Introduction: Brushless DC Motor Inrunner

Having read the Instructable and being in the possession of a spool of magnet wire (I'd bought to teach my son about electromagnets) I thought, why not give this a go as well.

Here is my effort...


    Step 1: Tools and Supplies


    • Drill
    • Wire Cutters
    • Spanner
    • Soldering Iron
    • 12v Battery


    • Case for Motor (empty shaving foam pot)
    • 12 x M5 / 20mm Hex Bolts
    • 12 x M5 Rivet Nuts
    • 12 x M5 Nuts
    • 25 x M6 / 25mm Washers
    • Length of 6mm Mild Steal Round Bar
    • 30 x 10 x 5mm N42 Neodymium Magnets
    • 26 AWG Magnet Wire
    • DC Motor Controller
    • Steel Epoxy
    • Drill Bits 2, 4.5 & 6.2 mm
    • Masking Tape
    • Sharpie
    • 1mm Wire
    • Solder
    • Electrical Tape

    Step 2: Making the Rotor

    I wanted to make the Rotor quite heavy duty so JB Welded 25 washers to my shaft.

    Originally I was going to use 8 magnets however the strength of the magnets was greater than expected and having put one aside ~25/30 cm away from the other 7 I watched in bewilderment as it slid (at some speed) back across the desk toward the other magnets shattering into quite a few pieces... 4 magnets would have to do.

    Taking a Sharpie I coloured the same pole of each magnet and then JB Welded them North-South-North-South around the rotor (using the plastic spaces they came with to keep them equally spaced).

    Step 3: Making the Stator

    To make the Stator I used an old shaving cream pot. to determine the absolute center I drew round it on a bit of paper and then cut that out; folding it in half and then half again gave me the center once unfolded.

    Putting this back on the top (and then bottom) of the pot using a compass I made a small hole where the center was and drilled a 6.2 mm hole.

    Then I drew a parallel line around the center of the pot.

    Cutting a strip of paper the same circumference as the pot I folded it in half, then into thirds and then finally in half again. After unfolding it showed 11 equally spaced creases. I drew them on so they were easy to see and then using this put 12 marks (including the join) along the line I had previously drawn.

    I then drilled a 4.5 mm hole at each mark.

    Threading the rivet nuts onto the bolts I then put them through the holes (from the inside) and secured with a nut on the outside

    Step 4: Winding the Stator

    On the outside of the Stator I labeled each nut in turn A, B, C, A-, B-, C-, A, B, C, A-, B-, C- and then drilled 2, 2 mm holes next to each one, to thread the wire.

    Having measured 3 equal lengths of magnet wire I took the first one and secured one end with masking tape to the under side of the Stator (and labeling in A+) I started winding;

    1. Through the small hole next to A then 30 turns clockwise round A, back out of the other small hole
    2. Through the small hole next to A- and 30 turns anti-clockwise round A-, back out of the other small hole
    3. Through the small hole next to next A then 30 turns clockwise round this A, back out of the other small hole
    4. Finally through the small hole next to last A- and 30 turns anti-clockwise round this A-, back out of the other small
    5. I then secured the other end with the tape and labeled it A-.

    The same process was followed for the B's and the C's.

    I inserted the Rotor and secured the lid.

    Great resource for motor winding schemes:

    Step 5: Wiring the Stator

    Taking the ends that were labeled A-, B & C- I stripped off the enamel (with a small piece if fine sandpaper) and soldered them together. I then covered in electrical tape to avoid any short circuits.

    I extended the A, B- & C wires with some 1 mm wire, soldering in place and covering with electrical tape.

    The other end of each wire was secured to the controller. I then took 2 other wires from the controller which i hooked up to an old 12 v motorcycle battery

    Step 6: Running the Motor

    After hooking it all up it was time to give it a go and to my amazement ... BOOM ... it worked!