Step by step guide to rewinding your 1100kv/1500W motor!

[Kailee]

… pushed the tape right into the slots. A bit tricky, but it will protect the insulation on the wire whilst laying it down into the slots.

[Kailee]

Unconventional as i am, I hold the end of the wire I work with in a small vice on the floor (it'l come up between my legs as I wind more an more wire onto the stator), and I hold the stator free in my hands. This is my first wind, so bear with me! next time, I will try the conventional way of clamping the stator and doing the winding with the wire wound on a piece of round wood…

[Kailee]

First phase, first tooth done!

[Kailee]

I leave the ends sticking out the back until the three phases have their first tooth complete, then I bring the ends forward as I move on to the next tooth.

[Kailee]

The first half of the stator done. I made the same mistake as with the test wind, the starts of the three phase sit jammed to the inside of the slots. I think it might have been tidier to leave them free on the outside of the slots, but I'm not going to unwind now!

[Kailee]

A picture of those little strips of pvc and how they keep the slot tidy. if you cut them right then they stay in the slot with a slight bit of stiffness, so you don't have to hold them whilst handling that stubborn wire…

[Kailee]

Here you can see another little helper I created after half an hour's winding; my fingernails were beginning to complain about pushing the wires down into the slots, so I just cut a small length of PVC angled profile to do the pushing down with. Shoulda done this at the start, it really makes it much easier to put some force onto the wire to pack the down into the slots.

[Kailee]

All the phases are on. Wow, what a feeling of accomplishment! Now's a good time to check for shorts between the phases individually and also between the phases and the stator. If you don't get any beeps from your voltmeter, press on!

[Kailee]

This is a view of the back of the stator. This side should look much tidier than the front (and it does), but I'm only happy with it because this is the first time I did this. A few of the wires aren't quite straight, but hey, I'm a beginner. also, when I look through the slots end to end, some have some space, one or two even enough to stick one more wire in, but nowhere near enough space to put a complete turn (two wire per slot!). So, in terms of filling the slots, I'm quite happy. I hope there's enough of a gap to allow some cooling air to spass through though… Anyway, I do believe that the slots aren't all equal...

[Kailee]

Also, not unimportant; after winding all the phases, see how the ends line up. Hopefully you cut the wires to the exact same length, because it allows you to see if you wound them equally. A little off here as you can see, but again, the best I could do this time.

[Kailee]

Time to reassemble. I wanted (needed?) the choice of how to connect the phases, i.e. star or delta, and chose the more conservative in terms of kv star configuration for the test runs. I left the ends quite long so I could still do something with them should I need to, then just soldered them together, put some 3.5mm connectors on the starts of the coils. Then a few bits of glass insulation tube and off we go.

[Kailee]

The stator pack has a few grooves running down the inside. One of the deeper ones comes in very handy, as there's also a groove on the stator carrier - line them up when you reassemble and you can stick a 1.06mm piece of wire down it to counteract the torque. Originally I could find no such wire, it was just glued using (I assume) loctite…
You can just about see the end of that piece of copper wire protruding between the stator and the carrier.

[Kailee]

Now make sure you clean out the bell, mine had lots of gunk and dust in it. not surprising really considering what it had been through in it's last active moments…

[Kailee]

Done! As you can see this motor has been used with a planetary gear, a 3.7:1 Plettenberg, which has so far withstood enormous amounts of abuse without even a scratch. Hopefully, my little Hurricane motor is now as robust as the gearbox! One last check for shorts between the phases and the casing, but found nothing wrong, so I connected up my logger, my ESC, a 5s battery and slowly applied some voltage.

[Kailee]

Hopefully it runs! And it did so smoothly too, so I did a few short runs to full power, and then shut it down again. It turns out it ran to 20.2V at 16250rpm with 2.2A, so a slice above 800kv. Over the next few evening I'll reconnect the phases as delta, which should raise the kv to 1400 or so. Hopefully, by the weekend I'll have some new bearing (I don't trust the old ones to fly) and will be able to do some flying with this newly refurbished motor. I'll post some more logger data of those when I get them over the next few days. For now though, it's a complete and working motor again, and has given me a number of interesting learning experiences, and a HUUUUUGE sense of accomplishment. On to the next motor - a Mega 22/20/3E that I burned out recently!

[Kailee]

... so post away. Hope this is of any use to anyone, and that someone somewhere is now thinking "now, why don't I try doing this?"....

Hope you enjoyed this, I'll be back soon with an update when I changed it to delta, and then again when it's been in the air.

Bye for now,


Kailee.

[spootman]

Nice job!

[JimLerch]

Excellent write up! Congrats, and another neat trick with this is you can select a variety of Kv values not only by number of turns but by selecting star (wye) or delta connections. Wye is slower than delta given the same number of turns..

Winding your own motors opens up a whole new dimension in motor selection!

[Mikej]

Fantastic write up - good work fella

[Borneoben]

Many thanks for taking teh time to share with us your experience its very interesting.

Can you explain a couple things for me..

What is the purpose of adding teh extra layer of GRP on the top of the stators?

How did you calculate what number of turns to use and what size wire?

Thanks again

I look forwrad to hearing your results

Ben