Frequency - The repetition of cycles measured in Hz. 60 Hz is the standard frequency in the U.S. 50 Hz is the standard frequency in other parts of the world. 60 Hz = 60 cycles per second.
Electrochemical Equivalent - Weight of a substance that is deposited at an electrode when the quantity of electricity which is passed is one coulomb.
Positive Temperature Coefficient (PTC) - A thermally reactive device which becomes highly resistive at a specific temperature or current.
Transformer short-circuit voltage (Uscx %) - Relative measurement (%) of the internal impedance of a transformer. This short-circuit impedance is commonly called the short-circuit voltage because it is measured during a short-circuit test (shorted secondary winding subjected to a current set to In). For most common three-phase transformers, this value ranges between 3 and 6%.
Constant Resistance Discharge - A battery discharge regime whereby the resistance of the equipment load remains constant throughout discharge.
Secure Waste Landfill - A landfill designed for disposal of normal household trash but which meets government standards designed to protect the environment.
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.