Extra set of phase wires on ebay motor, purpose?

Hello. I've been using a couple DD ebay motors for a little over a year now and finally opened up the 1200w one. The 28amp 48v controller is next to it waiting for a very small shunt mod. It also is marked 8 x 226 and ht-15. So it looks like 8 turn. It's good for about 32 mph with a 12s 18ah lipo

Question is. Why do I have an extra 3 phase wires on the upper left side? They are not hooked up to anything and tied down neatly. The messy ones on the bottom run through the hub and to the controller.

that's where the ends of all those windings get connected together. your motor is wired Wye. It's the center point of this diagram.

Thanks drunk. I thought I understood how these motors worked but now I got some learning to do on Delta vs wye. And some reading to do on your build thread!

Each one of the three motor phase groups has two ends to it, so there are six wire ends to the phase groups. However, in order to run the wires from the inside of the motor to the outside to the controller (there are a few models of hubmotor that have the controller inside the motor housing, Stromer, A2B, Magic Pie), but most have the phase wires exit the motor near the axle.

Instead of having six wire ends exit the axle, you can use thicker wire if you terminate three of those six wire ends inside the motor, and only three need to exit. Electricity will only flow through a complete circuit, so it doesn't hurt to have three of the six phase group wire ends connected.

If you look, you can find one-phase motors, where all of the coils are energized and then de-energized at the same time. Not as smooth as multi-phase, but they can be run by a very simple controller. There are motors that have two phase groups, where it uses a simple one-phase controller, but the second group of motor phases are powered by a "delay" circuit. Crude, but works "OK" at a specific and constant RPM.

Falco bundles their motor phases in groups of five (5-phase), and theoretically it is smoother and slightly more efficient than 3-phase, but...you can only get controllers from Falco.

Fisher and Paykel makes a 7-phase motor, with a high pole-count (for washing machines, its popular to convert to a small wind-generator).

Three phase is smoother than one-phase, and simpler than 5-phase (or more). The biggest benefit is simply that 3-phase is so common, the parts are cheaper due to mass-production.

usertogo said:

I have been thinking, since recently I got a motor that was repaired incorrectly (the axis was replaced with a newly turned one where no slot was cut for power leads!). And the thought is what if one could replace one motorcover with one that gives room to a larger diameter bearing so I could run the 6 leads of all 3 windings out independently.

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Using a larger bearing, with a "spacer" ring on it's ID to allow very thick phase wires individually passed thru it, has been discussed several times, though I can't remember if it was ever actually completed by anyone.

Then if using a controller with 6 complete FET driver bridges wouldn't that potentially be much more efficient? one could really independently choose which winding gets which polarity, and even a partial winding fault might not be as much of a show stopper as normally? If one wanted there could also be extra FETs for a programmable 'delta-wye' switch?
Has anybody ever done that?

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I havent' seen that done yet; you'd need to design your controller around doing this, from scratch. I suppose you might work with Lebowski to see if his brain software could be modified to do what you want (or run a pair of them communicating with each other to do it).

I don't know if it would make anything better in any way or not, but the experiment would be interesting to see the results of.

I also thought about investing some thought if any more than 3 Phases could be identified to give a motor an even smoother angle progression?

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Yes, there have been a number of multiphase motors. There is a 5 phase (Falco) and a 7 phase (TidalForce) that I can think of, out of ebike motors at least. But a higher pole count does this with 3-phase, AFAICR, without complicating the phase-driving.

Anyhow just curious has any of this been explored? Thanks for your time!

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There's a lot of threads in the Motor Technology section about various motor / controller mods and ideas, but it is probably quite a lot of looking thru pages of thread titles to find them, since I don't know any way to easily search for this stuff using the PHPBB search engine.

Over-side bearing with collar around the shaft drilled to pass thick phase wires through has been done, I've seen it somewhere on this forum before. Might have been a magic-pie motor.

6-phase motors do exist (check out posts by johninCR, he uses large 6-phase motors). The efficiency again by going to extra phases compared to a well-designed 3-phase motor are apparently miniscule. Delta/wye switching doesn't make the motor itself any more powerful or efficient - it's not gearing. But it might let you use a weaker controller to get the same peak torque output (with the added complexity of the switching gear). The main advantage of 6-phase motors is you can use two common, inexpensive 3-phase controllers ganged together, rather than a single controller trying to run twice the phase current.