Var (unit)

Physical unit
Unit name	Var
Unit symbol	${\displaystyle \mathrm {var} }$
Physical quantity (s)	Reactive power
Formula symbol	${\displaystyle Q}$
dimension	${\displaystyle {\mathsf {M\;L^{2}\;T^{-3}}}}$
In SI units	${\displaystyle \mathrm {1\,var=1\;W=1\;V\cdot 1\;A} }$
Named after	French Volt-Ampère-réactif
Derived from	Volts , amps
See also: watts , volt-amps

The var (with the unit symbol : var) is a legal unit for reactive power in electrical power engineering . The Var was formerly also called Blindwatt (unit symbol: bW).

origin

The name Var comes from the term “ V olt a mpere R eaktiv” and was proposed in 1932 by the Romanian Constantin Budeanu and established by the International Electrotechnical Commission (IEC). Before that, the VDE committee for units and formulas (AEF) dealt on March 22, 1921 with a draft on the designation of alternating current quantities. It was suggested to name the unit of reactive power with the designation Dol , named after Michail Ossipowitsch Doliwo-Dobrowolski . In the end, this designation could not establish itself at the IEC.

Similar performance units

According to the International System of Units , the watt is defined as the unit of power . According to the German Unit Ordinance and DIN 1301 Part 1, the Var can be used as a special unit for the electrical reactive power, the VA for the apparent power ; the watt is then only used for the active power .

Individual evidence

1. ^ Romanian NC celebrates 80 years of world-class standardization ( Memento of October 4, 2013 in the Internet Archive )
2. ↑ Short biography of Constantin Budeanu on the IEC webpage (in xml) , (September 4, 2011)
3. ^ Gerhard Neidhöfer: Michael von Dolivo-Dobrowolsky and the three-phase current . 2nd Edition. VDE-Verlag, 2008, ISBN 978-3-8007-3115-2 , p. 227 .
4. ↑ Implementing ordinance to the law on units in metrology and time determination , (September 4, 2011)
5. ↑ DIN 1301: 2010-10 units - Part 1: Unit names, unit symbols ( Memento from February 23, 2015 in the Internet Archive )