Platter Moment of Inertia
The platter’s resistance to changes in rotational speed, determined by its mass and how that mass is distributed.
Moment of inertia is a rotational property, not simply platter weight. Two equally heavy platters can have different inertia when one places more of its mass farther from the spindle.
Platter Moment of Inertia — Turntable
For a Turntable, platter inertia helps explain how the rotating assembly responds to acceleration and slowing forces. Greater inertia requires more torque for the same acceleration, but it does not independently establish accurate playback speed.
Read the stated unit and the assembly covered by the figure. A measurement may include a particular mat or other fitted parts. The inertia of a separate flywheel should not be presented as the platter’s own value.
Compare matching units and included parts. Weight cannot establish inertia without the mass distribution. Assess it with motor control and measured speed behaviour; a larger number does not automatically mean a better turntable.