Science~ Will ruin your day..
Dangers
Because of the illusion this can give to moving machinery, it is advised that single-phase lighting be avoided in workshops and factories. For example, a factory that is lit from a single-phase supply with basic lighting will have a flicker of 50 or 60Hz (depending on country); thus, any machinery rotating at 50 or 60 Hz (3000 or 3600 RPM) may appear to not be turning, increasing the risk of injury to an operator. Solutions include deploying the lighting over a full 3-phase supply, or by using high-frequency controllers that drive the lights at safer frequencies.[13]
From Wiki about the wagon wheel effect or the Temporal aliasing theory.
http://en.wikipedia.org/wiki/Wagon-wheel_effect