Glossary: A

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Absorber – Solar Photovoltaic Industry

The absorber is that part of a solar thermal collector that receives the incident radiant energy and transforms it into heat energy.

AC

Alternating Current electrical power supplied by a utility company or from an AC generator.

AC Distribution

A module in the power system that distributes AC power to other power system modules.

AC Metering

Measurement of AC power input voltage and current parameters by sampling. The results of the measurements are used to calculate the rms (Route Mean Squared) equivalents for voltage, current and power, and also calculate the power factor and frequency.

AC Utility

The electric power furnished by an electric power utility company.

Active Load Share

A current sharing scheme controlled by the supervisory module that adjusts the output voltage of individual rectifiers so that all rectifiers in a DC power system produce the same output current.

Active Solar Thermal System – Solar Photovoltaic Industry

A system that traps the sun's energy with solar collectors and uses an electromechanical subsystem to move that energy to its point of intended use for water heating, space heating, pool heating, industrial process heat, electrical generation and space cooling.

Active Voltage Control

The supervisory module adjusts the rectifier output voltages to maintain a constant DC power system voltage (measured at the output or battery) independent of load fluctuations during normal operation.

Advanced Battery Management

A three-stage charging system designed to prolong the service life of UPS batteries. By charging the batteries only when necessary, battery life is significantly improved. Charging stage one: quickly recharges battery to approximately 90% of capacity. Charging stage two: fully charges the battery to 100%. Charging stage three: rest mode prevents overcharging. Charging stage one is initiated after a power outage or periodic UPS self-test.

Agent

A software program that acts as a focal point for data collection and configuration of a specific network entity (hardware or software). SNMP agents provide data to management stations regarding the operation and configuration of devices on a network.

Alternating Current

Current which changes (or alternates) direction at regular intervals. Since the current flows in one direction for the same amount of time that it flows in the opposite direction, the average value of the current flow is zero.

Alternating Current (AC) – Solar Photovoltaic Industry

An electrical current in which the direction of electron flow reverses periodically, usually many times per second. Most U.S. household electrical systems use AC current rated at 120 volts and 60 cycles per second.

Alternator – Solar Photovoltaic Industry

An mechanical device that generates alternating current electricity.

Altitude Angle – Solar Photovoltaic Industry

The angle of the sun above the horizon, measured in degrees. In winter, the sun is at a low solar altitude, and in the summer, the sun is at a high solar altitude.

Ammeter – Solar Photovoltaic Industry

A device used for measuring the current (amperage) at any point in an electrical circuit.

Amorphous Silicon – Solar Photovoltaic Industry

A thin-film PV silicon cell having no crystalline structure.

Amp

The unit of measure for current. One ampere is the amount of electricity per second that flows through a conductor such as a wire.

Ampacity

Ampacity is defined as the maximum amount of electrical current a conductor or device can carry before sustaining immediate or progressive deterioration. Also described as current rating or current-carrying capacity, Ampacity is the RMS electric current which a device or conductor can continuously carry while remaining within its temperature rating.

Ampere

The unit of measure for current. One ampere is the amount of electricity per second that flows through a conductor such as a wire.

Ampere (Amp or A)

A unit of electrical current or rate of flow of electrons. One volt across one ohm of resistance causes a current flow of one ampere. One ampere is equal to 6.235 x 10 18 electrons per second passing a given point in a circuit.

Ampere (Amp; A, I) – Solar Photovoltaic Industry

The rate of flow of electrical charge. Unit of electrical current. One volt across one ohm of resistance causes a current of one ampere. One ampere is equal to 6.235 x 10^18 electrons (one coulomb) per second passing a given point in a circuit.

Ampere-Hour (amp-hour; Ah) – Solar Photovoltaic Industry

A measure of current over time, used to measure battery capacity and state of charge. For example, a current of 1 amp drawn from a battery for 10 hours would result in 10 amp-hours of charge cycling through the battery.

Ampere-Hour Meter – Solar Photovoltaic Industry

An instrument that monitors electron flow over time. Amp-hours are the product of electron flow (in amperes) and time (in hours).

Amplitude

Generally refers to the maximum and minimum voltage attained by an alternating or pulsed current in each complete cycle or pulse of that current.

Angle Of Incidence

The angle between the sun’s rays and a line perpendicular to the active surface of a solar module or collector, in degrees.

Angle Of Inclination

The angle that a solar collector or PV module is positioned above horizontal.

Anode

( Battery ) The electrode within a battery cell that undergoes the chemical process of oxidation. Electrically, the anode is the cell's positive terminal. (Water heater) An aluminum or magnesium sacrificial rod installed within steel tanks that is used to help prevent corrosion of the tank itself.

Array

Any number of photovoltaic modules connected together electrically to provide a single electrical output.

AVC

Active Voltage Control: The supervisory module adjusts the rectifier output voltages to maintain a constant DC power system voltage (measured at the output or battery) independent of load fluctuations during normal operation.

Awg

American Wire Gauge, a set of standards in the U.S. specifying the diameter of wire. A higher number indicates smaller wire.

Azimuth

The angle between true south and a point on the horizon, measured in degrees east or west of true south.