This rating reflects the amount of current the switch contacts can handle at the moment the device is turned on. Switches that are going to be subjected to high-inrush inductive loads, such as an AC motor, will often be rated in horsepower in addition to volts and amps. So, in the example below the maximum amp rating for this switch at 250 volts AC (VAC) is 10 amps the maximum amp rating at 125 volts AC for the same switch is 15 amps. The amp rating of a Carling switch is the maximum current in amperes the switch will carry continuously. The voltage rating specified on Carling Technologies' switches represents the maximum voltage allowable for the switch to function properly at the rated current. The voltage rating is a function of a switch's ability to suppress the internal arc that occurs when a switch's contacts open. One horsepower (1HP) is also equal to 746 watts of electrical power.
Motors are rated in horsepower (HP) or fractions of horsepower (1/4, 1/3, 1/2, etc.) Mechanically, one horsepower (1HP) is equal to 33,000 pounds being moved 1 foot in 1 minute (or 33,000ft-lb/min). Voltage is also called electrical potential, because if voltage is present in a conductor, there is potential for current flow. Voltage itself does not flow through conductors, but is the force that causes current to flow. The electrical pressure necessary to cause this movement is voltage. The flow of electrons through an electrical conductor is called electrical current, which is measured in amperes or amps. Carling Technologies switch ratings are listed by amperes, volts, and horsepower (when applicable).Įlectricity is the movement of electrons from one atom to another. The difference in those numbers arises from the fact that a lightning strike only lasts a matter of a few tens of milliseconds (thousandths of a second).Any Carling Technologies' switch that has agency approvals will have its ratings stamped on its base. That’s why an average lightning bolt carries around 5 coulombs of charge, even though its current may be tens of thousands of amps.
One ampere is the current in which one coulomb of charge travels across a given point in 1 second. One coulomb is equal to about 6.241 x 10 18 electric charges ( e).
But the quantity of electric charge by itself, whether in motion or not, is expressed by another SI unit, the coulomb (C). The ampere is a measure of the amount of electric charge in motion per unit time ― that is, electric current. Starting on May 20, 2019, the ampere is based on a fundamental physical constant: the elementary charge (e), which is the amount of electric charge in a single electron (negative) or proton (positive). In November 2018, however, the redefinition of the ampere ― along with three other SI base units: the kilogram (mass), kelvin (temperature) and mole (amount of substance) ― was approved. Its mass value drifted over time and thus limited the accuracy of its derived units. m/s 2) was derived from the SI unit of mass: the kilogram stored in Sèvres, France.Equally unsatisfactory was the fact that the amp, though an electrical quantity, was defined in mechanical terms. The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 meter apart in vacuum, would produce between these conductors a force equal to 2 x 10 -7 newton per meter of length.īecause infinitely long wires and vacuum chambers were generally unavailable, the ampere could not be physically realized according to its own definition, though it could, with considerable difficulty, be approximated in a laboratory. Until 2019, its official definition ― a general version of an experiment conducted by French scientist André-Marie Ampère in the 1820s ― specified a completely hypothetical situation: The ampere has been an internationally recognized unit since 1908, and has been measured with progressively better accuracy over time, most recently to a few parts in ten million.īut defining the ampere has been problematic at best. LEDs are very energy efficient currents for a small LED can be just a few thousandths of an amp. A 468-pixel cryogenic LED mapper for superconducting photon detectors.
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