An electro-dynamo wheel is a power generation device of Luminoth creation. Although several mechanisms appear throughout the Sanctuary Fortress, only one of these devices can be scanned, in the Temple Transport Access room. When scanned, it is revealed that this unit is part of a power-generation system that powers the Fortress. The wheels are locked in an automated cycle.
"Object analysis complete. Target is part of a power generation system. It appears to be a massive electro-dynamo wheel. Unit is locked in auto-run cycle."