Abstract: Spring Operating Mechanism (SOM) is a dynamic mechanical system to open and close high voltage circuit breaker in electric power controlling system. For opening and closing within a few mili-seconds, it is highly sensitive with speedy transmission and great reliability. With the clearance joints and flexural deformation, the SOM will generate high-frequency vibration due to transient impact. It has complicated wide-band nonlinear dynamic features. To save time and money for a new design and analysis of SOM system, a flexible dynamics model of the SOM with multiple clearances and dry friction is established. Also, an experimental platform is built to measure the displacement and velocity of the moving contact in opening and closing. The reliability of modeling is validated through the comparison with test data. In addition, the effect of friction force on the flexible SOM with clearance is investigated. It can be concluded that the increase effect of the friction force has a significant effect on the dynamic responses of the mechanism with clearances.