Load (non-linear) - Load (generally with a switched-mode power supply) generating major harmonic currents. Current wave form is different from voltage wave form. Ohm's law is not applicable. It can be used only with each harmonic.
Rectifier/charger - UPS component that draws on the mains the power required to supply the inverter and to float charge or recharge the battery. The alternating input current is rectified and then distributed to the inverter and the battery.
Power source (safety) - Power source for loads defined as critical by applicable safety regulations. This supply must not be affected by a mains failure and is generally separate from other supplies.
Bypass (manual) - Manually-operated switch used to supply the load via direct connection to utility power during servicing of the UPS system.
Reversal - The changing of the normal polarity of a battery due to overdischarge.
Interference (high-frequency) - High-frequency parasitic current that is either conducted (electrostatic origin) or radiated (electromagnetic origin) by a device.
Frequency Variation - A change in frequency of more than 3 Hz.