These motors are designed for the application form requirements of variable speed drive systems. You can expect both the following types of motors:

• Constant Torque: Motors particularly designed to handle constant torque loads, such as conveyors, positive displacement pumps, cranes, etc.
• Variable Torque: Motors particularly designed to handle adjustable torque loads such as pumps and fans.
Due to quick switching and reflections in the cables, motors are subject to more voltage stress in the windings when fed by frequency converters than with sinusoidal supply voltage. The result of these voltages can be an increase of up to 2.5 times the motor’s nominal voltage. This stresses the motor winding insulation and may cause it to breakdown, resulting in feasible sparking. ABB recommends:

Between 500 V or more to 600 V, the motor will need reinforced winding insulation, or the drive will need to have a du/dt filter.
Above 600 V, the motor will need reinforced winding insulation and the drive must have a du/dt filter.
If the cable duration between the drive and motor is greater than 150 meters and the voltage is between 600 and 690 V, the engine will need to have reinforced winding insulation.
A variable-frequency drive is something for controlling the rotational velocity of an alternating current electric engine. It handles the frequency of the electrical energy supplied to the motor. A variable frequency drive is a specific type of adjustable-acceleration drive. Variable-frequency drives are also called adjustable-frequency drives (AFD), variable-rate drives (VSD), AC drives, or inverter drives.

Automatic frequency control contain an primary electric circuit converting the alternating electric current into a immediate current, then converting it back into an alternating electric current with the mandatory frequency. Internal energy reduction in the automatic frequency control is rated ~3.5%
Variable-frequency drives are trusted on pumps and machine device drives, compressors and in ventilations systems for large buildings. Variable-frequency motors on supporters save energy by enabling the volume of air moved to complement the system demand.
Reasons for employing automatic frequency control may both be linked to the features of the application form and for saving energy. For example, automatic frequency control is utilized in pump applications where in fact the flow is usually matched either to volume or pressure. The pump adjusts its Variable Drive Motor revolutions to confirmed setpoint with a regulating loop. Adjusting the movement or pressure to the actual demand reduces power intake.
An AC motor velocity control-also known as a adjustable frequency drive, adjustable frequency drive, variable rate drive, adjustable acceleration drive and AC inverter-is an electro-mechanical object that can be utilized to change the output acceleration of an AC electric motor by adjusting the insight frequency into the motor.