Controlling the pump with a frequency inverter

A frequency converter is a power converter that generates an output current with variable frequency and voltage from single-phase or multi-phase alternating current.

This converted output value is then used to drive and control a three-phase motor. The functional principle of the inverter is that an incoming alternating variable is first rectified in its respective phases using diodes and smoothing capacitors to form an intermediate variable, which is then in turn 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 control unit. The frequency converter for regulating the pump control can either be integrated into the pump or housed in control cabinets. According to the IP protection classes, the control cabinet must offer protection against dust, water, overheating and electromagnetic and mechanical interference.

Advantages of a control system with FU

Pump controls are available in many designs, but the option of controlling pump motors using VFDs or frequency inverters is one of the most elegant types. By controlling the frequency, the FI can, for example, flexibly adapt the delivery rate of circulation pumps to the actual demand requirements. This results in high potential savings in the energy consumption of the pump system. The pump control therefore has the property of improving energy efficiency. Particularly in the industrial sector with variable delivery volumes, high savings can be achieved. Furthermore, many programs are available for controlling the pumps, which are gentle on the motors and thus minimize maintenance costs. Another plus point is the fast controllability of the pump system. The inverters in the pump control system react in fractions of a second to changes reported by the sensors and can adjust and correct them very quickly.