Maintenance Test Study Guide: Essential Insights

Maintenance Test Study Guide The best way to protect a pressure gauge from pressure surges is by A. installing a shutoff valve. B. disconnecting the gauge. C. installing a plug valve. D. using a snubber with the gauge. D. using a snubber with the gauge. Hydraulic lines should NEVER be constructed of A. galvanized pipe. B. Teflon-lined hose. C. tubing. D. black steel pipe. A. galvanized pipe. The purpose of a bypass line around a system filter is to A. regulate pressure. B. allow passage of flow in case of emergency. C. offer less resistance to flow than bushings. D. require less space than bushings. B. allow passage of flow in case of emergency. If a cylinder has an input pressure of 50 psi and the BLANK SIDE of the piston is 5 sq. inches, how much total force is applied by the piston? A. 5 lbs. B. 10 lbs. C. 50 lbs. D. 250 lbs. D. 250 lbs. A 40% pressure drop across an oil filter screen indicates that the A. screen is broken. B. line pressure is too low. C. screen is dirty. D. line pressure is too high. C. screen is dirty. An air-breather is installed on a fluid reservoir to A. allow overflow. B. cool the oil. C. vent the reservoir. D. control air pollution. C. vent the reservoir. Which best describes the piston surface area of a single-rod, double-acting piston? A. Spring-loaded B. Unequal C. Equal D. Balanced B. Unequal What kind of valve allows flow in only one direction? A. Needle B. Check C. Gate D. Globe B. Check Pressure on a fluid is A. higher at the inlet. B. distributed equally in the fluid. C. lower than input pressure. D. higher than input pressure. B. distributed equally in the fluid. Shutting the fluid discharge of an air-operated reciprocating pump will cause the pump to A. reverse direction. B. lift the relief valve. C. overstroke. D. stall. C. overstroke. The main difference between pneumatic cylinders and hydraulic cylinders is that hydraulic cylinders A. are more easily repaired. B. require return lines. 1 / 13 B. require return lines. C. are lighter in weight. D. have a greater size selection. Peak hydraulic system demands may be met by the use of A. an accumulator. B. a dual system. C. a large reservoir. D. an oversize pump. A. an accumulator. Air leaving the exhaust port of a four-way valve is directed to the A. Aftercooler. B. Atmosphere. C. receiver. D. Compressor. B. Atmosphere. In troubleshooting a pneumatic system, you should first check A. the air supply. B. the solenoid valve. C. for blown fuses. D. For leaking cylinders. A. the air supply. The speed of a piston is determined by the A. amount of metered outlet air. B. size of the piston. C. size of the solenoid valve. D. Limit switch. A. amount of metered outlet air. The safe operating speed of an air motor is controlled by the A. load. B. speed reducer. C. regulator D. Limit switch. A. load. Install an air lubricator in a pneumatic system A. before the separator. B. after the regulator. C. before the regulator. D. After the separator, but before the regulator. B. after the regulator. Post heating welded metals A. eliminates adhesions. B. prevents oxidation. C. provides more ductility. D. avoids stresses from quick cooling. C. provides more ductility. Before opening the tank valve on an oxygen cylinder which is connected to an oxyfuel cutting torch, you should turn the diaphragm screw A. all the way out. B. 12 of the way out. C. 2/3 of the way out. D. all the way in. A. all the way out. An advantage of brazing over welding is that with brazing, A. dissimilar metals can be joined. B. a hotter flame may be used. C. no flux is used. D. the fusion is better. A. dissimilar metals can be joined. Metallic electrodes for steel alloys should contain A. alloys approximately the same as those of the base metal. B. alloys in addition to those of the base metal. C. no alloys. Any good mild steel rod is satisfactory. D. one of any of the alloys of the base metal. A. alloys approximately the same as those of the base metal. When arc welding light gauge metal (less than [ Thick) in the vertical position, the welding should be done A. from the top down. A. from the top down. 2 / 13 B. from the bottom up. C. both ways from the middle. D. alternately from top and bottom. The first pass in a bevel pipe weld is called the A. root pass. B. included pass. C. lap pass. D. tack pass. A. root pass. In an oxygen cutting job, the greatest safety hazard is the A. possibility of asphyxiation. B. danger of burning the eyes. C. stream of sparks and molten metal. D. ignition of the welded metal. C. stream of sparks and molten metal. Warpage due to welding can be reduced by A. Increasing the amperage. B. welding the reverse polarity. C. increasing the size of the electrode. D. skip or step welding. D. skip or step welding. To arc weld on the structural steel frame of an overhead crane equipped with anti-friction bearings, clamp the ground led to A. the rail of the crane runway. B. the structural member on which you are welding. C. any nearby steel part of the truck assembly that will carry the ground. D. the collector rails. B. the structural member on which you are welding. The primary purpose of peening as welding progresses is to A. condition the surface for further welding B. relieve stresses C. clean the scale from the weld. D. Eliminate pores. B. relieve stresses What is the maximum safe pressure you can have on the low-pressure side of a fuel gas regulator? A.10 psig B. 15 psig C. 25 psig D. 30 psig B. 15 psig Gas torch tips are usually numbered 0 to 15. The larger the number, the A. greater the tip angle. B. smaller the tip orifice. C. larger the tip orifice. D. longer the tip stem. C. larger the tip orifice. A drive sprocket has 15 teeth, and the driven sprocket has 60 teeth. The driven sprocket is damaged and must be replaced, but you only have a 48-tooth sprocket. How many teeth should be on the drive sprocket to maintain the same speed on the machine? A. 12 B. 16 C. 20 D. 190 A. 12 In what kind of a properly lubricated bearing is there no metal-to-metal contact while the shaft is rotating? A. Needle bearing B. Ball bearing C. Journal bearing D. Roller bearing C. Journal bearing Which of the following can transfer power between two turning shafts located at right angles? A. Spur gears 3 / 13 B. Worm gears C. Rack and pinion gears D. Herringbone gears B. Worm gears The best way to keep dirt out of a bearing is to use A. a seal. B. a cap. C. a shield. D. packing. A. a seal. An overload on a torque limiter will most likely cause A. the motor to kick out. B. a bent shaft. C. increased motor torque. D. slippage. D. slippage. When a shaft mounted on two bearings must be positioned axially, A. one bearing should be fixed and the other floating. B. both bearings must be fixed. C. a thrust bearing must be added to this shaft. D. both bearings should be floating. A. one bearing should be fixed and the other floating. Clutches on machinery provide for disengaging and sometimes allow for A. positive drive. B. misalignment. C. slippage. D. variable speed. A. positive drive. Fluid clutches are used on equipment that is subjected to A. shock loading. B. misalignment. C. frequent stopping. D. continuous running. D. continuous running. Selection of gear reducer size is determined by A. Output shaft diameter B. Lubrication capacity C. Horsepower rating and gear ratio D. environment in which it will be used C. Horsepower rating and gear ratio An EP grease would be best suited for which of the flowing? A. High speed, low pressure B. High speed, low temperature C. Low speed, low pressure D. Low speed, high pressure D. Low speed, high pressure The viscosity of an oil is affected most by A. contamination. B. resistance to corrosion. C. pressure. D. temperature. D. temperature. Good lubricating oil must A. Be moist and toxic B. Prevents rust and corrosion C. Be clear in color D. Be readily water soluble B. Prevents rust and corrosion What is the most important quality of oil film lubrication? A. Separates moving surfaces A. Separates moving surfaces A gear pump positive displacement pump is also known as a A. Reciprocating pump B. centrifugal pump C. Rotary pump D. Turbine pump C. Rotary pump In a centrifugal pump, "cavitation" can result in A. a slight increase in discharge pressure. 4 / 13 B. a general improvement in pump performance. C. a reduction in pump net positive suction head requirements. D. pitting of the impeller. C. a reduction in pump net positive suction head requirements. The chemical being pumped determines the required A. casing materials. B. impeller speed. C. casing size. D. impeller size. A. casing materials. In dealing with pumping, the term "static head" means the A. energy demanded by piping system to overcome Friction loss. B. kinetic energy in a flowing liquid. C. vertical distance in feet from liquid level in suction tank to point C. vertical distance in feet from liquid level in suction tank to point of free discharge. of free discharge. D. gauge reading at pump suction plus velocity head. Dowl pins are place in the end caps of pump casing to maintain proper A. Gear-end pump clearance B. Meshing of gears C. bearing placement D. Alignment D. Alignment A positive displacement pump is a pump that A. has positive, unlimited suction capabilities. B. discharges an equal amount of fluid each cycle. C. permits positive control over discharge pressures. D. is suitable only for pumping hydraulic fluids. B. discharges an equal amount of fluid each cycle. Which is a quick opening valve? A. Needle B. Ball C. Globe D. Gate B. Ball When opening a high-pressure steam valve into a cold line, you should? A. Open the valve slowly B. Open the valve quickly C. Open and close the valve several times D. Preheat the line with a torch A. Open the valve slowly A pipe fitting which has both internal and external threads is the A. union. B. bushing. C. reducer. D. coupling. B. bushing. Which of the pipes listed would have the thickest wall? A. Schedule 20 B. Schedule 40 C. Schedule 80 D. Schedule 120 D. Schedule 120 In piping, the designation "250 lb" refers to a fitting's A. material composition. B. weight per section. C. safe pressure rating. D. support capacity. C. safe pressure rating. Pipe joint compounds are used to A. lubricate threads when joining. B. fuse fittings. C. make gaskets. D. seal flanged joints. A. lubricate threads when joining. Which of the valves listed can best be used for throttling? A. Plug cock 5 / 13 B. Butterfly C. Gate D. Globe D. Globe The frequency of operation of a steam trap is governed by A. an automatic timing device. B. the amount of condensate formed in the line. C. the steam pressure in the line. D. the size of the steam line. C. the steam pressure in the line. It is good practice to put slope in steam line installations because it A. eliminates condensate pockets. B. decreases the resistance to steam flow. C. Prevents strain due to expansion. D. allows for expansion. A. eliminates condensate pockets The point at which a pry bar pivots is called its A. lever. B. fulcrum. C. pinch point. D. hinge point. B. fulcrum. A ladder should be set at what fraction of its length from the object being climbed? A. 1/4 B. 1/3 C. 1/2 D. 3/4 A. 1/4 Before cutting a cable, the cable must be A. seized. B. cleaned. C. stretched. D. kinked. A. seized. To lift a heavy load without tipping, fasten the hoist A. above the center of gravity. B. in the middle. C. at one end. D. under its center of gravity. A. above the center of gravity. Hoisting equipment, the term "safety factor" means the A. maximum load the equipment will handle without Breaking. B. ratio between the breaking load and the allowed load. C. maximum load allowed for ordinary use. D. ratio between the allowed load and the actual load. D. ratio between the allowed load and the actual load. When air is compressed, its temperature A. increases. B. decreases. C. and volume decrease. D. and volume increase. A. increases. The major conditions that determine which lubricant should be used are load, temperature, and A. speed of moving parts. B. the type of motion involved. C. how often the machine is used. D. what the machine is used for. A. speed of moving parts. When cutting tubing with a hacksaw, use a blade with A. Different size teeth. B. Coarse teeth. C. Fine teeth. D. Reversed teeth. A. Fine teeth. If a 20-tooth sprocket turns at a speed of 10 rpm, how Many rpm will a 10-tooth sprocket turn 6 / 13 when driven by the Same chain? A. 100 B. 20 C. 10 D. 5 B. 20 In what way does a resisting force always act in relation to an applied force? A. Perpendicular B. Equal and opposite C. Parallel D. On a slant B. Equal and opposite Piece of information needed to calculate the force that A hydraulic cylinder can exert is the A. diameter of inlet pipe. B. piston stroke. C. flow rate. D. hydraulic pressure (psi). D. hydraulic pressure (psi). What tap is best to start cutting a thread in a piece of metal? A. Centering tap B. Plug tap C. Taper tap D. Bottoming tap C. Taper tap What coupler would allow the greatest flexibility? A. Rigid shaft coupler B. Chain coupling C. Gear coupling D. Rubber gear coupling D. Rubber gear coupling Safe operating speed for a grinding wheel is determined by the A. material being ground. B. ambient temperature. C. maximum rpm of the grinder. D. diameter of the wheel. D. diameter of the wheel. If you are going to drill and tap a ½" bolt hole to bolt a machine part to a heavy cast iron housing, what kind of Thread should you use? A. National fine B. Acme C. Square D. National coarse A. National fine Which of the following tools could be used to check shaft or coupling alignment? A. Transit B. Calipers C. Micrometers D. Straightedge and thickness gauge D. Straightedge and thickness gauge What tap is best to cut threads near the bottom of a blind hole? A. Centering tap B. Plug tap C. Bottoming tap D. Taper tap C. Bottoming tap When operating a forklift, A. raise the load as high as possible to avoid obstructing the operator's view. B. only raise the load as high as needed while moving the forklift. B. only raise the load as high as needed while moving the forklift. C. raise the load 3 feet off the ground. D. it doesn't matter how high the load is raised. If a burner were functioning properly and set "rich," which one of the following would NOT be present in an exhaust analysis? A.H2 7 / 13 B. CO2 C. 02 D. N2 B. CO2 A pilot flame detector can be a A. solenoid. B. flame rod. C. regulator. D. pressure gauge. B. flame rod. Combustion air is normally preheated by using which one of the following? A. Recuperator B. Atomizer C. Premixer D. Dampers C. Premixer As flow increases across an orifice plate, the differential pressure developed A. decreases logarithmically. B. increases linearly. C. increases as a square function. D. remains constant. C. increases as a square function. All fires require a source of A. hydrogen. B. oxygen. C. nitrogen. D. heat. D. heat. Perfect combustion will take place when the right amount of fuel is combined with what gas? A. Carbon B. Oxygen C. Hydrogen D. Nitrogen B. Oxygen How many BTU's are there in a therm of natural gas? A. 97,560 B. 100,000 C. 97,560,976 D. 102,500,000 B. 100,000 The quantity of heat necessary to raise one pound of water one degree Fahrenheit is A. a calorie. B. a BTU. C. a therm. D. Celsius. B. a BTU. A synchronous motor controller will start the motor as an induction motor and then A. bring it into synchronization using DC excitation. B. run it as a synchronized DC motor. C. synchronize the stator with the line frequency. D. synchronize the power factor and frequency. D. synchronize the power factor and frequency. A wound-rotor motor is always started with A. no external resistance in the rotor circuit B. a starting or auxiliary winding. C. all the external resistance in the rotor circuit. D. any external resistances open-circuited. C. all the external resistance in the rotor circuit. Dynamic braking is used to A. regulate the speed of a motor. B. mechanically slow the motor down. C. electrically retard or stop a motor. D. derate a motor's horsepower. C. electrically retard or stop a motor. 8 / 13 What causes the current to decrease as an induction motor accelerates? A. Internal resistance B. External resistance C. Stator winding D. Counter EMF D. Counter EMF The formula for determining the synchronous speed of the rotating magnetic field around the stator is A. N=120fP B. N=120P:f C. N=Pf:120 D. N=120f:P D. N=120f:P The main contacts of a reversing starter are connected such that two line wires, of the three feeding the motor, are A. open when forward contacts close. B. interchanged when reversed contacts close. C. shorted for plugging. D. closed for jogging. B. interchanged when reversed contacts close. How many main-line contactor assemblies are used in an across-the-line AC reversing motor control? A. One B. Two C. Three D. Four B. Two Logic functions are a means of expressing pre-determined operations by the use of A. mechanical relays. B. direct transmittal. C. electrical signals. D. servomechanisms. C. electrical signals. When a transistor is used as a relay driver, the relay energizes when the A. collector goes low. B. emitter goes high. C. collector goes high. D. emitter goes low. C. collector goes high. Transistors have an emitter-base junction that must be forward-biased for the transistor to conduct. This means that in A. PNP transistors, the base is positive with respect to the emitter. A. PNP transistors, the base is positive with respect to the emitter. B. PNP transistors, the electrons are the majority carriers. C. NPN transistors, the holes are majority carriers. D. NPN transistors, the base is positive with respect to the emitter. Which of the following is the symbol for current? A. EMF B. kV C. I D. kVA C. I Electrical contacts in a thermostat must be small and, therefore, they cannot handle the supply of current to a motor. The heavier current would be controlled through a A. transformer. B. relay. C. shunt. D. switch. B. relay When a transistor is used as an amplifier, increasing base current will cause an increase in A. collector current only. B. emitter current only. A. collector current only. 9 / 13 C. leakage current. D. collector and emitter current. What is the purpose of connecting a diode across a DC-operated relay coil? A. To eliminate relay chatter B. To increase relay magnetic pull C. To maintain constant DC drop across the relay D. To reduce inductive kick D. To reduce inductive kick The core material in a DC relay consists of A. a coil of copper wire. B. a permanent magnet. C. soft iron. D. laminated plastic. C. soft iron. If the primary coil of a transformer has more turns than the secondary, it is a A. step-down transformer. B. step-up transformer. C. variable transformer. D. fixed transformer. A. step-down transformer. The output frequency of a half-wave rectifier is A. half the AC input frequency. B. twice the AC input frequency. C. the same as the AC input frequency. D. not related to the input frequency. C. the same as the AC input frequency. To properly turn off an SCR once it is conducting, A. remove the gate signal to turn it off. B. use a high speed contactor in series with the anode. C. reverse bias the anode with respect to the cathode. D. reverse bias the gate with respect to the cathode. C. reverse bias the anode with respect to the cathode. To increase the PIV (peak inverse voltage) ability of an SCR circuit (power rectifier), A. connect two SCRs in series. B. increase the snubber capacitor value. C. decrease the snubber resistor. D. parallel to anode inductive reactances. A. connect two SCRs in series. Short circuits in any system are always accompanied by a sudden A. voltage decrease. B. current decrease. C. voltage increase. D. resistance increase. A. voltage decrease. Total opposition to current flow in an AC circuit is expressed as the A. amperes. B. flux density. C. reaction. D. impedance. D. impedance. A100Q resistor carries a maximum current of 400 ma. What is the minimum power rating this resistor should have? A. 8W B. 16W C. 32W D. 40 W D. 40 W According to the electron theory, a flow of current is a movement of A. protons from atom to atom. B. electrons from atom to atom. C. the nucleus around the atom. D. molecules within an atom. B. electrons from atom to atom. 10 / 13 Ohm's Law states the mathematical relationship between current, voltage, and resistance. Solve the following using The Ohm's Law equation. In a DC circuit, if the current is 12 amperes and voltage is 15 volts, what is the resistance? A. 0.75 ohms B. 0.80 ohms C. 0.90 ohms D. 1.25 ohms D. 1.25 ohms Inductance is the property of an electrical circuit that opposes any change in A. voltage. B. current. C. resistance. D. power. B. current. Ohm's Law states the mathematical relationship between current, voltage, and resistance. Solve the following using The Ohm's Law equation. In a DC circuit, if the voltage is 115 volts and resistance is 20 ohms, what is the current? A. 5.75 amps B. 57.5 amps C. 230 amps D. 2300 amps A. 5.75 amps When an alternating voltage is applied to a purely resistive circuit, the A. voltage lags the current. B. voltage leads the current. C. current leads the voltage. D. current is in phase with the voltage. D. current is in phase with the voltage. Ohm's Law states the mathematical relationship between current, voltage, and resistance. Solve the following using The Ohm's Law equation. In a DC circuit, if the current is 35 amperes and resistance Is 7 ohms, what is the voltage? A. 0.20 volts B. 5 volts C. 42 volts D. 245 volts D. 245 volts The greatest current flow in an AC capacitive circuit having a constant line voltage will be at which of the following frequencies? A. 25 hertz B. 30 hertz C. 50 hertz D. 60 hertz C. 50 hertz The effective value of AC voltage and current is also known as the A. RMS value. B. IMS value C. equivalent value. D. average value. A. RMS value. A resistor that is color-coded orange, orange, and brown has a resistive value of A. 22 Q. B. 330Q. C. 44 kQ. D. 2 kS +5%. B. 330Q. In power transmission, a transformer is used to raise the voltage on the sending end and lower the voltage on the receiving end in order to decrease A. corona loss at towers. B. insulator length on units. A. corona loss at towers. 11 / 13 C. eddy currents in breakers. D. wire size of power lines. A single-phase transformer circuit feeds a motor and lighting load of 50 kilowatts. At a power factor of 0.8, the kVA rating of the step-down transformer would be A. 50 kVA. B. 62.5 kVA C. 40 kVA. D. O.016 kVA. B. 62.5 kVA To prevent injury while working on a current transformer, the secondary winding must be A. open. B. connected. C. short-circuited. D. insulated. C. short-circuited. A transformer has 400 turns in the primary and 200 turns in the secondary. If 240 volts are applied to the primary winding, what voltage will be measured on the secondary winding? A. 400 volts B. 240 volts C. 200 volts D. 120 volts D. 120 volts (sheet says B. 120 volts) To display voltage value on a panel voltmeter of a high voltage power line (69 kV), what additional electrical equipment should be added? A. Potential transformer B. Current transformer C. High voltage insulation wire to the panel meter D. Shunt A. Potential transformer An "infinite" (10 megohms or greater) reading on a solenoid coil shows A. a good solenoid. B. a grounded solenoid. C. an open solenoid. D. a short-circuited solenoid. D. a short-circuited solenoid. The potential required to operate a megohmmeter is usually supplied by A. a current transformer. B. the circuit being tested. C. a potential transformer. D. an internal power supply. D. an internal power supply. If the insulation resistance reading, using a megohmmeter, shows a sudden drop, it indicates A. tests are being made at wrong points. B. incorrect voltage used for testing. C. routine inspections are needed. D. developing trouble. D. developing trouble. Because of the manner in which a voltage tester is used, it must have A. low resistance. B. high resistance. C. a multiplier in parallel. D. a movement that indicates plus/minus values. B. high resistance. What is most harmful to the human body? A. Current B. High voltage C High resistance D. Reactance A. Current 12 / 13 Which of the following input operations requires a conversion to digital form prior to input? A. Disc B. Analog C. Contact courses D. Limit switches B. Analog If a programmable controller controls the operation of a motor, what connects the motor controls to the controller? A. RS232 cable B. Line voltage C. 1/O devices D. Modem C. 1/O devices The primary function of a parity bit in programming a programmable controller or computer is to A. change a group of bits to an even number. B. shorten a memory sequence. C. check the accuracy of digital signals. D. enlarge chip storage space. C. check the accuracy of digital signals. The type of electronic component that isolates the stages inside a microprocessor from those outside the microprocessor is the A. buffer. B. bus. C. RAM. D. ROM. B. bus. If you had a flow transmitter that had a 4-20 mA mode output and a recorder that only accepted a 1 to 5 VDC input, what size resistor would you use on the input of the recorder to accommodate the mA signal? A. 250 ohms B. 25 ohms C. 40 ohms D. 400 ohms A. 250 ohms If a control circuit fuse blows when the start button is pressed, what should you check for? A. Short-circuited contact B. Short-circuited coils C. Grounded contacts D. Under-rated fuse A. Short-circuited contact A transducer will A. open an oil circuit breaker when a trip signal is present. B. remove voltage spikes on a transmission line. C. provide lightning protection. D. provide feedback. D. provide feedback. The start button in a motor control circuit is released. The motor starter contacts open, or the coil does not remain energized. The trouble is likely to be in the A. stop switch contacts. B. overload resets. C. holding contact circuit. D. motor starter coil. C. holding contact circuit. 13 / 13