Can I bypass the ATV using a bypass contactor that is mechanically and electrically interlocked with the line contactor?
It is possible to use bypass starter with electrical and mechanical interlock. For bypassing with DOL starter, it will require minimum of 3 contactors for drive input(1 No), output(1 No) and Bypass(1 No). For bypassing with Star Delta starter, it will require to use 5 contactors for drive input(1 No), output(1 No) and Star Delta starter (3Nos)
You have to consider the motor nameplate current and power rating for selection of contactor ratings for DOL or Star-Delta starters. You have to select the necessary protections to motor through proper selection of input breaker, fuses and over load relay(thermal or electronic) when the motor runs in bypass mode.