To solve the problems of three-position disconnector

such as complicated structure

large space occupa-tion

inaccurate positioning

and need for later adjustment to achieve positioning accuracy

this paper proposes a posi-tioning scheme for a cylindrical indexing cam structure. The cylindrical indexing cam mechanism has the advantagesof simple structure

high positioning accuracy

and multiple indexing numbers

and can meet the design requirementsof the operating mechanism of three-position disconnector. Firstly

the positioning principles of the existing operat-ing mechanisms of three-position disconnector are analyzed and compared

and corresponding problems are pointedout. Secondly

the theoretical analysis on the positioning principle of the cylindrical indexing cam structure and proto-type design are carried out. The test results on the prototype show that the scheme is simple in structure

small inspace occupation

and the required positioning accuracy can be achieved without adjustment after assembly. Andthis positioning scheme can realize accurate positioning of the three-position disconnector’s electric operation

andmeet the requirements for miniaturization and high reliability of gas-insulated metal-enclosed switchgear. Thisscheme has been widely used in engineering.