Stationary Engineer Exam Questions and Answers Latest 2024/2025 (Graded)

Stationary Engineer Exam Questions and Answers Latest 2024/2025 (Graded) An AC circuit consists only of a pure inductance and a power source. The relationship between the voltage and the current in this circuit is that the - Answer current lags the voltage The power factor of a load is equal to the ____________ power divided by the ____________ power. - Answer True ; apparent A 10-ohms and 20-ohms resistor are connected in parallel. The total line current drawn by this parallel combination is 30 amps. Under these conditions, the line voltage will be ____________ volts. - Answer 200 A 20-ohm resistor is connected in series with a parallel combination of two resistors, one of which is 10-ohms, the other 40-ohms. If the voltage across the parallel combination is 40 volts, the voltage across the 20-ohm series resistor is ________ volts. - Answer 100 A certain 120-volts single-phase AC circuit has a power factor of 80 percent and a watt-meter reading of 1150 watts. The current drawn by the circuit is _________ amperes. - Answer 12 If the voltage between lines of a 3-phase, 3-wire delta connected system is 2400 volts, then the phase voltage is _____________ volts - Answer 2400 A circuit consists of an inductive reactance of 15 ohms and a resistor of 20 ohms in series across a 100-volts, 60 cycles AC supply. The current in this circuit is ____________ amperes. - Answer 4 A 3 phase, 3 wire, 208 volt, 60 cycles AC service supplies a balanced load consisting of three 30 ohms resistors connected wye. The line current under these conditions os MOST NEARLY ___________ amperes. - Answer 6.9 If the level of the electrolyte in a lead acid storage battery falls below the top of the plates because of evaporations under normal operating conditions, it is BEST to add - Answer Water A 600 volt cartridge fuse must have knife blade contacts if its current rating Stationary Engineer Electric Exam Questions and Answers Latest 2024/2025 (Graded) exceeds _____________ amperes. - Answer 60 When the magnitude of the short circuit currents in a feeder circuit must be limited, this is USUALLY accomplished by means of - Answer reactors The cross sectional area in circular mils of a standard cable having 37 strands, each of which ha a diameter of 90 nils, is MOST NEARLY - Answer 300,000 A coil having an average diameter of 4 inches is to be made up from a 1,260 ft long length of wire. The numbers of turns in this coil will be MOST NEARLY - Answer 1,200 The device commonly known as a growler is FREQUENTLY used to - Answer test DC armature windings for shorts When a megger is applied alternately to the two leads of a direct current electrolytic capacitor, the reading will - Answer start at zero but increase gradually for one of the connections The device used to convert direct current to alternating current is called - Answer inverters Of the following conditions, the one which is MOST likely to cause flashing or excessive arcing from brush to brush in a motor is - Answer Excessively high voltage on the line The currents in the armature equalizer connections in a DC generator are - Answer alternating currents A generating station has one 1000 Kw and two 2000 Kw generators. To supply 2000 Kw MOST economically, the operating conditions should be - Answer one 2000 Kw generator at full load The terminal voltage of a DC shunt generator having an armature current of 100 amperes, an armature resistance of 0.02 ohms, and a generated E.M.F of 222 volts is MOST NEARLY ______________ volts. - Answer 220 The number of poles in the field of an alternator generating voltage at a frequency of 60 cycles per second while rotating at 1200 rpm is - Answer 6 If the field of a shunt motor opens while running, the motor will - Answer run away To reverse the direction of rotation of a cumulative compound motor, and not have it run as a differential compound motor, reverse the connections to the ____________ field. - Answer shunt field and to the series A main contributing factor to motor stator failure usually is - Answer dirt The input of a motor is 40,000 watts and efficiency is 80 percent. The TOTAL energy loss is __________ watts. - Answer 8,000 The full load current of a three-phase 5 hp motor operating at 200 volts, 60 cycles, and having an efficiency of 80 percent and a power factor of 85 percent is MOST NEARLY ____________ amperes. - Answer 14.4 Of the following motors, the one that has the best speed regulation is the motor. - Answer shunt The full load speed of a 60-cycle 208 volt, 3 phase induction motor having 6 poles and operating with a slip of 10% is MOST NEARLY___________ r.p.m - Answer 1080 Of the following, a MAJOR advantage of an AC synchronous motor is that it(s) - Answer can be used for power factor correction If the field current of a synchronous motor is increased to a point which makes the synchronous motor overexcited, the - Answer motor will take a leading current When transformers are to be operated in parallel, it is NOT necessary that the transformer have the same - Answer KVA rating A transformer rates at 200 KVA is FULLY loaded with a lagging power factor of 80% when it is supplying - Answer 160 KW If the current in the primary of a current transformer is 500 amperes and the transformer has a ratio of 100 to 5, an ammeter connected to the secondary will read MOST NEARLY___________ amperes. - Answer 25 Assume that a switchboard ammeter which is connected to a current transformer is damaged and must be removed without interrupting the service. Of the following, an ESSENTIAL precaution to be taken before disconnecting the ammeter is to - Answer short the secondary of the transformer A DC relay is rated at 6 volts and 120 ohms. This relay can be operated from a 120 volt line by connecting a ___________ ohm resistance in __________ with relay - Answer 2280: series Some relays are provided with dash-pots. The FUNCTION of these dash-pots is to provide - Answer delayed time action An ammeter has a full scale deflection for a current of 0.01 amperes and an internal resistance of 20 ohms. In order to have the ammeter read full-scale for a current of 10 amperes and not damage its movement, a shunt should be used having a value of__________ ohms. - Answer 0.02 An air circuit breaker has contacts that flash. The MOST probable cause of this trouble is that the - Answer barriers are broken The MAIN purpose of a shunt trip on a circuit breaker is to - Answer permit the breaker to be opened electrically from a remote location, regardless of load conditions at the breaker The grid-controlled gas-type electronic tube MOST often used in motor control circuits is the - Answer thyratron Under normal atmospheric conditions, a pressure gauge that reads 24 inches of mercury is indicating an absolute pressure of MOST NEARLY_____________ P.S.I. - Answer 26.5 The PRIMARY function of a hydrometer is to measure the rate of - Answer relative humidity A venturi meter is used to measure the rate of - Answer fluid flow The PRINCIPLE thickening agent used in lubricating greases is - Answer metallic soap The specific gravity of liquid is USUALLY determined by means of a - Answer hydrometer The pull required on the fall line (negating friction) to hoist a 120 pounds weight, using a four-part block and tackle, is ___________ lbs. - Answer 30 Of the following terms, the one which does NOT describe a way of finishing the ends of a rope is the - Answer bight When hoisting a load by means of sling, the stress in each leg of the sling will - Answer increase as the angle between the horizontal and the sling leg decreases The MAXIMUM pressure in an upright cylinder 6 feet in diameter, 8 feet high, and open at the top, when filled tot he brim with water, is MOSTLY NEARLY ______________ lbs/. - Answer 500 The MAXIMUM height to which water can be lifted by means of suction alone, at sea level, is APPROXIMATELY _____________ feet. - Answer 34 The TOTAL number of 4 inch diameter pipe that is required to equal the water flow capacity of an 8 inch diameter pipe (negating friction) is - Answer 4 The number of threads, per inch, on the standard machine screw MOST suitable for general use is - Answer 32 The friction losses which occur when water flows through a pipe vary MOST NEARLY _____________ with the ____________. - Answer directly; velocity squared Small by-pass lines are sometimes furnished around large gate valves MAINLY to - Answer balance the pressure on the gate when the valve is being opened The sudden surge caused by an abrupt change in the speed of the pumps in a closed liquid piping system is USUALLY called - Answer water hammer The valve that permits water to flow one direction only is the ____________ valve - Answer check Most flanged butterfly valves can be brought from a fully closed position to a fully opened position in _____________ turn(s). - Answer a quarter The efficiency of two centrifugal pumps operating in parallel is ___________ of one of the pumps operating alone. - Answer practically the same as that Assume that a spur gear having 20 teeth revolves at 80 r.p.m and drives another super gear having 40 teeth. The speed at which the gear having 40 teeth revolves is _____________ r.p.m. - Answer 40 A centrifugal pump has a plain flat-joint seal between the impeller and the casting. If the clearance of the seal become enlarged due to wear, thereby reducing the pump's efficiency, it would be GOOD practice to - Answer renew the impeller The one of the following statement which CORRECTLY describes a speed characteristic for a centrifugal pump under normal operating conditions is: - Answer Total head varies directly with the square of the speed The MAIN function of a pump stuffing box is to - Answer protect the pump against leakage at the point where the shaft passes through the pump casting The PROPER order of the event that takes place in a stroke internal combustion engine - Answer Air intake, compression, power expansion, and exhaust The number of cycles in an internal combustion engine is AT LEAST ____________ cycles. - Answer two The lumens per watt taken by a lamp varies with the types and size of lamp. Given that one candlepower light source emits 12.57 lumens, the lumens per watt taken by a 75 candlepower lamp drawing 40 watts is APPROXIMATELY - Answer 23.6 A 230 volt, 25 cycle magnetic brake coil to be rewound to operate properly on 60 cycles at the same voltage. Assuming that the coil 25 cycles has 1800 turns, at 60 cycles the number of turns should be - Answer reduced to 750 Nichrome wire having a resistance of 200 ohms per 100 feet is to be used for a heater requiring a total resistance of 10 ohms. The length, in feet, of wire required is - Answer 50 The MAIN reason for grounding conduit is to prevent the conduit from becoming - Answer accidentally energized at a higher potential that ground A feeder consisting of a positive and a negative wire supplies a motor load. The feeder is connected to bus-bars having a constant potential of 230 volts. The feeder is 500 ft long and consists of two 250,000 circular-mil conductors. The maximum load on the feeder is 170 amps. Assume that the resistance of 1000 ft. of this cable is 0.0431 ohm. The voltage, at the motor terminals, is MOST NEARLY With the reference to Question 29, the efficiency of transmission, in percent, is MOST NEARLY - Answer 217V; 97% With reference to AC motors, in addition to overload, many other things causes fuses to blow. The fuse will blow if, in starting an AC motor, the operator throws the starting switch of the compensator to the running position - Answer too quickly A change in speed of a DC motor of 10 to 15 percent USUALLY be made by - Answer increasing or decreasing the gap between the armature and field Of the following types of fire extinguishers, the one MOST suitable for use on fires in electrical equipment is the ____________ extinguisher - Answer dry chemical Portable fire extinguisher suitable for use on electrical fires are USUALLY identified by a label with the following symbol __________ in a __________. - Answer C; circle When flammable liquids are poured form one containers to another, a bond wire is some-times connected between the containers to - Answer eliminate sparks due to static electricity The proper way to lift a heavy object includes all of the following techniques EXCEPT - Answer Placing the feet as a far away from the object as possible The contents of different piping systems are sometimes are sometimes identified by means of standard color codes, such as the one recommended by the American National Standards Institute (formerly the American Standard Institute). According to this Institute's standards, a piping system used for fire protection should be designated by the color - Answer red Assume that the contents of a container are described as TOXIC. This means they are - Answer poisonous An authoritative source of emergency information on antidotes is the - Answer Poison Control Center, Department of Health Unexpected operation of electrical equipment that can be started by remote control may cause injury to workers making repairs. Before making repairs on such equipment, it is GOOD practice to - Answer follow a lockout procedure Assume that one of the men under your supervision asks you a technical question to which you do not know the answer. Of the following, it is BEST that you - Answer tell him that you do not know the answer but that you will get the information for him In order standard cartridge fuses, it is necessary to specify only the - Answer current capacity of the circuit and the power to be dissipated