Main contact device of selective protective breaker

The invention discloses a main contact device of a selective protective breaker, which is provided with a bridge moving contact, a contact support and a contact spring of a moving contact point, and a fixed contact of a fixed contact point; the contact spring is arranged in the contact support; and one arm of two arms of the contact spring acts on the moving contact, while the other arm is limited to a pin roll arranged on a shell. The moving contact, the contact support and the contact spring are connected in a normally closed contact structural form; and the contact support is provided with a plurality of coupling structures, and the coupling structures parallelly receive the on-off control of an operation structure, an electromagnetic system and a short-circuit connection preventing mechanism of the breaker on the main contact. The main contact device has simple and reasonable structure, small volume and low production cost; and the main contact can be opened by the electromagneticsystem when a circuit has a short-circuit fault so as to convert the current onto a branch circuit; and more importantly, the main contact can provide stable and reliable pressure guarantee for the connection of the main contact device.