The prevalence of electronic variable speed drives in industrial electric motor applications has also seen an increase of motor cooling requirements.
Industrial electric motors that are TEFC (totally enclosed fan cooled) come standard as IC411, which features a cooling fan driven by the electric motor rotor. This cooling fan is efficient enough to allow S1 full-time operation for the motor, provided that the motor speed is sufficient.
As a general rule, with motor speeds below 15hz, the standard motor fan is not rotating fast enough to provide enough cooling. This is where a forced cooling (IC416) electric motor is utilised.
IC416 forced cooling allows an electric motor to be used at speeds below 15hz and in high ambient heat applications. The forced cooling is achieved by using an independent electric fan, attached where the original motor fan would go, and driven by its own electric motor. Depending on the frame size, this motor can be driven by either single phase or three phase power. By request when ordering, the fan can also be connected via the main motor terminal box.
Consider the Application
The best way to ensure that your motor / gearbox and VSD combination is suited to the application is to consider the full load and speed spectrum during the design stage. If the speed is going to be at the lower end of the motor range, a forced cooled motor does not add too much to the motor price overall and increases design flexibility.