These motors are created for the application form Variable Drive Motor requirements of variable rate drive systems. We offer both the following types of motors:

• Constant Torque: Motors specifically designed to handle constant torque loads, such as conveyors, positive displacement pumps, cranes, etc.
• Variable Torque: Motors specifically designed to handle adjustable torque loads such as for example pumps and fans.
Due to fast 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 effect 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 break down, resulting in feasible sparking. ABB recommends:

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

Automatic frequency control contain an primary electric circuit converting the alternating current into a direct current, then converting it back into an alternating current with the required frequency. Internal energy loss in the automatic frequency control is ranked ~3.5%
Variable-frequency drives are widely used on pumps and machine device drives, compressors and in ventilations systems for huge buildings. Variable-frequency motors on fans save energy by permitting the volume of atmosphere moved to match the system demand.
Reasons for employing automated frequency control can both be linked to the efficiency of the application and for conserving energy. For example, automatic frequency control is used in pump applications where the flow is matched either to quantity or pressure. The pump adjusts its revolutions to a given setpoint via a regulating loop. Adjusting the movement or pressure to the actual demand reduces power intake.
An AC motor speed control-also known as a variable frequency drive, adjustable frequency drive, variable rate drive, adjustable swiftness drive and AC inverter-is an electro-mechanical object that can be used to change the output acceleration of an AC engine by adjusting the input frequency into the motor.