Download Cathodic Protection Tester 1 Exam 100% Complete and Verified and more Exams Physics in PDF only on Docsity! Cathodic Protection Tester 1 Exam 100% Complete and Verified Electrons are particles of an atom that carry a? Negative charge ________ is an electromotive force or a difference in potential expressed in volts Voltage emf = electromotive force E = Voltage rise across the voltage source of electrical energy.(battery, pipe to soil potential) V = Voltage drop across a sink of electrical energy (resistor) __________ Is the flow of charges along a conducting path and is measured in amperes Current (I) What are the symbols used for current? I (any unit of current) , A (ampere or amps), mA (Milliamps) , μA (Microamps) _________ flows constantly in one direction in a current Direct current (DC) ____________ regularly reverses direction of flow, 100 or 120 times per second. Alternating current (AC) ________ is a relationship between the ratio of voltage to current and resistance of a circuit Ohms law _______ is the rate at which energy is used by an electrical device Power Power is measured in what? Watts (W) Equation for power = P(power in watts) = E(voltage in volts) X I(current in amps) or I(current)^2 X R (resistance) This law states that the sum of Source voltages around in a closed loop of a series circuit is equal to the sum of the voltage across the resistance is in that loop Voltage Law In series circuits what must happen? Voltage must be the same Resistor some should add up to equal total voltage This law states that as much current flows away from a point as towards it Current law The three rules for a parallel circuit Voltage drop crossed each branch is the same and is equal to the source voltage. Total current flowing into and out of the junction point of the branches equals the sum of the branches currents. The total equivalent resistance is always less than the smallest resistance in the current. _________ Maybe used to increase or decrease voltage or to isolate an incoming voltage source from the outgoing voltage. Transformer The transformer has a limited iron core with two sets of windings these are called? Primary and secondary The primary winding is connected to the? Voltage source The secondary winding is connected to? The unit to which voltage is to be supplied Where are taps located? In the secondary winding so that several voltage adjustments are possible ________ is the total opposition that a current presents to an alternating current, similar to resistance in the direct current circle. Impedance impedance symbol Z An instrument that has a needle that rotates across the meter face and indicates the reading on a scale? Analog meter Hybrid meters that are electronic with analog displays (electronic amplifiers driving in electro mechanical coil) or sometimes referred to as? Electronic meters When using an analog meter the reference electrode is connected to which terminal to obtain an upscale reading? Positive terminal For low voltage ranges the circuit resistance becomes more sensitive an external resistance to such as those associated with test leads in reference electrode to electrolyte contact me causing air in the reading Voltmeters Voltmeter ranges in DC 200 millivolts = current shunt readings 2 volts = structure to electrolyte potential In the galvanic series, the more active metals Well corrode if connected to less active metal In a corrosion sell, which of the following is not required? Oxygen The portion of the metal that is corroding is called the? Anode At the anode in an electro chemical corrosion cell, Positively charged ions leave the anode and enter the electrolyte In a galvanic series, compared to noble metals, the more active metals Have a tendency to corrode more easily Compared to an impressed current system, a galvanic anode system in soil has which of the following advantages? No external power source is needed Compared to magnesium anodes, zinc anodes tend to have a More noble open circuit potential In an impressed current system The rectifier positive terminal is connected to the anodes NACE Criteria for Underground Steel Pipe A negative potential or voltage of at least -850 mV relative to copper copper sulfate (CCU)reference electrode. A minimum of 100 mV of cathodic protection between the structure surface and a stable reference electrode contacting the electrolyte Anode = positive Cathode = negative Electrolyte = is an ionized solution capable of conducting electricity Metallic path flows? Cathode to Anode TRUE or FALSE In a galvanic system anodes should be more reactive than the cathode or steel structure? True protons are ____ charged , electrons are ___ charged, and neutrons have ___ charged Positively, Negatively, No Ohm's Law V = I = R = volts (current x resistance) amps (voltage / resistance) ohms (voltage / current) Is the opposition that a charge encounters when through a material, measured in ohms. Resistance Resistance is lowest when? • Low resistance media (high conductivity) • Short length for current flow • Large area of current flow Resistance is greatest when? • High resistance media (low conductivity) • Long path length for current to flow • Small cross-sectional area of current flow This law states that the sum of the source voltages in a simple circuit is equal to the sum of the voltage drops across each resistor Voltage Law This law states that as much current flows away from a point as flows toward it? Current Law ________ is the total opposition that a circuit presents to alternating current similar to resistance in a DC circuit Impedance Electrically charged atoms are referred to as? Ions Negatively charged ions are called Anions Positively charged ions are called? Cations What are Amphoteric Metals? (Aluminum and Lead.) corrosion increases for these metals in an environment with pH levels above 8 __________ is the loss of electrons, which leaves a positively charged Ion. The electrode or metallic site where oxidation occurs is called an ______. Note: The term oxidation does not refer to oxygen Oxidation, Anode ___________ is addition of electrons to a molecule, which forms a negatively charged ion or neutral element. The electrode or metallic site where reduction occurs is called a _________. Reduction, Cathode Chemical reaction that occurs at the anode is an ___________ reaction. Resulting in a loss of electrons. Oxidation Chemical reaction that occurs at the cathode is a _________ reaction. Resulting in the gaining of electrons. Reduction Cations move away from the anode toward the cathode. Anions move away from the cathode toward the anode is called? Electrolytic current flow Compared to zinc anodes of the same size and shape, magnesium anodes Will deliver higher current in a high soil resistivity Typically a cathodic protection rectifier will have a? Transformer Rectifying element Voltmeter in ammeter If the external circuit resistance of a constant voltage rectifier increases by two times, the following will occur The current will be reduced by one-half Test stations are installed for which of the following purposes? (Select all that apply) To obtain structure to electrolyte potential's To confirm the effectiveness of underground isolating fittings To confirm the isolation of road crossings To measure the amount and direction of current in a pipeline Typically a constant voltage cathodic protection rectifier will not have: Transistor Impressed current anode beds may be installed in the following configuration. (Select all that apply) Remote shallow vertical anodes Remote shallow horizontal anodes Deep vertical anodes Distributed shallow vertical anode's Typical source is a straight currents are? (Select all that apply) Cathodic protection systems DC transit systems Telluric Currents