Improved power quality

Almost sinusoidal input current eliminates the need for additional harmonic filters or active filters on the input side
∙ Compatible with older design of motors allowing retrofit to existing system designs.
∙ Minimal impact of voltage reflection, allowing longer cable length between motor and drive.
∙ Multi-level medium voltage drives minimise stress on motor windings, eliminating the need for additional sine
wave filters

 Energy saving

Fans, pumps and compressors have load characteristics whereby the power consumed increases as a cubic law with
speed.

The optimum way to save energy with this type of load is to control the motor speed with a VFD. This is far more effective as it avoids the waste of energy when fluid flow rate is controlled using a valve or damper.Process control is improved by the use of more accurate, prompt and flexible control of the motor speed.

The inherent soft starting ability of a VFD reduces the impact on the network (voltage dips) caused by high starting currents.

Substantially greater starting torques can be achieved with a VFD than with a soft starter and with much lower starting current, reducing stress on the motor windings and saving energy.The controlled start-up acceleration rate also reduces themechanical stress on the load equipment.

∙ The VFD operates at a higher input power factor than a directly connected asynchronous motor.

∙ The losses in the VFD converter are low, only 1.5% excluding the transformer.