Without anti-creep holes, the interaction of the voltage coil and the light-load adjustment might provide enough torque to cause the disk to rotate very slowly when the meter was energized, but no current flowing.

This creep would generally be in a forward direction, because the light-load adjustment is so designed that it helps overcome the effects of friction and compensates for imperfections of the electromagnet steels. In order to prevent the disk from rotating continuously, two diametrically opposed holes are cut into the disk.

These holes add resistance to the flow of eddy currents caused by the voltage flux. Earnshaw’s Theorem explains that a conductor in a flux field tends to move to a position of least coupling between the conductor and the source of the flux field.

Because of this, the disk will tend to stop at a position in which the anti-creep hole causes the greatest reduction in the eddy currents (sometimes moving backward a portion of a revolution in order to stop in this position). A laminated disk or one of varying thickness will also tend to stop in a position of least coupling.

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