The fast vacuum switch with electromagne

tic repulsion actuator as the operating mechanism has such advantages as high opening speed

short opening and closing time and low dispersion of opening and closing time

and at present has been widely used in a variety of power equipment. At present

there are many studies on the opening process of fast vacuum switch

but the problems associated with the closing process are less. In this paper

the contact bounce of the fast vacuum switch in the closing process is studied. A multi-physical coupling simulation model is set up to describe the closing process of the fast vacuum switch completely. The relationship between

v

1

and

D

max

of the fast vacuum switch is obtained

where

v

1

is the instantaneous velocity of the first contact between the moving and fixed contacts in the closing process

and

D

max

is the maximum bouncing distance of the moving contacts. According to this relationship

the critical instantaneous closing velocity

v

cri

in the case of no closing bounce is determined. According to the limitation of

v

cri

a kind of new oil buffer is designed to adjust the closing travel curve of the fast vacuum switch and achieve the non- bouncing closing. A fast vacuum switch equipped with the new oil buffer is developed

and a special measured platform is constructed to test its closing characteristics. The measured result shows that the error between the measured results and the simulation results is no more than 10% and the non contact bounce closing operation is achieved.