I'm currently working on designing a permanent magnet synchronous generator for one of my personal projects and I'm having trouble getting a voltage I am satisfied with. My goal is to get around 4-6 V atleast. I have 3d printed a protoype and I do understand once I get a metallic core and such that my flux with increase however I'm just wondering if any of you have any tips for designing this. I want it to be 3 phase and my magnets right now are very weak I have n52 magnets that I ordered coming in soon. In the photos below, those are my two prototypes, the one on the left has 300 turns each and the one on the right has 200 but manages to get more voltage, must be due to airgap. enter image description here

  • \$\begingroup\$ Because you are making a core and coil of completely arbitrary dimensions, I'd suggest taking advantage of that and ordering completely ideal magnets (Perhaps arc magnets), and also consider whether your dimensions permit a Halbach array. When you're making 3D prints like these to test, consider whether you can leave at least some voids in your coil centers to add some high permeability material and/or size the outside of it to fit the whole thing inside a ferrous tube of some sort. Not nearly as good as proper laminate silicon steel frame, but still much better than plastic. \$\endgroup\$
    – K H
    Feb 26 '19 at 4:34
  • \$\begingroup\$ At the moment, you're running with 100% of your magnetic path as airgap, the flux will be very low. Once you have iron cores for your rotor and stator, you might get the airgap down below 5% of your flux path, with a corresponding 20x improvement in flux and 20x in output voltage. The effect of the aspect ratio difference you observe between your models (they might be space models, but they're not in any sense electrical or magnetic prototypes for generators (sorry)) will be irrelevant once you have a proper, nearly closed, iron flux path, with minimal airgap to allow rotation. \$\endgroup\$
    – Neil_UK
    Feb 26 '19 at 5:13
  • \$\begingroup\$ One option if you're unable to find a service to cut and coat silicon steel plates for you is to salvage parts from an existing motor. Tricky part is finding a smallish motor that can be disassembled easily and has magnets the shaft or both field and stator windings. BLDC motors are likely targets. The main point of doing this would be to rewind the motor as a harder-to-source motor like a low RPM generator for wind/water generation without a gearbox. You may be able to access metal CNC machines at a local makershop, but silicon steel may be hard to source and also hard to cut. \$\endgroup\$
    – K H
    Feb 26 '19 at 6:13
  • \$\begingroup\$ Any recommendations on the gauge of wire? \$\endgroup\$
    – jay rivera
    Feb 27 '19 at 0:23

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.