Thermostat - A temperature sensitive switch.
Cubicle (single UPS unit) - Cubicle containing a rectifier/charger, an inverter and a bypass. Connected to a battery, it operates alone, forming a single UPS. Compare with Cubicle (parallel UPS unit).
Primary Battery - A battery which is not intended to be recharged and is discarded when the battery has delivered all of its electrical energy.
Earthing system TT - Earthing system in which the neutral and the exposed conductive parts are directly earthed. The installation must be de-energized immediately in the event of an insulation fault.
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.
Static bypass switch - Power-electronics device that can be used to switch from one source to another without interruption in the supply of power. In a UPS, transfer is from Mains 1 to Mains 2 and back. Transfer without interruption is possible due to the fact that there are no mechanical parts and the ultra-fast switching capabilities of the electronic components.
Forced Discharge - Discharging a cell in a battery, by the other cells or an external power source, below zero volts into voltage reversal.