Henry (unit) Henry (unit) The henry (symbol: H) is the SI derived unit of electrical inductance. If a current of 1 ampere flowing through the coil produces flux linkage of 1 weber turn, the coil has a self inductance of 1 henry.‌ The unit is named after Joseph Henry (1797–1878), the American scientist who discovered electromagnetic induction independently of and at about the same time as Michael Faraday (1791–1867) in England. The inductance of an electric circuit is one henry when an electric current that is changing at one ampere per second results in an electromotive force of one volt across the
Copper loss also referred to as "I squared R losses", in reference to Joule's First Law. This states that the energy lost each second, or power, increases as the square of the current through the windings and in proportion to the electrical resistance of the conductors. where I is the current flowing in the conductor and R the resistance of the conductor. With I in amperes and R in ohms, the calculated power loss is given in watts. Joule heating has a coefficient of performance of 1.0, meaning that every 1 watt of electrical power is converted to 1 Joule of heat.