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Off-line UPS A UPS type which feeds power to the load directly from the utility and then transfers to battery power via an inverter after utility drops below a specified voltage. The delay between utility power loss and inverter startup can be long enough to disrupt the operation of some sensitive loads. Also called a standby UPS.

Online UPS A UPS in which the inverter is on during normal operating conditions supplying conditioned power to the load through an inverter or converter that constantly controls the AC output of the UPS regardless of the utility line input. In the event of a utility power failure, there is no delay or transfer time to backup power.

Outlet Any point on a wiring system where current is taken to supply electrical power for a load.

Output Enable Delay The delay between the start of primary side switching and the start of output current walk in. This is in two parts: a fixed hardware delay controlled by the secondary side control circuits and an adjustable delay controlled by the microprocessor. During this period the output voltage is at the minimum of approximately 40 V.

Overload A condition in which the load wants more from the power source (such as a UPS) than the power source has been designed to supply.

Over-voltage Shutdown (OVSD) A protection method that will shutdown any rectifier module with an output voltage over a preset maximum value.