Top brand AC drives

This requirement could be needed for a multitude of reasons, but the most common ones include reprogramming or servicing of the AC drive, or in the rare event of the AC drive mechanically failing. In the early days of AC drives, back some 20 years ago, their failure rate was an issue. However, today it is rare for any AC drive to just mechanically fail. The requirement for a bypass is also critical in applications that demand essential services and smoke purge capabilities, where it is imperative that the motor runs to destruction if necessary.
An ac motor may act either as a motor that turns electrical power into mechanical power or as a generator that converts mechanical power into electricity. It depends on whether the motor is turning a machine that requires power to turn the machine or whether the load of the machine will at times overhaul the motor. (Overhauling is a condition where the mechanics or physics of the load mechanically cause the motor to attempt to turn faster than the motor speed the AC drive is commanding and the AC drive is used to slow down the motor speed.) This overhauling condition may exist in several types of applications.
The bypass enclosure itself is also used to house additional customer required components like line or load reactors and other devices for circuit protection. Line and load reactors are used for conditioning of the power. The other components facilitate the isolation and switching of the control devices.