USING A TANDEM DRIVE FOR CENTRIFUGAL FANS: A WAY TO LOWER INVESTMENT IN PETROCHEMICAL AND OIL & GAS FACILITIES

摘要

Manufacturers often invest in two parallel production lines to ensure there is no interruption of output when one line is being maintained or repaired. A tandem drive is a way to avoid that additional investment. A tandem drive for centrifugal fans comprises two drives: a medium- or high-voltage motor and a steam driven turbine. A medium- or high-voltage motor serves to start up the centrifugal fan, since steam from the boiler houses may not be available at the start-up of the plant. As soon as sufficient steam is on hand, the plant switches to the steam turbine. These drives can switch over automatically, without interrupting the production process from one drive to the other. Changing from the electric motor to the steam turbine calls for the steam turbine to be brought up to the rated speed of the motor through speed regulation. When a defined differential speed between the two drives has been reached, the turbine takes over and the electric motor can be switched off. The electric motor is removed from the shaft unit via an overrunning one-way clutch.