Stationary Engineer Electric Exam Questions with All Correct Answers

Stationary Engineer Electric Exam Questions with All Correct Answers 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 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