0
\$\begingroup\$

I decided to try and create a 4-pole 2-phase induction motor for learning purposes. After taking a class in the principles of electromechanical energy conversion (a few years ago) I was dissatisfied in not being able to build and test these circuits myself since there is a lot more material science and mechanical engineering involved compared to breadboarding analog/digital electronics. I started by making a squirrel cage rotor, and used an old sink drain as the stator, and used a 12 µF cap for a ceiling fan to create a 90 phase shift for the auxiliary winding, and developing the rotating magnetic field.

I did 800 turns of 28 AWG wire on the auxiliary winding, and 400 turns of 22 AWG on the primary winding, unfortunately, it doesn’t work too well with the squirrel cage rotor due to my poor drilling of the stainless steel stator, the poles are not very straight and the rotor will get stuck on them, though I ended up getting rotation with a small aluminum lid. The torque in the motor seems to be a lot less than what I was expecting, though.

The amperage it draws is around 1.5 amps, my goal was to keep the flux path closed and minimize air gaps, so I also wrapped it in galvanized steel wire and filled the rotor with iron nails, which is made out of aluminum wire curved to even out the torque. I’m sure the eddy current loss at this point is very significant since I am not doing anything to reduce the current in the ferromagnetic material, and maybe leakage inductance and hysteresis could be causing issues...

I’m planning on trying a larger cap, and maybe getting rid of the sink for the stator, though I’m not sure what my best bet would be for keeping a closed flux path with minimal air gaps, without resorting to silicon steel sheets. As even a little bit of air in the flux path can significantly increase the reluctance thus reducing the inductance. I also should mention I haven’t looked into the problems hysteresis could cause for me either, but I assumed with soft iron it shouldn’t affect things too much, though the galvanized steel could be a problem. Any suggestions or insight would be greatly appreciated.

Motor with aluminum lid rotor

\$\endgroup\$
4
  • 1
    \$\begingroup\$ Stainless steel comes in austenitic configuration as well as martensitic: did you check your specimen is ferromagnetic? \$\endgroup\$ Commented Jul 20, 2024 at 5:19
  • 1
    \$\begingroup\$ (Answers may be more to your point when you state what your point is.) \$\endgroup\$ Commented Jul 20, 2024 at 5:22
  • \$\begingroup\$ In particular, the most common stainless steels (304 aka 18-8 and 316) are not ferromagnetic. The ferromagnetic stainless steels are the 400 series, which tend to be more specialized and more expensive. \$\endgroup\$ Commented Jul 20, 2024 at 19:13
  • \$\begingroup\$ I ended up using galvanized steel for the washers and the wire surrounding the stator, the cores are soft iron, and I made the rotor out of aluminum wire and iron nails. The stator and the previous hardware I used actually ended up being austenitic and not very high permeability, but the galvanized steel ended up having better permeability, the galvanized wire wrapped around is for the fact that the stator frame is austenitic. I am trying to create an induction motor mainly for learning purposes, though a bonus would be making something good enough to drive a small wire cage fan. Thanks! \$\endgroup\$ Commented Jul 20, 2024 at 21:02

0

Reset to default

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.