DUPS are sometimes combined or integrated with a diesel generator that is turned on after a brief delay, forming a diesel rotary uninterruptible power supply (DRUPS).Ī fuel cell UPS was developed by the company Hydrogenics using hydrogen and a fuel cell as a power source, potentially providing long run times in a small space. When the mains power fails, an eddy-current regulation maintains the power on the load as long as the flywheel's energy is not exhausted. A synchronous motor/alternator is connected on the mains via a choke.
Most UPS below one kilo volt-ampere (1 kVA) are of the line-interactive or standby variety which are usually less expensive.įor large power units, dynamic uninterruptible power supplies (DUPS) are sometimes used.
However, most UPS units are also capable in varying degrees of correcting common utility power problems: The primary role of any UPS is to provide short-term power when the input power source fails.
A UPS differs from an auxiliary or emergency power system or standby generator in that it will provide near-instantaneous protection from input power interruptions, by supplying energy stored in batteries, supercapacitors, or flywheels. A large data-center-scale UPS being installed by electriciansĪn uninterruptible power supply or uninterruptible power source ( UPS) is an electrical apparatus that provides emergency power to a load when the input power source or mains power fails.