I have these drone motors. The 2 elect wires go to a top insulated plate and there is no visible connection to the motor winding from there, so not sure how they work? Any ideas welcome
https://www.aliexpress.com/item/329...o.order_list.order_list_main.4.21ef1802LukWtI

 

They look like normal PMDC motors to me. The wires would be connected to brushes inside .

 

The tiny brushes on those cheap motors do not last long. Some motors like that needed replacement after only ten 10 minutes flights. When the motor fails then the drone crashes.
All of my similar but brushless motors have lasted for hundreds or thousands of flights and still work like new.

 

Thanks. The chip that controls these motors is marked:
SO292
9926A
Not sure what chip this is?

 

9926A is a MOSFET Transistor used for
PWM Switching of the Permanent-Magnet, Brushed-Motor.

Those Motors are cheap garbage for "throw-away" Toys.
.
.
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A closer examination should reveal a commutator, verifying that they are not brushless motors. The magnets might still be useful somehow, though.

 

That's the problem - opened motor, no sign of brushes or comm, magnet quite strong.

 

Then the manufacturer did not even bother to test the motors. No quality control when things are built cheeeeaply over there.

 

These are coreless brushed motors. Although you didn't recognise them, they DO have brushes and a commutator. They are certainly inexpensive (<$4.00) but are quite well made. They will not last very long when pushed to the limit of their performance, as in small quadcopters.

 

I look at the picture in the ad and I see two wires. NEXT QUESTION IS WHERE DOES THE ts SEE THAT CHIP THAT CONTROLS THE MOTORS??
Did the TS ever see the motors work?? Does the TS have a failed drone? Suddenly I see that there is a lot more to the story than we are told.The motors in the picture have gears, not props.
I smell a bad smellhere.

These are coreless brushed motors. Although you didn't recognise them, they DO have brushes and a commutator. They are certainly inexpensive (<$4.00) but are quite well made. They will not last very long when pushed to the limit of their performance, as in small quadcopters.

Where did KW get that information??? certainly not from the link posted.

 

Where did KW get that information??? certainly not from the link posted.

I got that information from the link posted. If you look at the illustration, you will see that the motor is 8.5mm in diameter and 20mm long. That is the way the cheap quadcopter motors are classified, plus the direction of rotation. Therefore it is a 8520 (A orB) coreless 3.7VDC drone motor. The part No. 8520 is at the top of the picture. See the following link:

https://www.aliexpress.com/item/1005002579340097.html?spm=a2g0o.productlist.main.7.631fzhnCzhnCwn&algo_pvid=c67284ac-fa61-4e5f-8a10-b5acf8ecae58&algo_exp_id=c67284ac-fa61-4e5f-8a10-b5acf8ecae58-3&pdp_npi=3@dis!CAD!0.87!0.67!!!!!@211beca116852097628754554d07ea!12000021238921141!sea!CA!0&curPageLogUid=nDoIVvV8bxk6

 

Cheap coreless motors spin at a high RPM and have very weak thrust. The thrust is boosted with gears.
Frequently the tiny brushes burn-up like a fuse if something gets caught in the propeller when it is flying.

 

OK, and from them having only two leads we know they are not BLDC motors.

 

So I replaced the motor and now the motor runs but one of the other motors runs for 5 secs and then stops. Any ideas why?

 

I am guessing that the replacement motor draws more current and that the driver is overheating. Notall motors are rated the same.

 

So I replaced the motor and now the motor runs but one of the other motors runs for 5 secs and then stops. Any ideas why?

There can be quite a few reasons why the motor quits after 5 seconds:
The motor could have a short in the rotor or commutator, causing it to overload the driver chip. Does the corresponding MOS FET get warm?
There may be fluff or a hair wrapped around the motor shaft, interfering with the bearing surface, again causing an overload.
The brushes could be burned and arcing.
The MOS FET may have become intermittent form repeated overloads.
Does a different motor work correctly when it is substituted for the faulty one?
If one of those motors is damaged, there is very little you can do to repair it.