Allow me to share what I've learned about the me1003. I'm using this motor as a generator, driving it with a vanguard 18hp engine to charge a 48 volt battery bank. At 4.8kw the me1003 begins running very hot. I measured the temperature with an IR gun and was reading about 180 degrees F (on the motor case). This with an 8" fan mounted to the back of it. I then realized, using the me1003 as a generator changed the brush timing even though it was still turning CCW. I adjusted the brush timing to the CCW direction and me1003 temperature dropped to around 160 degrees F. I know the insulation rating for the me1003 is about 300 degrees F. But, the hotter the motor runs the greater chance of magnet damage. I know the overall rating of the me1003 is 250 degrees. Seriously, do you really want to run something made in china that hot? I don't. So I made a heatsink from 1/2" aluminum angle, mounted it to the me1003 (with heatsink grease) and built a shroud between the fan and the me1003. This helped direct the air over the heat sink. Until now all measurements have been made with an ambient temp. of 70 or less. First test run today with fan, shroud, heatsink and 80 degree ambient at 4.8KW.
Case Temp. = 104F
Winding Temp. = 137F
For those running the ME1003 hope this helps.