It doesn't matter who built the motor; if it does not receive the juice it requires it will shorten the life. The issue with these emerson motors is well known and I did a lot of research before buying the IR compressor because of this. Reading about this online and talking with IR, this conclusion makes pretty good sense to me...haven't seen too many failures from those running a thicker gauge wire. I know that a 5hp motor typically uses approx 25 amps under load and uses a 40 amp breaker. I was specifically told to use an 6 gauge because of my distance from the box to the compressor, but shorter distances can use 8. I don't know of a reason for this as I didn't get that far into it, quite possibly these motors have a very high initial amp kick. We use slow-blow breakers that will take considerably more amps for a short amount of time, so this wouldn't be instantly noticeable to anyone, but if the wire (power supply into the building, wherever the weak link is) can't handle the high amp draw, the motor will not get the amps it wants on the initial kick.
It has been a few years since I installed mine so all of the numbers are a bit fuzzy, but I believe the initial amp draw was near 100. I was also researching the 7.5hp versions as well, so that number may be for it. In any case, it was over the current carry capacity of a 10 gauge.