You should probably know the 7520 version of that motor is not the standard silver can. 75 refers to the wire size and 20 to the number of turns. Silver cans are the 6527 model. The black can is a 23t. If I recall correctly, the wire number was around 72.
I tested a 7520 once in a mini with stock gearing. It got REALLY hot and the torque was garbage. Good motor for a vacuum cleaner, though. I've also got an as yet unidentified silver can that spins to 30,000rpms at 6v and the brushes aren't even seated yet. Torque is also not the strong suit.
...and this is why spec brushless systems are taking over. Too many silver cans out there. I do miss them, though.
Last edited by monkeyracing; 08-17-2012 at 01:27 PM.