DIY DC Electric Motor

DIY Electric Motor

When I was 10 years old, I built these kind of electric motors by following the instructions in the book "Pieniä Sähkömoottoreita, Poikien askartelukirja" (Small Electric Motors, Boys' Craft Book). I decided to rebuild one during the Christmas holidays. There is hardly any practical use for this motor, but it is a nice and fun crafting. You can build a similar electric motor by following the pictures and by using your imagination. I am sure that you will enjoy this handcraft.

Rotor is made of two 18mm x 0.25mm soft iron plate strips. The axle is 2mm brass rod.	Rotor winding. 2 x 40 turns 0.4mm magnet wire on two layers each side. Add tape between the layers.	Totally 160 turns. You may wind more turns for better efficiency. Same winding direction for both sections.
Rotor plates initially folded	Rotor plates cut and shaped	Balance rotor by cutting edges if needed
Drilled plastic rod and folded plates for commutator	Commutator plates (red) clearance toward poles	Commutator plates 'sewn' and the wires soldered
Stator is using the same soft iron plate as rotor	Stator winding is similar to rotor. 2 x 40 turns layers on both side. Continuous winding direction.	Stator strips initially folded
Stator installed	End parts with bearing holes	Rotor pre-installed
End parts folded too keep the axle in place	Spring-like thin plates should be used for brushes	Brushes installed and preliminary test run performed

Notes
1. The motor efficiency is not very good. It runs with 3V-5V DC supply at abt 1A current. I suggest more turns to the windings.
2. I suggest to use a bit thicker soft iron plate eg iron roof sheet for rotor and stator. It must be ferromagnetic iron. Aluminum, copper, brass etc will not work.
3. I used the same tinned iron plate for commutator. Much better for commutator is eg thin brass or copper sheet.
4. The cu magnet wire size is not critical, you can use enamel insulated cu wire from 0.2mm to 0.5mm.

Conclusion
Doing things with your hands is much better for your mental health than browsing the internet. Using imagination makes you feel even better. I recommend handcraft!

Update 2025-01-07 OH7SV

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