Increasing the value of the motor from Castle?

[Pdelcast]

Originally Posted by What's_nitro?

To what degree would using ferrite magnets affect the efficiency of these motors? They have about 1/3 the field strength of neo magnets, but I imagine they are less expensive since no rare earth materials are involved.

I'm sure the CC engineers have already looked into other options, I'm just curious. :)

Ceramic ferrite magnets are cheap, and readily available.

However, the field strength is very low, so the torque is only about 1/3 that of neodymium.

In practice, to get the same Kv from a motor with ferrite magnets would require 3 times the number of turns per pole.

For example, a 1410-3Y ferrite motor would have approx. the same Kv as a 1410-1Y neodymium motor. But, instead of having 7 milliohms of resistance, it would have 60 milliohms of resistance.

A neodymium based 1410 motor would lose 12 watts of power to resistance losses at 40A (40^2 * .007)

At the same loss level (12 watts) the ceramic motor would be only able to handle 14A.


So -- reducing the power of the magnets by a factor of three, also reduces the power of the motor by a factor of three.


In practice, you can assume that the power to weight ratio of a ferrite based motor is only 1/3 that of a neodymium based motor.



I know, it's a shame... But to get the same power would require a motor three times heavier.