A method for storage of excess energy which would otherwise be lost, the regulation of angular velocity, and prevention of excessive velocities is disclosed. The device consists of a bowl shaped container, divided into sections by radially oriented vertical walls, which holds a fluid (any appropriate liquid or set of small solid particles), and spins on its vertically oriented axis at various angular velocities. The floor of the device is formed in successive shapes of bowls and shelves, which allows for a kind of “gearing”. The invention allows more and more energy to be input into the device while the angular velocity is regulated within a particular range. A typical embodiment of the invention would include its attachment by a shaft at the axis to a vertical axis wind turbine.