Motor Stuttering / Cogging

[Keith Newman]

hi just got a cheap hextronic brushless motor off of Hobbyking.

It is having a issue, that i believe you call cogging or stuttering.

I have checked the three cables going into the brushless motor with a DVM on continuity setting and only 2 out of 3 wires give continuity (is that wrong)?

The motor will not start up, my esc has been checked with other motors and working fine.

All that happens is, either nothing, or a little bit of it kind of vibrating back and forth.

Hobbyking are replacing the motor. I was just curious what it would be.

Thank you

I have checked all my connections and they appear fine.

Just curious about what i found with the DVM on continuity as other brushless motors i checked had continuity on all three wires.

Thank you

[Peter Beeney]

Keith,

If you are checking the continuity simply between the 3 wires into the motor it very much sounds as if there is some sort of internal break. It’s most likely wound in star, so it may well be where all three ends are terminated together. If so, then the replacement is really the only solution.

Star or delta configuration, there will always be permanent continuity between all three wires.

Good Luck.

PB

[Piers Bowlan]

You have checked your ESC with other motors but have you tried another ESC with your stuttering motor? Perhaps your ESC does not have the correct timing for the motor in question? Which motor /ESC are you using? Like you say, it may be just a case of a damaged winding if you don't have continuity.

[Cuban8]

Open circuit winding so a bin job or exchange.

[WolstonFlyer]

Or take it apart and see if you can spot the problem?

[Gordon Skene]

try a smaller prop sometimes they do this if the prop is to big especially with inrunners

[Bob Cotsford]

Before you bin it, try re-soldering the connectors.

[Former Member]

[This posting has been removed]

[Steve Hargreaves - Moderator]

As Bob sez it could just be a dodgy connector joint.....the enamelled wire is not easy to clean & solder & a poor joint here will give the symptoms you describe.

Resolder the connectors before condemning the motor....

On the other hand, if its a new motor, then straight back to the supplier it goes....

[Keith Newman]

Found the problem.

on very close inspection, the three wires that go into the motor bell. Next to the windings for the Stator, 2 had snapped / broken on the windings to the stator.

Tried to solder it, but it was very hard for it to take. Did finally manage to bodge it together and check with the DVM for continuity and it worked.

Anyhow. Cannot solder it. So have stripped the motor. Took all the windings off, So now I have on my bench 1 very long piece of copper wire (i am guessing this it coated in something?) and 4 smaller pieces of copper wire which if were not broken would equal a total of 3 long pieces.

Seeing as I am now in a position to try winding my first ever motor.

Can I have some guidance on how to try this.

I presume I would need to order some more wire as may not be long enough what I have ?

Thanks all

[PatMc]

Some advice on how to wind B/L motors contained within this and this link. Between the pair you should be able to extract what you need.

BTW I'd go with a "delta" connection.

[Andy G.]

If nothing else, SAVE the magnets for hatch, canopy etc fixing, nothing's ever a total write off!

[Engine Doctor]

A tip while your re winding your motor is to switch off you phone , ! Lock yourself in you den and put a"Do not disturb" notice on the door . when you get near to finishing the windings and your phone rings or your wife calls it very easy to forget how many winds you have done . 1 wind different will cause the motor to malfunction. The first motor I re wound worked brilliantly so thought it was a breeze. The second time I tried it I couldn't get it to work and motor kept stuttering even after two or three attempts. I don't bother now as motors are so cheap. It's not worth the bother.good luck and let us know how you get on.

[Geoff S]

Posted by Keith Newman on 23/04/2016 15:40:07:

Anyhow. Cannot solder it. So have stripped the motor. Took all the windings off, So now I have on my bench 1 very long piece of copper wire (i am guessing this it coated in something?) and 4 smaller pieces of copper wire which if were not broken would equal a total of 3 long pieces.

Yes the wire will be enamelled copper wire which has been used for winding coils ever since they stopped insulating it with either silk or cotton - long before I wound any as a schoolboy in the early 50s.

One of my first jobs was winding coils for radio and TV sets in smallish numbers for service replacements at Murphy Radio. We used to clean off the enamel by burning it in a clean flame and dipping the still hot wire in a small bath of methylated spirit. It came out bright copper clean and easy to solder. Another way is to to fold a small piece of emery paper and stroke the wire gently. The first method is best.

Not sure it's worth rewinding the motor except as an exercise just to see if you can. Brushless motors are very inexpensive now unless you go into exotic territory, like (say) Hacker.

Geoff