EDO Model EDF64 4300Kv

This fan unit powers the EDO Models F15 Eagle and F4 Phantom, and various Starmax/ExceedRC '64mm' jets (the fan's actual inside diameter is 63mm). Fan loading and performance is almost identical to the GWS EDF64. On 3S the 4300Kv inrunner motor has reasonable efficency but is working very hard, so it might be prudent to add a 20mm heatsink.

My unit showed evidence of rubbing. The impeller was not centered in the duct, and the blades were all slightly different lengths. Before running the motor in the fan I sanded the blade tips down using my usual technique (hold a piece of fine sandpaper inside the duct, and turn the impeller by hand until the blades stop scuffing). To check the dynamic balance I ran the motor up slowly, while feeling for vibration and/or blade scuffing. At about 1/4 throttle I could feel and hear blades hitting the shroud, so I stopped and removed the impeller for balancing.

Unfortunately, at this point I noticed that the motor was now graunchy and hard to turn - something was wrong inside it! With the application of heat and lots of 'elbow grease', I managed to unscrew the endcap without completely destroying the motor. Apon removing the rotor I found that a ball of solder was stuck to it, and this had been scraping on the windings. Luckily, after re-assembling the motor it still ran at the same no-load rpm and current, so my repair was successful. Final balance was achieved with two pieces of electrical tape stuck inside the impeller hub.