A Longitudinal Magnetic Field Of 1/2 Turns Of The Coil Electrode Structure Of Vacuum Interrupter

The constriction performance of vacuum electric arc at high current levels depends on the contact material and its operational principle. Axial magnetic field (AMF) contacts can prevent the vacuum electric arc from shrinking in the vacuum interrupters. AMF contacts can provide an excellent performance of breaking short-circuit current because the diffuse arc has an small effect on the energy of electrodes. According to the different contact design, the distribution of axial magnetic field is different. The direction of the AMF for single-pole contact is the same within the whole inter-electrode gap, and it changes for the multiple-pole contact.A new double-pole axial magnetic field contact design and its characteristics are introduced . The double-pole AMF contact not only can generate very strong AMF but also has better fielduniformity. It is applied to the vacuum interrupter which is in the high rated short-circuit breaking current with the high rated current.The basic operational principle of the new contact design is researched. The contact design provides two areas with nearly the same axial magnetic flux density distribution (by amount), i.e. two areas with equal conditions are given.The integral method is adopted caculate and analyze to AMF three-dimension distruction which is the structure of coil type four-pole and the structure of coil type double-pole and study the size of two kind of electrode structure axial magnetic flux density distribution and its fielduniformity.The Finite-Element method is used simulate that eddy current has effect on AMF when contact tray of douple-pole AMF structure is slotted or no. The analytic result shows the higher fieldunification is produced between contact gap by the coil type double-pole AMF contact structure, and its intension is over 2 times than quadrupolar contact structure when they are in same current. The effective area of two-pole structure is greatly improved to quadrupolar structure. It can still decrease influence of the eddy current greatly while contace surface of coil type double-pole AMF structure is not need to be slotted, so it can also decrease surplus axial magnetic field when the current is at zero and axial magnetic field hysteresis time. Adopting the short circuit electric current of to formate the test prove that this contact turn on and cut off performance. According to ablation situation of contact surface after testing, have analysed that coil type double-pole AMF influences electric arc...