Glossary

ABB Drive Assistant For ABB Drives, particularly the ACS355 Series, the Drive Assistant provides a convenient method to program and control the ABB Drive and electric motors. There are two version, the Basic with a one-line display and the Advanced with a three line display. Amortisseur Winding. In an AC …

Bonding. The act of interconnecting two or more conductive bodies to establish electrical continuity and conductivity. Baseline Speed. Listed on the nameplate of a given electric motor, the baseline speed is the full-load or running speed or rpm of the motor when it is operated at its rated voltage, rated …

Capacitance / Stray Capacitance. Capacitance is the storage of electricity in a capacitor. Capacitance in the earth is referred to as stray capacitance. Stray capacitance describes the storage of an electrical charge on the ground due to a natural difference of pressure (static electricity). Capacitor / Condenser. The descriptive term …

Demarcation Point. The term demarcation means the setting or marking of boundaries or limits. Demarcation point is the service point where the electrical-utility power transmission/distribution grid with installation governed by the NESC (National Electrical Safety Code) stops, and the electrical power distribution system for a building or other structure (premise …

Eddy Currents. Circulating currents induced in conductive materials by any type of varying electromagnetic fields. Effective Ground-Fault Current Path. An intentionally constructed, low-impedance electrically conductive path designed and intended to carry current under ground-fault conditions from the point of a ground fault on a wiring system to the electrical supply …

Footing. As used in a building or other structure construction: A structural unit used to distribute loads of the bearing materials. Free Electrons / Valence Electrons. The electrons located in the outer orbit of an atom. Normally associated with metals or other conductive material, free electrons are loosely held within …

Greenfield. The trade name for flexible metallic conduit. Ground Fault / Ground-Fault Overcurrent. (1) An abnormal connection in an electrical circuit, where the normal load path is either partially or completely bypassed through this non-circuit return path, which is the equipment-grounding system of an electrical power distribution system. The low …

High Voltage (High Tension). A general term used to describe circuits with system voltages greater than 600 volts and to imply that the voltage is of such a value that it is dangerous to humans. Extreme caution should always be used when troubleshooting equipment marked with this term. Horsepower (HP) …

I/O Module Field replaceable modules that accept or send signals from field devices and condition the signal for the CPU. IGBT Insulated Gate Bipolar Junction Transistor – A semiconductor device that provides the base technology for the modern drive. Imperial Units These are the measurement units used in the United …

Kirchhoff’s Current Law.   The sum of the currents entering and leaving a node is equal to zero; the sum of the currents entering a node is equal to the sum of the currents leaving that node. Kirchhoff’s Voltage Law.   The sum of the voltage drops in a closed loop …

Linear Load. A utilization-equipment load where the wave shape of the current follows — is in phase with — the wave shape of the applied voltage. At the point of common-return on the neutral conductor, linear single-phase AC currents cancel only the unbalanced load current. Line Disturbances. These are fluctuations …

Megger. An electrical test instrument that uses a high-voltage output for insulation testing and high-resistance measurements. Motor Starter A device used to supply full line voltage to a motor and include overcurrent protection. Motor Nameplate Every electric motor is labeled with a motor nameplate. The motor nameplate contains information about …

NEMA National Electrical Manufacturers Association is a group who publishes electrical and medical imaging standards.   No-Load Condition. An electric motor operating at rated frequency (AC) and rated voltage with the drive train of its mechanical load disconnected from the rotor driveshaft. The motor turns at near synchronous speed, which …

Ohmmeter. An electrical test instrument used for lower-value (as compared to high-resistance) electrical resistance measurements. Ohmic Resistance. In defining this resistance: A DC circuit is said to have a resistance of one ohm when one volt will produce a current of one ampere through it. Overcurrent protection A device used …

Power Supply A transformer and rectifier circuit are encased together to supply a lower control voltage. Programmable Logic Controllers An industrial computer that is used to control and execute real-world functions based on the programmed logic. Power Supply Provides power to the PLC and converts the incoming powers to various …

Rebar. A contraction of the term reinforcement bars, which are half-inch wrought-iron rods suspended in poured concrete to give it added strength. Rated Load. The torque value of the connected load that occurs when the horsepower requirements of the driven load equate to the horsepower rating of the motor and …

Sealtight. The trade name for liquid-tight flexible metallic conduit. Semiconductor. A name was given to a group of materials or to compounds of these materials that are neither good insulators nor good conductors of electricity. Because of their four valence electrons (free electrons in the outer shell of the atom), …

Timer A relay that will delay the switching of the contacts by a predetermined time. Totally Enclosed Fan Cooled (TEFC). Normally abbreviated to the acronym TEFC, this term describes motor enclosures with the end bells and the cylindrical motor housing sealed to prevent the entrance of moisture or dirt. Often …