ZN28-12 and ZN28A-12 indoor HV vacuum circuit breaker applies to power system of rated voltage 12kV, three-phase AC 50/60HZ. It used to control and protect electric apparatus in industry like mining, substation and so on. ZN28-12 is a unitary type (operation mechanism is installed inside the switchgear and combine with it as a whole); ZN28A-12 is a hanging-on type (the mechanism and switchgear are seperately installed on cubicle or support frame, then connected with link rod and drive shaft.) It conforms to IEC62271-100, GB/T1984, JB3855 and DL/T403 standards.
1、The vacuum arcing chamber of this VCB is of middle sealed-in longitudinal magnetic field type.
2、Whten the stable and moving contact open by the performance of operation mechanism,the arc in vacuum occur between contact,then extinct when the current reach at zero.
3、The VCB applies to rigorous occasions such as high altitude and frequent operation.
4、As long as the VCB accord to the mechanical characteristics, the client may select adaptable electromagnet or spring operation mechanism according to special situation.