motors manufactured by robots

[spinningmagnets]

We've all seen the video with the rooms full of ladies with slender fingers wrapping copper wire around the stator-teeth. I've been curious for a while about "high end" electric motors where automation would someday be applied to the assembly of motors.

Porsche 918 Spyder hybrid (BLDC permanent magnet outrunner/giant RC scale?)

https://youtu.be/ZSiR5quGMi8?t=374

BMW i3 electric car (stator is shown immediately, rotor at 3:40, permanent magnet inrunner, see how the rotor sections float at 4:14)

https://www.youtube.com/watch?v=x3brfAEs_RY
[youtube]x3brfAEs_RY[/youtube]

Looking for an assembly video of the GM Volt "hairpin" style motor (easy to wind?)

The smaller "Chevy Spark" motor is also a hairpin style. by using high volts, it provides good torque from lower RPMs, which apparently allows GM to use a permanent magnet rotor, or...to swap to an induction rotor with no changes to the power or the size/shape of the inrunner stator (plus no changes to any potential oil-cooling shroud). They seemed to indicate that IF they had used lower voltages, there was a definite advantage to permanent magnet motors, but... they had a fear of China restricting trade on rare-earth magnets in the future. So, by going to high voltage hairpins, they can use permanent magnets while they are available, and then switch to induction rotors if they have to.

http://endless-sphere.com/forums/viewtopic.php?f=34&t=58465&p=873425

 

[speedmd]

Looks like the BMW inserts small magnets in the smaller of the two rectangle openings nearest the gap diameter in the rotor. Interesting looking cut outs in the core. Just guessing, but it looks like they are tying to magnetically isolate the inner steel structure from the steel around the magnet possibly to reduce iron losses. It also looks like it reverses magnet polarity between adjacent magnets with the wrap around rays of steel.

 

[spinningmagnets]

That is excellent info. The results are visible, but there is no posted data as to why the odd shapes are laser-cut into the lams

 

[learningrc]

The stator assembly in that first video is fairly typical even for not-so-high-end manufacturing processes. Typically for induction motor stator assembly of this type, there will be one machine for winding coils and another machine for inserting the coils into the slots. A human operator will transfer the coil from one machine to another. Then they will be transferred to another machine for lacing. So the BMW assembly gets rid of the human operators that would do the transferring from one machine to another. But other than that, the basic winding/inserting/lacing processes look pretty standard.

Here is what I'm talking about: [youtube]__8mjoquDsg[/youtube]

 

[learningrc]

Just guessing, but it looks like they are tying to magnetically isolate the inner steel structure from the steel around the magnet possibly to reduce iron losses.

It is probably not so much to reduce iron losses but rather to saturate the steel to get the saliency/reluctance torque that they want. The steel between the different cut-outs is usually called a "bridge" and flux density in the bridges can change, depending on the current in the stator.

 

[speedmd]

Just guessing, but it looks like they are tying to magnetically isolate the inner steel structure from the steel around the magnet possibly to reduce iron losses.

It is probably not so much to reduce iron losses but rather to saturate the steel to get the saliency/reluctance torque that they want. The steel between the different cut-outs is usually called a "bridge" and flux density in the bridges can change, depending on the current in the stator.

Several auto e motors use this style of having magnets inserted internally in the core. Would think it creates less torque not having the magnets at the gap. Would also think the "Bridges" of steel between spaced out magnets would also make the motor less power dense. Not sure what saliency or reluctancy torque are or do for the performance. I see a new thread forming. It is interesting the way they physically remove most of the connective steel behind and around the magnet pocket steel and bridges. Would love to see the flux contours / simulation to see what is happening.

 

[neptronix]

Wow!
I wonder if the wire wrappers will miss their jobs?