Alternating current. An electric current that flows back and forth, typically changing direction 50 or 60 times per second.
Ampere. The standard unit for measuring the strength of an electric current.
Ribbon-shaped wires that show promise as a next generation wire technology. These wires are made by depositing thin films of intermediate materials, e.g. cubic zirconia, on ribbons of metals, followed by deposition of a thin layer of HTS material and a protective coating.
A wound spiral of wire that forms an electromagnet when energized. Specific coils are often named for their particular geometric design. For example, a "racetrack" coil is oval shaped.
The branch of engineering that pertains to materials and equipment that are used at very low temperatures.
Conductors that carry large amounts of power but minimal heat into ultra-low temperature cryogenic environments. Current leads address the critical problem of heat leak.
A device used to instantaneously limit the flow of excessive electrical current (fault current) in a circuit, thereby protecting expensive electrical equipment. Fault currents are typically caused by short circuits, lightning or common power fluctuations.
An insulating substance such as oil, liquid nitrogen or paper.
Fluctuations in the voltage or current on a power system that can affect the performance and operation of electrical equipment.
Equipment that converts electrical energy into useful mechanical power.
Electric and magnetic fields surrounding any wire that conducts electricity.
Reserving electric energy for later use to avoid blackouts or fluctuations in power. Storage methods include batteries, flywheels, pumped hydropower and Superconducting Magnetic Energy Storage (SMES).
Electric Power Research Institute. Founded in 1972, EPRI identifies and pursues advanced technology for the U.S. electric utility industry to improve power production, distribution and use. EPRI serves approximately 700 member utilities.
The momentary flow of excessive electrical current in a circuit. It is usually caused by short circuits, lightning or common power fluctuations.
Equipment that converts rotational mechanical input power, such as that from a steam turbine, into electricity by using electromagnetic force.
The electric power industry infrastructure of interconnected electrical systems and services that provide power to all users.
High Temperature Superconductor (HTS)
Resistance-free conductors made of ceramic materials that exhibit superconducting properties at temperatures between 20 to 130 Kelvin (-423° to -225°F), therefore requiring less expensive cooling systems than those needed for low temperature superconductors (<10 Kelvin, -441° F). The first high temperature superconductor was discovered in 1986.
Horsepower. A measurement of power used to rate motors. HTS technology will be most effective at first in motors rated 1,000 hp and higher.
A device that stores electrical energy in a magnetic field.
A type of power converter that converts dc power into ac power.
Ion-Beam Steering Magnets
Devices used for guiding particle beams in systems such as particle accelerators for physics research or ion-implantation equipment for semiconductor manufacturing.
A unit of measurement of energy equal to a watt-second. kJ represents a kilojoule (1,000 joules); MJ is a megajoule (one million joules).
Kilovolt-amperes. A unit of measure of apparent power.
Kilowatt. A unit of power equal to 1,000 watts or about 1.34 horsepower.
An inexpensive, inert and non-toxic liquid cryogen formed by chilling gaseous nitrogen to 77 Kelvin (-320° F). Liquid nitrogen is used to cool HTS wires and components to achieve superconducting performance in applications such as power cables and transformers.
Low Temperature Superconductivity
Megavolt amperes. A unit of measure of apparent power.
HTS materials are compounds of metals with oxygen. A metallic precursor is an alloy of the metallic components that is formed into a desired wire shape and then reacted with oxygen to create the HTS compound.
Devices that are used for converting power from dc to ac or vice versa. They are used in motor controllers, chemical processing, energy storage and large industrial processes.
A smooth, even flow of electricity – free of variations in voltage, current or frequency that provides a competitive advantage for utilities and their industrial customers.
Solid-state devices, such as transistors, used for the conversion and control of electric power.
An obstruction to the free flow of electrons in a material. Resistance causes electric current to lose energy in the form of heat.
Superconducting magnetic energy storage. Devices based on the principle that an electric current introduced into a resistance-free superconducting coil lasts indefinitely and never dissipates energy – which provides a backup power supply that's always charged and ready to respond instantly to power fluctuations.
A unit of measure of magnetic field strength. For example, an ordinary kitchen magnet has a magnetic field strength of less than 0.05 Tesla. American Superconductor has produced magnet coils surpassing 2 Tesla, the threshold rating for commercial HTS motors and generators.
A device that converts power from one voltage and current level to another. Transmitting energy at higher voltages is more efficient, but consumers need low voltage power. Electricity experiences several voltage changes enroute to an end-user.