Which two statements are correct about a Rotary UPS?

The correct statement regarding a Rotary UPS is that it is one of the earliest UPS designs and has excellent fault clearing capability. Rotary Uninterruptible Power Supplies are designed to provide continuous power through a rotating mass, usually involving a flywheel and generator system. This design allows for a rapid response to power disturbances and the ability to ride through brief outages, effectively clearing faults in the electrical system.

This technology's reliability is one of its main advantages, particularly in large-scale applications where power quality and availability are critical. The rotating inertia of the flywheel helps to stabilize the voltage and reduce the risk of electrical fluctuations, providing a dependable power source.

In contrast, other statements do not accurately describe the Rotary UPS. For example, these systems are not typically connected directly to personal computers; they are usually employed in commercial and industrial settings. Additionally, Rotary UPS systems have moving parts, which is contrary to the claim about having no moving parts. Finally, they do not operate solely as battery backups; rather, they provide continuous power and can handle varying loads with their flywheel systems.