Medium Voltage Vacuum Circuit Breaker Kinematic Chain Design with Spring Actuator

The spring actuating mechanism is generally used as the operating mechanism for the medium voltage vacuum circuit breakers. Through appropriate kinematic chain, the energy stored in the operating mechanism is converted into linear movement to drive the contacts of the vacuum interrupters in a circuit breaker. Through the kinematic chain, the actuating mechanism drives the contact to complete the desired closing and opening operations. During the operations, the opening spring, closing spring, and the contact spring act together to drive the kinematic chain to achieve the desired mechanical travel characteristics. For reliable operation of the circuit breaker the balance between the energy available in the actuating mechanism and the energy spent in various part of the kinematic chain is important. This paper will discuss the theoretical basis of the energy distribution in the design of kinematic chain, and the design process of a new kinematic chain design, and the calculation method for the energy balance.