Unipolar stepper motor rewinding to fix short circuit

This video shows the process of fixing a PTZ camera, that did not move up and down. The were two issues - short circuit in motor's winding and damaged ULN2003 driver IC.
The motor was fixed by disassembling it and rewinding the winding.
0:15 Some theory about how stepper motors work, difference between unipolar and bipolar motors, number of wires that come out.
5:53 Determining the type of motor in the camera, measuring winding resistance to find out the pinout.
8:23 Opening the motor
10:19 Measuring wire diameter, calculating the necessary wire length.
11:59 Sourcing wire from relays, electromagnets...
13:39 Winding process
16:22 Finding the mistake in winding connection and fixing that
19:57 Testing ULN2003 driver with an LED
21:16 Soldering a new driver chip
Notes:
• To make the new winding with exactly the same characteristics as the old one we should rather count number of turns in the old winding and make the same number of turns in the new one (and, obviously, use the same diameter wire). But we assume that if wire length is the same, the number of turns will be more or less the same.
• The calculation of wire length shows 0.15mm wire diameter which was wrong. The actual diameter was about 0.12mm (0.14mm with enamel).
• It's nearly impossible to wind the wire as accurate and dense as it's made on factory so it could be hard to fit all the wire, but it still works with shorter wire if the difference is not too high.

[@JzoneMD]

Very nice video, well done.👍👍👍😊

[@JzoneMD]

Very nice video, well done..👍👍👍

[@stickyfox]

Just as an FYI, there are standard diameter charts for magnet wire, bare or with various enamel coatings too!

[@ColeGove]

Impressive, thank you for sharing

[@genaro8706]

This was really helpfull!!

[@shahidfarooq2461]

If resistance of both coils of unipolar motor are same and driver is also working but motor does not run than where the problem will be? Does rotor Magnets get weak?

[@shahidfarooq2461]

Can you tell me how to convert bipolar step motor to unipolar step motor?

[@TriangleBox]

how to rewind nema 17??and how to remove inside plastic core??

[@FilippSudanov]

I had no experience that would involve opening a nema17 motor, so can not comment much.

[@danm3188]

Heh... whole lot of work for a $3 part (if you can find it). Looking at doing something similar for a 30 year old turntable stepper motor.

[@GeorgGeor]

На твоей схеме одна обмотка замкнута (кружок с точкой и одним проводком). Скажи пожалуйста, какая польза от неё, что она делает? Или она служит, попеременно, как бы обкладкой конденсатора, то есть вносит какую-то ёмкость?..
In your circuit, one winding is closed (a circle with a point and one wiring). Please tell me what is the use of her, what is she doing? Or does it serve, alternately, as if a lining of a capacitor, that is, it introduces some capacity? ..
Речь о плоской катушке, которую Вы наматывали.
It's about the flat reel that you wound.
Какая из двух схем правильная? Which of the two schemes is correct?
1) czcams.com/video/Q7Mo2FejyIo/video.html
2) czcams.com/video/Q7Mo2FejyIo/video.html

[@FilippSudanov]

На 17:37 примерно? Это было ошибочное подключение, когда я неправильно соединил выводы катушек.
If you mean around 17:37 - that was wrong connection of winding wires, I fixed it later.