# 9.2

 True/False In a direct current system the supply voltage must be generated at the level required by the load True The points of maximum attraction are called           Magnetic Poles There are three fundamental conditions that must exist before a voltage can be produced by magnetism. One, there must be a conductor in which thevoltage can be produced. Two, there must be a magnetic field in theconductor's vicinity. Three, there must be relative motion between thefield and the conductor. The direction of                is related to the direction of movement of the conductor through the magnetic field. current flow The electron movement is first in one direction, then in the other SINE WAVE True/False The voltage generated by the angular motion of a conductor through a magnetic field describes a sine wave True IN a Sine Wave, each 30° position describes not only the path of the conductor rotating in a two-pole field but the instantaneous values of               at each position voltage induced True/False The effective value of 1.414 peak AC amps is 1 amp DC, therefore the effective value of 1 peak AC amp is 0.707 amps DC True When the voltage or current rises from zero value to maximum and back to zero, it is called an                  alternation A sine wave describes 2 complete                in 360°. A cycle is defined as two               in a period of time. alternations, alternations Frequency is measured in cycles per second or HERTZ. Typically, the frequency of power systems in North America is              60 hertz What are some advantages of three-phase power over single-phase power Generators operate more efficiently and have better regulationgenerating three-phase power.The transmission of power is cheaper due to the use of 25% less conductor material.Three-phase motors are superior to single phase motors in cost and operating characteristics. Ohm's law that states that current is directly proportional to                        applied voltage True/False If AC voltage is applied to a resistance, the resultant current will be a sine wave True When two waves are precisely in step with one another they are said to be IN PHASE Waves do not go through their maximum and minimum points at the same instant of time, the waves are said to be OUT OF PHASE To further describe the phase relationship between two waves, the terms LEAD and LAG are used. The amount by which one wave leads or lags another is measured in               degrees True/False It is possible for one wave to lead or lag another by any number of degrees, except zero or 360 True Total opposition to current flow in an AC circuit is called IMPEDANCE True/False It is the impedance of an AC circuit that may cause the voltage or current to be out phase with each other. True What are the oppositions to current in an AC circuit RESISTANCE, CAPACITIVE REACTANCE, and INDUCTIVE REACTANCE True/False In a DC circuit, the net opposition to current flow in a circuit is composed of only one electrical value -- RESISTANCE True The opposition to current flow that is produced merely by a conductor's inability to perfectly conduct current is resistance Resistance The transfer of energy through the electrostatic field surrounding the conductor is known as CAPACITANCE True/False The greater the "rate of change" in voltage, the greater the capacitance on the circuit True True/False In capacitive circuits, current leads voltage True True/False In an inductive circuit, the current leads the applied voltage False - lags The transfer of energy through the electromagnetic field surrounding the conductor is known as Inductive Reactance During the out-of-phase periods, the product of the Voltage and Amps produces a negative value. This portion of the circuit is known as                    . Reactive Power or VAR (Volt Amperes Reactive) True/False VAR is the portion of the circuit's energy that is used to support electromagnetic and/or electrostatic fields True The product of the applied voltage and the total circuit current ( I× E) Apparent Power The product of apparent power and power factor True power True/False True Power is the product of the applied voltage and the portion of the circuit current that are "in-phase" with the voltage. True The energy that reacts to changes in the circuit Reactive Power (VAR) VAR is the product of the applied voltage and the portion of the circuit's current that is                   with the voltage "out-of-phase" True/False The current flowing in one winding of a DELTA-connected transformer are less than the current flowing on the one phase of the line supplying the bank True True/False Bank ammeters read the phase current of the circuit. True One of the benefits of a DELTA system is that one phase of a three phase bank can be removed and operated                . The capacity of the bank is reduced to approximately              ; however, the three-phase system can continue to operate. OPEN DELTA, 58% True/False The current flowing in one phase of a WYE connected bank is the same as the current flowing in the line supplying the bank True The voltage across one winding of a WYE connected transformer is always                the line voltage of the supply circuit less than Generally the voltmeters on a power bank convert            voltage to              voltage. Therefore; Meter volts = line volts phase, line Any physical quantity that has both magnitude and direction, such as force or velocity, is called a                   . vector quantity AuthorBenjammincash ID355183 Card Set9.2 DescriptionElectromagnetic Induction and Generation Updated2021-04-25T21:34:58Z Show Answers