1512/1.5Y vs. 1512/2.5D?
 

I have narrowed it down to one of two to go in my MBX-5 on 4S. So can any body say what the differences are between these motors besides the KV rating? I read the 1.5Y is more efficient but I couldn't find that on Neu's site. Also what is the difference and/or reason for the Y and D winds?

Stephen.

Where did you read that the Y is more efficient? AFAIK, it's just a way to get different KVs at the same number of turns. A Y motor has a KV that is 1.73x more than a D of the same turns count, but the Neus seem to depart from this formula - maybe it's just them rounding the kv values...

http://www.flydma.com/catalog/index.php?cPath=1_2_15

Oh, I see now. As you can see, efficiency goes up when less current is used. Even the D motors increase efficiency as KV increases.

I asked neu/dma about the d vs. y thing last summer when I first got a neu.

The guy at dma said ther is no difference... that one type is not "better" than the other. But then he's not Steve Neu either.. he is only a distributor.

I would pick the kv you want and not worry about which style wind it is.

Hey you could just get a bigger flywheel for the motor you have now:005:

btw, I have the 1.5Y and I'm very happy with it... but I would also not blink twice about getting a 2.5D if I needed another one and that's what Mike had in stock.

I just emailed Neu. I don't know if they have time to respond but I asked them the differences between the 2 motors as far as Y vs. d wind and efficiency. Mike can get any motor I assume?

Yes.. if it's in stock at dma/neu

Motor with best efficiency is the perfect balance between copper and core losses. Copper losses associated with current and core losses with voltage. While it is easier to see copper losses (heat) it is not that easy to observe core losses.

So, it would be difficult to see much difference in efficiency among two motors because they run at different voltages and currents. If you compare under the same conditions they both will be not good, but if you put one in sweet spot then another will be in opposite.

Bottom line select you motor based on your gear ratio, battery voltage, ESC used and driving preferences.

Copper losses and core losses would BOTH be heat.

This just has to do with these types of motors, there are many more motor technologies emerging now, although not in production yet, and not for RC, yet. The day will come when we have AC induction motors for RC, RaserTech has a wonderful new type of Induction motor with 4x the power of regular Induction motors. They would have much better lower end efficiency, like lower toque, which these BL motors are conditionally resistant too.

It is true for heat but it is not clear when they happen, because then current doesn't transfer in torque.

Induction motors have their limits as well, and it is war against small percentage in efficiency, which is important for constant velocity applications, but for RC systems with wide dynamic range it would be very difficult. The complexity of control electronics will defeat benefits in efficiency.