UPS 120, UPS 150, UPS 250 and UPS 300 Uninterruptible Power Supplies Caterpillar

The Uninterruptible Power Supply (UPS) is a fully integrated line-interactive system that uses a flywheel to store mechanical energy as a rotating mass. When utility power is interrupted, the UPS converts mechanical energy stored in the flywheel to electrical energy. The energy is supplied to the external load until one of the following conditions occur:

• The standby generator assumes the load

• The utility power is available again

• The flywheel runs out of energy

Once utility power returns, the system transfers the load back to utility power without interruption. The UPS can be used in a wide range of commercial power applications. The systems provide voltage regulation and protection from power outages. The UPS is designed to provide well-regulated power for critical loads, sags, surges, or outages.

Illustration 1	g02808036
Simplified system diagram

The system contains the following components.

Input Contactor - A mechanical contactor controlling electrical flow into the UPS.

Output Contactor - A mechanical contactor controlling electrical flow from the UPS.

Bypass Contactor - An electrically operated contactor used to bypass the system.

Static Switch - The static switch is a thyristor device. The static switch isolates the UPS from the utility grid when an out-of-tolerance condition occurs.

Flywheel Converter - The flywheel converter is a semiconductor device that is used to convert the voltage from the DC bus into AC signals. When the power from the utility is not available, the flywheel converter will rectify AC signals from the flywheel to the DC bus.

Utility Converter - The utility converter is a semiconductor device used to rectify AC voltage on the filter node into DC voltage. When utility power is lost, the utility converter converts the voltage from the DC bus to the system operating voltage and frequency.