I'm not a full time scrapper but I sometimes do scrap and break down some motors for the copper content and I find that I gain around $1.00 to $4.00 more by breaking down a motor and the small motors take me around 15 minutes to break down while the larger ones take me around 30 minutes each.
So at that rate on the larger motors I'm making around $8.00 per hour which is a bit more than minimum wage here.
So in my opinion some electric motors are worth breaking down for scrap if you have no other job or nothing else to do otherwise you may be better off selling the electric motors as is and be done with it.