Type of winding in a 3-phase induction motor

[UKpete]

While recently investigating a stator winding machine for a mass produced permanent magnet motor, I was told by the manufacturer of the winding machine that for coil inserters (the machine which mechanically feeds the pre-wound coil into the stator slot) the winding must be single-layer concentric, and that lap and other double-layer windings were unsuitable.

This leads me to ask the question (and I guess it's primarily one for the rewind people who see them all the time): are modern LV 3-phase mass-produced induction motors concentric wound? If so, I would assume that this is to permit automatic coil insertion during manufacture.

 

[aolalde]

UKpete:
Nowadays, lots of low voltage random windings are designed for single layer concentric type, just for the advantage of mechanical insertion of the winding. As you already assumed this is to take advantage of automated machinery instead of manual labor.

 

[edison123]

Double layer winding requires the pitch coils (or overlay coils) to be lifted after one round. Obviously, automation is next to impossible in this case and hence single layer concentric coils on mass produced machines.

 

[UKpete]

Thanks for your replies, I wanted to hear it from the horses' mouth (excuse the turn of phrase). I would guess that they are also easier to rewind by hand in that case.