Definitions for volt-ampere
This page provides all possible meanings and translations of the word volt-ampere
Random House Webster's College Dictionary
an electric measurement unit, equal to the product of one volt and one ampere, equivalent to one watt for direct current systems and a unit of apparent power for alternating current systems.
Category: Electricity and Magnetism
Ref: Abbr.: VA 1
Origin of volt-ampere:
a unit of electrical power in an AC circuit equal to the power dissipated when 1 volt produces a current of 1 ampere
A volt-ampere is the unit used for the apparent power in an electrical circuit, equal to the product of root-mean-square voltage and RMS current. In direct current circuits, this product is equal to the real power in watts. Volt-amperes are useful only in the context of alternating current circuits. While both the volt-ampere and the watt have the dimension of power, they do not have the same meaning. Some devices, including Uninterruptible Power Supplies, have ratings both for maximum volt-amperes and maximum watts. The VA rating is limited by the maximum permissible current, and the watt rating by the power-handling capacity of the device. When a UPS powers equipment which presents a reactive load with a low power factor, neither limit may safely be exceeded. For example, a UPS system rated to deliver 400,000 volt-amperes at 220 volts can deliver a current of 1818 amperes.
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