The 1PH8 range of motors for main drives developed by the Drive Technologies Division of Siemens, Nuremberg, now has models equipped with energy-efficient, electronically commutated, force-ventilated fans.
The fans cool the motors with rated outputs up to 310 kW. The coolers typically are deployed in the medium-to-high power range and comply with IE3, the premium energy-efficiency class.
Like water cooling, forced ventilation is a method of cooling to extract motor heat losses, which enables the machine to produce high load torques at low speeds. The variant with external air supply can cool the motor even when it is at standstill. According to Siemens, the fans operate at the optimum point no matter what the connected voltage and frequency are. In addition, says the manufacturer, with efficiency factors in excess of 90 percent, they consume little energy.