DC power technologies such as renewable energy, data center, and EV are rapidly spreading in recent years. These technologies consist of DC power, and the demand for DC systems is increasing. Improvement of DC circuit breaker performance as DC system protection is being demanded more than ever. In this research, we describe a method of forcibly creating a current zero by applying a magnetic field in order to interrupt DC current with a vacuum circuit breaker. In condition when the external TMF (transverse magnetic field) was applied to vacuum arcs, the relationship between DC current and arc's motion are investigated. When a transverse magnetic field is applied to the vacuum arc, the arc moves on the electrode surface due to the influence of the magnetic field and extinguishes. The manner in which the arc extinguishes is classified into two patterns depending on the magnetic field and current conditions. The current was quickly interrupted as the strength of the magnetic field was increased. In the experiment, the vacuum arc is ignited in a vacuum chamber under transverse magnetic field application, and the state of arc was observed by high speed camera.
