Quote:
Originally Posted by johnrobholmes
I don't know if theory alone can explain this well, there are so many variables. When any phase is excited, delta energizes all three coils at a time whereas Wye only excites two. If kv is the same between termination styles the amp draw will be the same, and since kt and amp draw will be the same the motor torque will also be the same.
Change the magnet count or stator count- motor power will change. Change the size of the motor, motor power will change. Change the winding of the motor, motor power only changes in respect to voltage.
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Yes, there are many variables.
Total Power output also changes in respect to Amp draw. Total watts of power.
The way I understand it, on a 12 pole motor:
A Delta Winding has 4 poles energized at a time.
A Wye Winding has 8 poles energized at a time. but they are 4 x 2. 4 sets of 2. The amp draw is lower for identical turns because the pairs of windings are in series to each other. This drops the amp draw by 1.73 times along with the kv. but raises the torque by 1.73 times.
I guess what I'm really wondering is, if we drop turns to raise the kv back up in a wye winding, will we retain the added torque bonus along with the improved EMF feedback?
Here's what Lucien had to say about this when we were discussing a high kv wind on a 4045 Scorpion motor. (note: 700kv wye wind will be easier on a 4130)
Here's what I asked him:
"Would it be possible to wind a 4045 to around 800kv using larger diameter wire, such as 22 awg, using a wye termination for a 1.73 torque bonus? (Minimize copper losses and keep operating temps to a minimum?) I noticed that with a wye termination, it uses 8 magnets, 8 poles at any given time. I'm not too concerned about amp draw or total efficiency at this point. I'm just looking to have some fun and learn more about 3 phase windings and how they perform."
Here's his answer:
"It would be very tough to wind a 4045 with a Kv of 800, especially with a Wye wind. THe current 4045-10 has a Kv of 360, the 4045-12 has a Kv of 315, and the 4045-17 has a Kv of 270. These are Delta wind motors, so if you switch to a Wye, the Kv will be lowered by a factor of 1.73. A 4-turn Delta would have a Kv of about 800, but you would have to wind about 50 parallel strands to get enough copper in the slots.
The larger motors are made to run on 10-12 Li-Po cells to be able to get enough power to run the motor, and that is why they have a much lower Kv.
Think that over and let me know what you think."
I keep notes on all the information I've collected.
Now keep in mind that the 50 strands that he is referring to is 31awg. Total Cross Section area of the wind and total resistence is what we need to look at. In other words, we can use a much larger Ga. wire and eliminate the whole 50 strands thing.
I'm sure the end product of what I'm trying to put together will DEFINATELY be a high amp draw motor. But that's ok, that's what I want. Total Watts is Total power.
I want to run this on 4S Lipo or more. It's ok if it draws 100 to 150 amps continous.
I asked AXI about motor kits for the people who want to wind their own motors. Maybe they have those.