Quote:
Originally Posted by gpetilli
I believe the 775 has a bad reputation because many teams block the air input vents. This is largely because many of the gearboxes (banebots and AndyMark CIM-Sim) cover the input air vents and the motors overheat. One year we used the banebots gearbox and ultimately machined channels in the gearbox mounting face (look at the VersaPlanetary mounting plates) and that made a HUGE difference in the temperature of the 775 motors.
If you do use the 775 in your drivetrain (or anywhere else) absolutely make sure it is well ventilated. If you use the CIM-Sim at least drill some holes in the plate where the motor mounts to allow air to enter the input vents.
That said, the drivetrain is arguably the most important subsystem on your robot. Do a risk/reward analysis before moving from the miniCIM to the 775. Is there anyplace else you can save a few pounds?
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775's have another black mark against them - that's the shorting issue teams had when they were first released. There's nothing more frustrating than having to repeatedly change out 775 motors during inspection because of internal debris causing shorts that ground your PD board.
We haven't used them since that year. Fool me once, etc. Many other teams have used them since then.
We used 550's very successfully on our drivetrain in 2008. That year, however, you were generally trying to drive at full speed. This year, there is a lot of slower-motion movement aligning, adjusting, and setting things down. That means that any low mass air-cooled motor is not going to be terribly happy. Active cooling on the motor (a fan) will help tremendously.