The first placement of Caterpillar’s 250 kVA Uninterruptible Power Supply (UPS) system at a plastic extrusion plant in Charlotte, N.C., was tested almost immediately by two interruptions in the space of 17 days when one of the company’s four production lines lost power. Usually this results in hours of downtime because even a brief interruption or sag disrupts the entire extrusion process . Fortunately the electrical flywheel did its job on both occasions and Shaw Industries, who are reputedly the world’s largest carpet manufacturer, was impressed enough to consider installing UPS’s on its other three lines. At maximum kVA load, the flywheel will provide power for 10 to 15 seconds, allowing time for the standby plant to assume the load.
