Rockwell Automation has extended its range of Safe-off drives by offering the DriveGuard safety system as an option on the PowerFlex 700S ac drive and extending it into high power capacity drive applications. Fully compliant with EN954-1 Category 3, the Safe-off feature of DriveGuard disables the motor and hence the driven machine's ability to move, until it is deemed safe to do so.
The DriveGuard option uses redundant signals to remove power from the output IGBT power transistors via a hardwired enable signal and a positive-guided relay, the latter also providing feedback to the safety system regarding the status of the drive. This replaces the traditional two-contactor safety system, with all its associated wiring, cost and complexity.