This once was the dominant form of UPS and is also restricted to around the a hundred and fifty kVA variety. These units are still primarily applied in certain industrial settings (oil and fuel, petrochemical, chemical, utility, and weighty industry marketplaces) due to the robust nature of the UPS. At https://lukaszdamj.jiliblog.com/90565583/5-simple-statements-about-uninterruptible-power-supply-calculator-explained