Low-voltage Circuit Breaker Analysis and Design Using Transient-transient Co-simulation With Electromagnetic and Structural Simulation Software

“Virtual prototyping in Ansys Maxwell software coupled with Ansys Mechanical software makes it easy for us to understand the very complex dynamics inside the arc chamber and to change the design and tolerances inside the arc chamber of our low-voltage circuit breaker to meet the UL 60947-4-1 requirements and minimize the number of physical prototypes, ultimately reducing the time to market. The simulation software also enabled us to get the perfect guidance for the plastic components used in the arc chamber design, which helped us to reduce device cost and improve life cycle and short circuit performance.” 

— Sadashiv Devidasrao Pimple, M.Sc., Project Engineer, Rockwell Automation

Engineering Solutions 

Engineers at Rockwell Automation used a combination of Ansys products to observe and determine the reliability of three-phase CB functions.

By using the coupled transient Maxwell solver to transient Mechanical simulation, relevant dynamics within the arc chamber were observed. Ansys Workbench simulation integration platform was used to couple Maxwell 3D transient solver with the transient Mechanical solver.

The ability to simulate engineering changes within a CB makes the software incredibly efficient in both cost and time savings. The transient dynamics analysis can determine the time-varying displacement, strain, stress, and force response of the structure under a random combination of the steady load, transient load, and simple harmonic load. Moving metal and plastic parts were considered to understand the dynamics inside the arc chamber as well as the magnetic unit. 

Benefits

• Simulations have shown critical aspects in the device dynamic behavior, enabling Rockwell engineers to implement significant changes in the arc chamber design (namely, more guidance for the spring inside the spanner holder and additional ribs to support spanner holder inside H parts). This resulted in a final relevant increment of device performances.
• For further simulation iterations, Ansys spring elements were used to reduce the computational time and achieve faster convergence.
• Simulation results were used to optimize the geometry of the spanner and spanner holder within the CB to prevent blockage during short-circuit and device-tripping tests.
• The winding feature within Maxwell software proved to be very convenient, since the software provides winding inductances, flux linkages, and induced voltages as default outputs for postprocessing purposes.