've used it before with no problems. It shouldn't have removed the coating though, because it was just wrapped around, not interwoven. And the thicker stuff is from a weedwacker, and I'm almost positive that it didn't have shorts. How do I check for shorts?
if you have a wattmeter, check for continuity between your phase wires to the stator. If there is continuity, you have a short.

you can also use the drill test that Jack always suggest. Put your watt meter on AC and chuck the motor in the drill and run the drill then check between phases. The voltage should be very close.

I doubt it's a short though...from what you've said, it's more likely you've just over propped and your motor can't handle it...
rcalldaylong is offline Find More Posts by rcalldaylong
Reply With Quote
Old Nov 25, 2011, 08:55 PM
Psalms 23:4
Goshen, IN, USA
Joined Nov 2010
267 Posts
Quote:
Originally Posted by rcalldaylong View Post
I doubt it's a short though...from what you've said, it's more likely you've just over propped and your motor can't handle it...
But I've used the exact same setup before with no problems. I put more than an hour and a half on that motor.
miniprinter96 is offline Find More Posts by miniprinter96
Reply With Quote
Old Nov 25, 2011, 09:52 PM
Jack
USA, ME, Ellsworth
Joined May 2008
17,140 Posts
Let's see if I have this right.

1 - You rewound a motor with used wire...

2 - You reduced the turn count from 24 to 12 turns and used the same termination...

3 - And you're using the same size prop as was used on the motor when it was new and had twice as many windings...

Did you know that changing the turn count changes the Kv?

And that changing the Kv by more than a little means you have to use a different sized prop?

Jack
jackerbes is offline Find More Posts by jackerbes
Reply With Quote
Old Nov 25, 2011, 10:55 PM
Psalms 23:4
Goshen, IN, USA
Joined Nov 2010
267 Posts
Quote:
Originally Posted by jackerbes View Post
Let's see if I have this right.

1 - You rewound a motor with used wire...

2 - You reduced the turn count from 24 to 12 turns and used the same termination...

3 - And you're using the same size prop as was used on the motor when it was new and had twice as many windings...

Did you know that changing the turn count changes the Kv?

And that changing the Kv by more than a little means you have to use a different sized prop?

Jack
No, I had the same turn count on the first rewind (24), using Delta termination, and after that didn't work, I used a thicker gauge with 12 turns and WYE termination. I would have used 14, (the closest number to 24/1.7), but I couldn't fit more than 12 turns on the stator.
miniprinter96 is offline Find More Posts by miniprinter96
Reply With Quote
Old Nov 26, 2011, 09:37 AM
Jack
USA, ME, Ellsworth
Joined May 2008
17,140 Posts
OK, and changing the 24 turn wind from Delta to Wye would have lowered the Kv by a factor of about 0.58 or to about 754 or so if the original 1300 Kv spec was accurate.

Reducing the turn count from 24 to 12 would have doubled the Kv to 1504 or so with a Wye term. If you went back to Delta with the 12 turn wind it would raise the Kv by a factor of 1.73 and give you a 2602 Kv.

So now it appears that you have a 1504 Kv and that may be OK with the same prop if the wire sizes you used will handle the current draw. If you don't have any other way to do it, you'll be able to tell if the current draw is excessive by how quick the motor gets hot and how hot it gets. If you can get the motor running.

To check your wind there are some basic checks you can make using just a multimeter. One would be to check the resistance between the motor leads. Check every combination, if the leads are called 1, 2, and 3, check 1 to 2, 1 to 3, and then 2 to 3.

You should see a low but steady and unchanging resistance with the meter set to the 1 Ohm or Rx1 setting. It might be something like 0.4 Ohms or something like that, it may take it a second or two to settle down to a stable reading on each combination of pairs. It one is higher it might be a bad solder joint on the ESC connector, if all are higher or erratic there are probably shorted windings.

If it passes that test find a bare spot on the stator where you can touch one of the probes to it. I usually find a spot close to where the bearing tube comes out of the stator. You may have to scratch the stator with the probe tip to get through the coating on the stator

With one probe on the bare spot touch the other probe to the motor leads one at a time. You should not get any readings between the stator and the motor leads. If you see some readings or a flickering value, one of the windings is shorted to the stator.

At that point, if you passed all the checks, you have complete windings and no shorts. But you could still have a miswound stator, erratic turn counts, turns in the wrong direction, or even not on the right arms.

The spin test will tell you if you have the rest of it right. Here is a good thread on dry testing brushless motors:

http://www.wattflyer.com/forums/showthread.php?t=35216

That describes the spin test and how to do it. Testing step #34 in this thread also describes how to do a spin test:

http://www.rcgroups.com/forums/showthread.php?t=240993

Jack
jackerbes is offline Find More Posts by jackerbes
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Fox 0.25 glow RC cuts out at high RPN Texas Buzzard Engines 30 Oct 18, 2011 04:41 PM
Question Motor Cuts Out at WOT at Flight End BryanEW710 Batteries and Chargers 3 Oct 18, 2011 01:06 PM
Help! Motor cuts out even though voltage is ok DavidEFM Power Systems 5 Aug 22, 2011 12:48 AM
Discussion Motor Cuts Out Near Full Throttle theleetbeagle Electric Plane Talk 7 Jun 19, 2011 02:47 PM
Discussion Possible tx/rx issue (motor cuts out but other channels seem fine) mbreslin Radios 3 Apr 22, 2011 10:48 PM