DC circuit breaker and disconnector

Abstract

A circuit breaker/disconnector apparatus for use in a power delivery system comprises a unidirectional DC circuit breaker which has a first terminal and a second terminal and is configured to automatically open during an overcurrent condition in a forward direction and to remain closed independent of current level in a reverse direction. A disconnector switch is in series with the circuit breaker. The disconnector switch has a first terminal for connecting to a first polarity connector of a power supply, a second terminal for connecting to a second polarity connector of the power supply and a common terminal connected to the first terminal of the circuit breaker. The disconnector switch has at least a first position in which the first terminal is connected to the common terminal and a second position in which the second terminal is connected to the common terminal. The second polarity connector of the power supply may be coupled to a track of a transport system and the second polarity connector of the power supply may be coupled to a live overhead cable or live third rail of a transport system. The apparatus can be used to safely ground the live cable or third rail when in a maintenance condition.

Dependencies are inferred from the claim text.