Automation control systems based on variable frequency drives technology.

Having already, quite long history and rapidly growing applications with variable frequency drives require very good understanding of process technology and electrical power supply standards. Otherwise, potentially good solution may cause dramatic consequences.

Engineering Center ART has collected interesting cases and expertise from more than 400 completed projects with VFD control technology. Most of our projects are based on modular design allowing our customers constantly upgrade their facilities with more and more effective solutions. This concept has many times proven its ability to save Customer cost regarding Russian business practice and economy situation.

Low voltage frequency drives and control systems

Our most frequent projects that already become standard solutions include low voltage VFD that uses built in PLC to control different fans or pumps in one technology cycle. For Vacon NX series drives, we have developed different applications for net pumps, feed pumps, wastewater pumps, compressors, fans. In each case, we can provide the application that could secure the system from water-hammer effect, cavitation problems and valves critical angles. Of course, our customers benefit from savings of electrical power that may reach up to 60% from nominal drive capacity.

Liquid cooled VFD systems

For applications with limited space, high temperature or explosive atmosphere we suggest to use liquid cooled frequency inverters. Engineering Center ART design and produce the VFD system and inverter water cooling station. One station may supply cooling water to several inverters. The circulation of water may be open type and closed type.

Medium voltage frequency drives and systems

The bigger capacity pump or fan are controlled by VFD the bigger amount of electric power customer can save. From 400 kW up and to 8 MW we apply 6 kV or 10 kV medium voltage frequency drives. One proven solution is to use "real" MV VFD based on multilevel power cells structure. Hyundai Heavy Industries produces such systems using standard Semicron power cells. We regards those N5000 series frequency drives as flexible, reliable and cost saving solution. One of our example projects includes N5000 630 kW 6 kV.

In some cases, our customers prefer to apply the proven solution with "step down step up" transformers. It makes possible to place the equipment in very narrow space especially with liquid cooled VFDs. In such solutions, we also rely on long years' experience of Vacon and special transformers produced by Trafeco.

Very good feature of VFD is that it can start the motor with current level that does not exceed nominal. Motor does not overheat and obtains longer lifetime and bigger number of possible starts.

VFD systems for synchronous motors

Synchronous motors are usually have better efficiency and power factor comparing to induction motors. Installation of VFD control with synchronous motor requires certain adjustment of excitation system or even installation of new one.

Special control algorithm allows synchronous motor transfer to power grid when it reaches nominal speed (grid frequency). This allows as using one MV VFD unit for soft start function of many motors and control function of one motor. That method is called cascade regulation.

For each project, we design electrical panels for motor control and control panels with PLCs, HMIs, and UPS.

Electrical panels are low and medium voltage for overall bus currents up to 5000 A. This equipment we usually order from leading panel maker companies in Saint Petersburg.