Brownout - A steady state RMS voltage under nominal by relatively constant percentage.
Harmonic Sinusoidal - Term of the Fourier series expansion of a periodic function. The harmonic (or harmonic component) of the nth order is characterized by - Yn is the rms value of the given harmonic component, w is the angular frequency of the fundamental, related to frequency by - w = 2_f; phin is the phase angle of the given harmonic component at t = 0.
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.
Earthing system IT - Earthing system in which the neutral is isolated from the earth or connected to the earth via a high impedance and the various exposed conductive parts are connected to the earth via individual earthing circuits. An alarm must signal the appearance of a first insulation fault. The installation must be de-energized immediately in the event of a second insulation fault.
Closed-Circuit Voltage (CCV) - The potential or voltage of a battery when it is discharging or charging.
Voltage Depression - An abnormal drop in voltage below expected values during the discharge of a battery.
