The speed at which resonance occurs is known as critical speeds. These speeds are also called whirling speeds or whipping. Whirling Of Shaft Apparatus When the natural frequency of a system coincides with the external forcing system frequency the phenomenon is called resonance. 

Utilities Required:-

•  A dimmer state of 240v, 2amp, and 50 cycles is used to control speed of the rotating shaft.

•  The driving motor is 230V DC 1/16 H.P; 6500 RPM.