Critical Load - Devices and equipment whose failure to operate satisfactorily jeopardizes the health or safety or personnel and/or results in loss of function, financial loss, or damage to property deemed critical by the user.
Load (linear) - Load for which voltage form and current form are similar. Voltage and current are related by Ohm's law U(t) = Z x I(t).
RS422A (Recommended standard RS422A) - Standard RS232C is sufficient for transmissions in a normal environment. For transmissions in a disturbed environment or over long distances, standard RS422A offers a differential operation option, with a balanced voltage, ensuring far superior performance. What is more, it can be used for multipoint links, with generally up to ten connection points (one sender and up to ten receivers).
Harmonics (current and voltage) - All alternating current which is not absolutely sinusoidal is made up of a fundamental and a certain number of current harmonics which are the cause of its deformation (distortion) when compared to the theoretical sine-wave. For each current harmonic of order n and an rms value In, there is a voltage harmonic with an rms value Un. If Zsn is the voltage source output impedance for the harmonic of the nth order, then - Un = Zsn x In
Fourier theorem - Theorem stating that any non-sinusoidal periodic function (frequency f) may be represented as a sum of terms (series) made up of - n a sinusoidal term with frequency f, called the fundamental frequency, n sinusoidal terms with frequencies that are whole multiples of the fundamental frequency, (harmonics), n a possible DC component where n is a whole number. n = 1 corresponds to the fundamental, n > 1 to the harmonic of the nth order.
Inverter (off-line or stand-by) - UPS configuration in which the inverter is parallel-mounted to the load supply line and backs up the mains. This configuration offers a substantial cost reduction but is applicable only to low outputs, under 3 kVA, because it results in an interruption lasting up to 10 ms during transfer and does not filter inrush currents.
Power Surge - Voltage above 110% of rated RMS voltage for one or more cycles.