Rockwell Automation Medium-Voltage Drive Reduces Downtime With Safe Torque Off

A new safe torque off option within the Allen-Bradley PowerFlex 7000 medium-voltage drive from Rockwell Automation helps industrial manufacturers and equipment builders simplify their functional safety design and meet the demands of international safety standards.

Safe torque off technology allows users to reliably remove power from the motor without removing power to the drive, enabling a faster re-start of the system after a safe state is reached. “Medium-voltage drives often run the most critical assets in an operation. Starting and stopping a drive repeatedly using input disconnect devices can create significant downtime and cause wear on these critical assets,” said Mark Banas, product manager, Rockwell Automation. “Medium-voltage-drive users can now help keep operations running and provide a safer work environment with certified safe torque off technology.”

When a safe torque off command is issued in the drive, from a user or a demand on the functional safety system, the PowerFlex 7000 drive immediately removes rotational power to the motor, ceasing the process. The drive stays powered and reliably monitors this “safe” state, ensuring no unintended operation of the motor is possible.   Rockwell Automation engineers designed the safe torque off option directly into the drive control, greatly simplifying setup and system design for functional safety. It works side by side with the drive’s control functions and does not require additional electromechanical components. This helps eliminate wiring needs, and lower users’ hardware inventory and installation costs.

Safety triggers – such as push buttons or light curtains – wire directly to the drive, removing the need for additional hardware. Ideal for industrial applications, such as material-handling conveyors and grinding mills, the PowerFlex 7000 drive with safe torque off is TÜV-certified. It is also certified to Safety Integrity Level (SIL) 3 of IEC 6150, and Performance Level e (PLe), Category 3 of ISO 13849-1, the highest levels achievable for drives.