# Term1fundamentals

 What is an Isolation Transformer? A transformer that has its secondary winding physically and electrically isolated from the primary winding. What is the transformer? A magnetic device that changes the voltage, current, and impedence without changing the frequency. What are the common transfomer efficiencies? 90% to 99% full load. Define power factor. What is the calculation? Ratio of real power to apparent power.Watts/VA In what form is energy of a capacitor stored\? electrostatic field In what form is energy of a inductor stored? electromagnetic field What is a dielectric? Insulating material. Define Inductive Reactance The current limiting property of an inductor in an AC circuit. Define Capactive Reactance The current limiting property of a capacitor in an AC circuit State Kirchhoff's Current Law The sum of the currents entering and leaving a point must equal zero. State Kirchhoff's Voltage Law The sum of the voltage drops and voltage sources in a closed circuit must equal zero. Name three factors that determine the amount of induced voltage in a coil. number of turns of wirestrength of the magnetic field (flux density)speed of the cutting action What is frequency? The number of complete cycles per second. List 3 factors that determine the capacitance of a capacitor. Surface area of the platesDistance between the platesStrength of the dielectric Explain the current and voltage relationships from phase to line in a wye and delta. wye: Line voltage = root3 * phase voltagedelta: Line current = root3 * phase current What is the equation for power in a 3-phase load? Line: P = root3*V*IPhase: P= 3*V*I What is a Coulomb? quantity measure of electrons. 6.25*10^18 Define Ampere rate of electron flow. C/s Define Voltage Electric Potential. The force that pushes electrons through a wire. J/C define Ohm Resistance to current flow (V/A) Define Watt Amount of power being used by a circuit. Energy change must occur to produce watts. J/s How can the polarity of an electromagnet be determined if the direction of current flow is known? Left hand rule. Thumb in the direction of the north pole. Fingers in the direction of current flow Define Flux Density magnetic flux lines per square inch. strength of the magnetic field. Define Saturation when the magnet's strength is increased only slightly with an increase of current. Define Residual Magnetism The amount of magnetism left in a material after the current has stopped What range of electric current generally causes death and how? 50-200mA. Fibrillation of the heart. What is a ground fault? An unintended current path to ground. Define Ohm's Law Mathematical relationship between voltage, current, and resistance V=IR What determines the polarity of magnetism when current flows through a conductor? Direction of current flow. What determines the strength of the magnetic field when current flows through a conductor? Amount of current. What is a vector? A line that indicates both magnitude and direction. Authorjuliav ID217232 Card SetTerm1fundamentals DescriptionTerm 1 Fundamentals Updated2013-05-02T15:22:05Z Show Answers