I've had many after market single phase condenser fan motors overheat. In most cases the amperage of the motor was marked as slightly lower than the OEM and the motor was physically smaller than the original.
When I replaced it with a motor of the original size and amperage the issue went away.
I suspect the heart of the matter is many after market motors are nominally rated. It saves a few bucks during manufacturing and works well in the field.
I don't alway use OEM, I do try to match HP and amperage.
I have had good results with the rescue motors as long as the fan blade would position properly in fan shroud. That being said, the after market motors are the only ones I've seen that came apart after several years.
BTW, not all OEM motors are more expensive. This week I priced a 3/4 hp 3 speed 460v 1 phase blower motor on a Lennox package unit, the OEM from Lennox Parts Plus was $90 cheaper than the after market at the local motor supply house.
I am for doing good to the poor, but...I think the best way of doing good to the poor, is not making them easy in poverty, but leading or driving them out of it. I observed...that the more public provisions were made for the poor, the less they provided for themselves, and of course became poorer. And, on the contrary, the less was done for them, the more they did for themselves, and became richer.
― Benjamin Franklin