Cathodic Protection Tester 1 (CBT study guide) with Complete Solutions

Electrons are particles of an atom that carry a? - ANSWER-Negative charge ________ is an electromotive force or a difference in potential expressed in volts - ANSWER-Voltage emf = - ANSWER-electromotive force E = - ANSWER-Voltage rise across the voltage source of electrical energy.(battery, pipe to soil potential) V = - ANSWER-Voltage drop across a sink of electrical energy (resistor) __________ Is the flow of charges along a conducting path and is measured in amperes - ANSWER-Current (I) What are the symbols used for current? - ANSWER-I (any unit of current) , A (ampere or amps), mA (Milliamps) , μA (Microamps) _________ flows constantly in one direction in a current - ANSWER-Direct current (DC) ____________ regularly reverses direction of flow, 100 or 120 times per second. - ANSWER-Alternating current (AC) ________ is a relationship between the ratio of voltage to current and resistance of a circuit - ANSWER-Ohms law _______ is the rate at which energy is used by an electrical device - ANSWER-Power Power is measured in what? - ANSWER-Watts (W) Equation for power = - ANSWER-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 - ANSWER-Voltage Law In series circuits what must happen? - ANSWER-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 - ANSWER-Current law The three rules for a parallel circuit - ANSWER-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. - ANSWER-Transformer The transformer has a limited iron core with two sets of windings these are called? - ANSWER-Primary and secondary The primary winding is connected to the? - ANSWER-Voltage source The secondary winding is connected to? - ANSWER-The unit to which voltage is to be supplied Where are taps located? - ANSWER-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. - ANSWER-Impedance impedance symbol - ANSWER-Z An instrument that has a needle that rotates across the meter face and indicates the reading on a scale? - ANSWER-Analog meter Hybrid meters that are electronic with analog displays (electronic amplifiers driving in electro mechanical coil) or sometimes referred to as? - ANSWER-Electronic meters When using an analog meter the reference electrode is connected to which terminal to obtain an upscale reading? - ANSWER-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 - ANSWER-Voltmeters Voltmeter ranges in DC - ANSWER-200 millivolts = current shunt readings 2 volts = structure to electrolyte potential 20 volts = structure to electrolyte potential's and rectifier voltage output 200 volts = rectifier voltage output 1000 volts = unknown voltage Resistors are placed parallel to the moving coil to shut a significant portion of the total current around the moving coil. - ANSWER-Ammeter Ammeter current ranges - ANSWER-200 microamps 2 milliamps 20 milliamps 200 Milliamps 2 amps 10 amps Measures the current flow caused by known voltage source and indicates resistance on the scale or read out - ANSWER-Ohmmeters Find limited use in corrosion work - ANSWER-Ohmmeters Ohmeters are useful for what? - ANSWER-For checking circuit continuity and for other testing and of rectifiers or resistor panels. However, they are not suitable for testing resistance between structures in an electrolyte for two reasons When measuring a structure to electrolyte potential, it is important to eliminate IR drop across which of the following?(select all that apply) - ANSWER-Connection points Through the soil Metallic Path Reference electrode soil contact If a structure to electrolyte potential of -.850 Volts to copper sulfate is measured which of the following conversions to another electrode is correct? - ANSWER-+266 mV to Zinc To calculate resistivity using the Wenner 4- pin method, the following measured value is used? - ANSWER-Resistance In the equation used to calculate the resistivity using the Wenner 4-pin method, R represents; - ANSWER-Resistance in ohms Which is a more active metal? - ANSWER-New steel in freshwater Electronic circuitry with digital display - ANSWER-Digital meters Which meter would be more useful if you were in an area with stray current? - ANSWER-An analog meter would be more useful than a digital meter When using a digital meter the reference electrode is connected to which terminal to obtain the proper polarity reading? - ANSWER-Negative terminal Electronic circutly and Analog displays - ANSWER-Hybrid metery How is a voltmeter used to take a reading? - ANSWER-Connected across the circuit element (parallel) While using a voltmeter what is in between the leads internally? - ANSWER-High resistance Typical uses for the voltmeter? - ANSWER-Structure to electrolyte potential's, rectifier input (AC volts), rectifier output (DC volts), voltage drop across shunts. What are we measuring with a ammeter and what is it in units? - ANSWER-Current and in Amperes How is the ammeter hooked up taking a reading and what is between the leads internally? - ANSWER-Connected in series with the circuit and very low resistance In a series circuit what has to happen? - ANSWER-Total resistance equals the sum of the individual resistances According to Kirchhoff laws the, - ANSWER-Some of the power voltages equal the sum of the voltage drops across the circuit resistances In a series electrical circuit - ANSWER-Kirchhoff voltage law is obeyed Which of the following is true about an electrical chemical corrosion cell? - ANSWER-As polarization increases current will decrease. The weight of any material deposited on the catheter release from the anode is? - ANSWER-Directly proportional to the current In a anodic process - ANSWER-Positively charged ions leave the anode and enter the electrolyte Resistance is measured in? - ANSWER-Ohms (Ω) In a corrosion cell, electrons flow in the direction of? - ANSWER-Anode to cathode through the metallic path Conventional current is in the direction of? - ANSWER-Anode to cathode through the electrolyte In the galvanic series, the more active metals - ANSWER-Well corrode if connected to less active metal In a corrosion sell, which of the following is not required? - ANSWER-Oxygen The portion of the metal that is corroding is called the? - ANSWER-Anode At the anode in an electro chemical corrosion cell, - ANSWER-Positively charged ions leave the anode and enter the electrolyte In a galvanic series, compared to noble metals, the more active metals - ANSWER-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? - ANSWER-No external power source is needed Compared to magnesium anodes, zinc anodes tend to have a - ANSWER-More noble open circuit potential In an impressed current system - ANSWER-The rectifier positive terminal is connected to the anodes NACE Criteria for Underground Steel Pipe - ANSWER-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 = - ANSWER-positive Cathode = - ANSWER-negative Electrolyte = - ANSWER-is an ionized solution capable of conducting electricity Metallic path flows? - ANSWER-Cathode to Anode TRUE or FALSE In a galvanic system anodes should be more reactive than the cathode or steel structure? - ANSWER-True protons are ____ charged , electrons are ___ charged, and neutrons have ___ charged - ANSWER-Positively, Negatively, No Ohm's Law V = I = R = - ANSWER-volts (current x resistance) amps (voltage / resistance) ohms (voltage / current) Is the opposition that a charge encounters when through a material, measured in ohms. - ANSWER-Resistance