Brushless DC Motor Inrunner

Having read the Instructable https://www.instructables.com/id/Make-A-Brushless-... 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...

Tools

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

Supplies

• 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

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).

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

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:

https://www.bavaria-direct.co.za/scheme/calculator...

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

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