A frequency inverter regulates the speed of a 3-phase AC electric motor by controlling the frequency and voltage of the power it delivers to the motor.A frequency inverter regulates the speed of a 3-phase AC electric motor by controlling the frequency and voltage of the power it delivers to the motor. Today, these devices are becoming prevalent in a wide range of applications throughout industry, from motion control applications to ventilation systems, from wastewater processing facilities to machining areas, and many others.
Inverter offer many benefits- principle among them the ability to save a substantial amount of energy during motor operation. In that sense, these devices represent both an attractive, “green” engineering solution, and an economical choice. Other benefits worth mentioning include the following: they can maintain torque at levels to match the needs of the load, improve process control, reduce mechanical stress on 3-phase induction motors by providing a “soft start,” and improve an electrical system’s power factor. What’s more, legacy systems that now use throttling devices to regulate motor speed can be retrofitted with frequency inverters to make speed regulation much more efficient and precise.
Special consideration must be given to the proper installation and operation of the overall system that comprises the frequency inverter, the motor it controls, and the cable that connects them.
For a schematic depicting a generalized frequency inverter system. The way in which frequency inverter-based systems are constructed and operated will have an impact on both the longevity and reliability of all the components of the system, as well as nearby or adjacent systems.
It is primarily concerned with the motor-supply cable in the frequency inverter/motor system. It looks at some fundamental cable design considerations, and presents suggestions for installation. However, to give the reader some context, it makes sense to first describe frequency inverters, their benefits and potential problems, and their relationship to the motors they control.