Frequency converter

Controlling the pump with frequency converters

A frequency converter is a power converter that generates an output current variable in frequency and voltage from an alternating current in one or more phases.

This converted output value is then used to drive and control a three-phase motor. The operating principle of the converter is that an incoming alternating quantity is first rectified in its respective phases using diodes and smoothing capacitors as an intermediate quantity and is then alternately rectified in a controllable manner using transistor or thyristor groups. The output frequency and the output voltage/current of the individual phases can be regulated by means of an integrated circuit control. The frequency converter for pump control can either be integrated in the pump or housed in control cabinets. According to the IP protection classes, the control cabinet for the control must provide protection against dust, water, overheating, and electromagnetic and mechanical interference.

Advantages of a control system with FI

Pump control systems come in many forms, but the option of using FIs or frequency converters is one of the most elegant ways of controlling pump motors. By controlling the frequency, the frequency converter can, for example, flexibly adjust the flow rate of circulating pumps to the actual demand requirements. This results in high potential savings in the energy consumption of the pump system. Pump control thus has the property of energy efficiency. Especially in the industrial sector with variable delivery volumes, high savings potentials can be achieved. Furthermore, many programs are available for pump control, which are gentle on the motors and thus minimize maintenance costs. Another advantage is the fast controllability of the pump system. The inverters in the pump control react in fractions of a second to changes in the sensors and can very quickly compensate for them and make adjustments.