The battery pack in an electrically powered aircraft tractor feeds the inverter for the drive systems. The inverter is protected by a fuse and a main contactor. For this task, the manufacturer wanted a bidirectional DC contactor for energy recovery during braking.
As a conventional contactor using air as the insulating medium, it is not at risk of developing leaks, unlike encapsulated or gas-filled contactors. The high current carrying capacity was also a deciding factor. In the selected C310A/500 model, the contactor can carry a conventional thermal current of up to 500 amps; in a short-circuit up to 3,000 amps can flow for one second without the contacts welding.
These are the key features of the C310: