As far as I know, AC motors can have brushes too, but the Leaf's motor does not being a permanent magnet type.Herm said:You would need a brushed motor.. lots of maintenance and brush dust issues.. and a bit harder to get rid of the heat since the winding would be on the rotor spinning around. Awful..
There are a bunch of inaccurate statements being made in this thread about AC vs DC, not all DC motors have brushes and there are many varieties of AC and DC motor designs, etc, there is plenty of tech info on the web on various types of AC and DC motors and variations of each and their pros and cons.
Thanks for making a useful contribution to this thread!EVDRIVER said:There are a bunch of inaccurate statements being made in this thread about AC vs DC, not all DC motors have brushes and there are many varieties of AC and DC motor designs, etc, there is plenty of tech info on the web on various types of AC and DC motors and variations of each and their pros and cons.
Electronically commutated motors, rather than brushes. The most common type I'm familiar with is PC fans; the rotor is a permanent magnet and the stator is on the inside. A hall effect sensor senses the polarity of the rotor magnets as it rotates and some transistors switch the current in the stator windings.Herm said:Andy refresh my memory, an example of a brushless DC motor?
The 5kW hub motor in my motorcycle is PMAC/BLDC. It's fed three-phase AC thru an inverter. Not that I would ever do such a thing, but if someone were to take it apart, they might see this:Smidge204 said:Electronically commutated motors, rather than brushes. The most common type I'm familiar with is PC fans; the rotor is a permanent magnet and the stator is on the inside. A hall effect sensor senses the polarity of the rotor magnets as it rotates and some transistors switch the current in the stator windings.Herm said:Andy refresh my memory, an example of a brushless DC motor?
Though I've never seen a high HP one I'm sure it's possible and I wouldn't be totally surprised if they exist in multi-HP sizes. I'm skeptical they make them "car sized" though... at that point the power electronics and controls are such you might as well go with an AC motor.
=Smidge=
Which I suppose prompts the question: What's the real difference between a Perm-Magnet AC and a Brushless DC motor? Answer: control scheme.AndyH said:The 5kW hub motor in my motorcycle is PMAC/BLDC. It's fed three-phase AC thru an inverter.
6.3.2 The brushless DC motor
The brushless DC motor (BLDC motor) is really an AC motor! The current through it alternates, as we shall see. It is called a brushless DC motor because the alternating current must be variable frequency and so derived from a DC supply, and because its speed/torque characteristics are very similar to the ordinary 'with brushes' DC motor. As a result of brushless DC being not an entirely satisfactory name, it is also, very confusingly, given different names by different manufacturers and users. The most common of these is self-synchronous AC motor, but others include variable frequency synchronous motor, permanent magnet synchronous motor, and electronically commutated motor (ECM).
Herm said:Andy refresh my memory, an example of a brushless DC motor?.. the ones I use in my RC planes do use DC, but they use an inverter to generate a 3-phase AC waveform.. these motors look suspiciously like the motor in the LEAF.
The reason you dont use classical DC motors is rotor cooling issues and brush losses and maintenance.
Nubo said:The controller responds quite nicely; you can feel it respond with additional power when the blade starts encountering resistance (tall grass, etc). Only seems to use as much power as situation calls for. Gets quite a bit of work done for the amount of battery it has (2x12vx20Ah)
China's not the only source of these not-rare earths.Herm said:LOL...
Probably the reason they did not use a DC motor is that they are more expensive to manufacture.. now you need a commutator and brushes.. to save a bit of money on the inverter.
The real issue is why Nissan used a motor that is dependent on rare earths from China?.. when its so easy to use a magnetless motor like Tesla and GM uses.
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