In a single-phase transformer, the core loss is 60 W at 40 Hz and 95 W at 60 Hz both measured at the same maximum value of flux density. Find the core losses in W at a frequency of 50 Hz.

What is VBN in this balanced three-phase in which VAN = 7200∠20° and VCN = 7200∠-100°.

87 is the device function number assigned by ANSI to this relay

A load consists of a resistnace R in parallel with a capacitor of reactance X. The load is fed from a single phase supply through a line of impedance 8.4 + j11.2 ohms. The rms voltage at the load terminal is 1200 at 0 degrees V rms, and the load is taking 30 kVA at 0.8 power factor leading. Find the supply voltage

A piece of conductor 10 cm long moves across the magnetic field of 10 kgauss at a velocity of 120 cm/s. What is the voltage across the conductor?

Renewable Energy Act of 2008 refers go what Republic Act?

A power plant supplying energy to a city will usually experience peak demand

The effect of corona is

Receptacle outlet that is part of the luminaire or appliance, located within cabinets or cupboards shall be located not more than ___ mm, above the floor.

An electromagnet has an air gap of 3 mm an the flux density in the gap is 1.257 Wb/m². Calculate the ampere-turns required for the gap.

In an antique automobile, a 6-V battery supplies a total of 48 W to two identical headlights in parallel. The resistance (in ohms) of each bulb is

An electric kettle was marked 500 watts, 230 volts and was found to take 15 minutes to bring 1 kg of water at 15°C to the boiling point. Determine the heat efficiency of the kettle.

A DC system can be protected from lightning buly including a thyrite tube in the circuit that connects the high voltage line with the ground. Which of the following is FALSE regarding a thyrite tube?

The phase angle for a series RC circuit may be computed as the angle between the ____ and ___ phasors.

Which of the following methods of generating electrical power from the sea water is more advantageous?

The purpose of a grid system is to

Which of the following type of fault that used only yhe equivalent positive impedance of the circuit in the short-circuit calculation?

A three-phase, 345-kV transmission line has a series impedance of (4.0 + j60.0) Ω and a shunt impedance of j2.0 x 10-3 S. Using a 100 MVA and the line voltage as base values, calculate the per-unit shunt admittance of the line.

In long transmission line, at no-load, the receiving end voltage as compared to the sending end voltage is: I. Higher II. Lower III. Remains the same

What type of transformer bank is used to convert 2-phase to 3-phase power?

A 500-kVA alternator operates at full-load kVA output at an efficiency of 93.5 percent. If the load p.f. is 0.83, calculate the total loss.

A 230 V DC series motor is connected to 230 V AC. It will?

A current is clockwise around the outside edge of this page and a uniform magnetic field is directed parallel to the page, from left to right. If the magnetic force is the only force acting on the page, the page will turn so the right edge:

Is any building, room or separate place which houses or encloses electrical supply equipment connected to transmission or distribution lines and the interior of which is accessible, as a rule, only to properly qualified persons.

A parallel plate capacitor with plates of area A that are separated a distance d by air is initially charged with charge q. The energy stored in the capacitor initially is E. The plates are then separated by 2d. What is the new energy stored in the capacitor?

Which of the following shall be included in the calculation of the reliability standard indices of the distributor asset by the Philippine Distribution Code?

A three-phase short transmission line having per phase impedance of 2 + j4 ohms has an equal line to line receiving end and sending end voltages of 115 kV, while supplying a load of 0.8 p.f. leading. Find the power supplied by the line?

For constant transmission efficiency, voltage is increased n times, the size of the conductor would be

Nine identical wires, each of diameter d and length L, are connected in "series". The combination has the same resistance as a single similar of wire of length L but whose diameter is:

A single-phase transformed rated 100 KVA, 2.4 KV/ 240 V. If 240 V winding is short-circuited, the rated current flows when the voltage applied 2.4 KV winding is 1.054 KV. The power input is 3.89 KW. What is the value of the reactance referred to high-voltage winding?

This is the compact arrangement of switching devices

Which of the following is/are the drawbacks of SF6 circuit breakers? I. Sealing problem of gas II. Ingress of moisture in the gas system is dangerous

What can usually be assumed as the driving or source voltage for fault and voltage calculation in per unit method?

The phenomenon of rise in voltage at the open circuited or slightly loaded line is called.

In a curcuit breaker, the time duration from the instant of the fault to the extinction of arc is known as

What is a protective device designed to protect an individual against electric shock?

The 'hum' in a transformer is due to

Which statement is TRUE?

Electrotechnical Commission's (IEC) Technical Committee 57 reference architecture for electric power systems

A loop of wire carrying a current of 2.0 A is in the shape of a right triangle with two equal sides, each 15 cm long. A 0.7 T uniform magnetic field is in the plane of the triangle and is perpendicular to the hypotenuse. The resultant magnetic force on the two sides has a magnitude of:

The effect of electric shock in the human body will depend on

Two single phase transformer are connected in open-delta supplying three phase load 150 kVA at 80 percent power factor and a single phase load of 30 kW at unity power factor connected across line A and C. What should be the rating of each transformer so it would not exceed to its rating?

For a nuclear power plant, the useful life is expected to be about

Which of the following statements about induction motors is FALSE?

In an RLC series circuit, the source voltage is leading the current at a given frequency f. If f is lowered slightly, the circuit impedance will?

Determine the GMR of a three equal strands conductor in vertical formation in terms of "r" in individual strand

Silica gel prevents air moisture from entering the outdoor transformer tank. It is placed in

A source with an impedance of 100 Ω is connected to the primary coil of a transformer and a resistance R is connected to the secondary coil. If the transformer has 100 turns in the primary coil and 100 turns in its secondary coil, the greatest power will be dissipated in the resistor if R ___ ohms.

A rice mill will be served by two unuts of 50 kVA transformers, 7.620 kV/240 V. The transformers will be installed as open-delta bank to serve the three-phase load of the rice mill. What is the maximum kVA load that this bank can carry without overloading?

A coulomb:

Heating value of coal largely depends on

What is the IEEE device number for an AC time overcurrent relay?

An act reducing electricity rates by allocating a portion of the Net National Government Share from the Malampaya Natural Gas Project for the Payment of the Stranded Contract Costs and Stranded Debts

What is the equivalent IEEE device function number for directional power relay

Radio receivers are usually tuned by adjusting the capacitor of an LC circuit. If C = C1 for a frequency of 600 kHz, then for a frequency of 1200 kHz one must adjust C to:

A transformer is rated 1 kVA, 220/110 V, 60 Hz. Because of an emergency this transformer has to be used on a 50 Hz system. If the flux density in the transformer core is to be kept the same as at 60 Hz and 220 V, what is the kilovolt-ampere rating at 50 Hz.

In a power plant, a reserve generating capacity which is in operation but not in service is known as?

ACSR conductor having 7 steel strands surrounded by 25 aluminum conductors will be specified as?

Which of the following insulators will be selected for high voltage application?

A capacitor in an LC oscillator has a maximum potential difference of 15 V and a maximum energy of 360 microJ. At a certain instant the energy in the capacitor is 40 microJ. At that instant what is the potential difference across the capacitor?

In a three-phase loop network, we get the following equations by Kirchoff's Law: 159I1 - 50.9I2 = 1 407I1 - 2,400I2 + 370I3 = 1 142I2 - 380I3 = 1

MERALCO has two single-phase transformers with equal turns ratio and ratings are operated in parallel to supply a load of 280 kW at 0.8 lagging pf. Transformer A has a resistance of 2% and a reactance of 8%. Transformer B has a resistance of 1% and a reactance of 6%. Determine the power delivered by the transformers A and B to the load.

The distributor shall design and operate its system to assist the system operator on maintaining its fundamental frequency within the limits of ___ Hz to ___ Hz during normal conditions.

A balanced delta connected load has impedance Z1=Z2=Z3. What is per phase equivalent impedance in wye?

If 25 ohms and 125 amperes are the base impedance and base current, respectively for a given system, what is the base KVA?

A certain amount of currentbdlows through a ring-shaped coil with fixed number of turns. How does the magnetic induction B varies inside the coil if an iron core us threaded into coil without dimensional change of coil?

For proper parallel operation, ac polyphase alternators must have the same?

A cylindrical copper rod has a resistance R. It is reformed to twice its original length with NO change of volume. What is the new resistance?

The primary of a 3 : 1 step-up transformer us connected to a source and the secondary is connected to a resistor R. The power dissipated by R in this situation is P. If R us connected directly to the source it will dissipate a power of

In pursuant to Republic Act No. 11361 or Anti-Obstruction of Power Line. The penalty of arresto mayor(First Offense) will cost?

If the reference bus is changed in two load-flow runs with the same system data and power obtained for reference bus taken as specified P and Q un the latter run

What instument measures the insulation of a powerline?

A dc ammeter has an internal resistance of 0.1 ohm. A shunt of 1.01 x 10-3 ohm is connected to the ammeter. What is the multiplier of the set up?

When a power plant is not able to meet the demand of consumersit will resort to?

The winding of a power transformer usually develops short circuit on account of

Two 110-V light bulbs, one "25" and the other "100W", are connected in series to a 110 V source. Then, which of the following statement us correct with regard to the above sentence?

The units of motional emf are:

Rapid stopping of a motor by momentarily connecting the motor in reverse direction is called

Who is the current IIEE President?

The per-phase line loss in a 40 km long transmission line is not to exceed 60 kW while it is delivering 100 A per phase. If the resistivity of the conductor material is 1.72 x 10-⁸ ohm-meter, determine the required conductor diameter.

Given the following set of equations: 2V1 + V2 = 5; -V1 + 3V2 + 2V3 = 1; and -V1 + 2V3 = 3

The units of magnetic dipole moment are ___

To reverse the direction of rotation of a three-phase induction motor, it is necessary to

A symmetrical positive-sequence four-bus z matrix with z11=j0.27, z12=j0.24, z13=j0.17, z14=j0.20, z22=j0.29, z23=j0.20, z24=j0.24, z34=j0.26, and z44=j0.38, all in p.u, what is the three-phase fault at bus 3?

A 69 kV three-phase transposed line is composed of one ACSR 336,400 cmil, 26/7 Linnet conductor per phase with a horizontal configuration of D12 = 5 ft, D23 = 5 ft, and D13 = 10 ft. The conductors have a diameter of 0.721 inch and a GMR of 0.0243 ft. Find the inductance per phase per kilometer of the line.

In a transmission line of negligible resistance, the surge impedance will be:

What is the actual voltage of the high-leg (middle) for the three-phase, four-wire delta grounded system 240/120 V secondary voltage?

For which of the following sinusoids, the rms value and mean value is the same?

Which of the following is not a Distribution Reliability Index?

In how many years will the energy consumption of the Philippines be quadrupled at 6.9% annual growth rate?

A certain amount of fuel contains 17 x 1010 BTU of energy. What is the corresponding energy in gigacalories?

A 3-phase 440 V, 50 Hz induction motor has 4% slip. The frequency of rotor current will be:

A 10-turn ideal solenoid has an inductance of 4.0 mH. To generate an emf of 2.0 V the current shoul change at a rate of:

An act to ensure and accelerate the total electrification of the Philippines, also known as the EPIRA law of 2001.

Which of the following transformer winding connection is MOST suitable for unbalance load?

The main purpose of performing open circuit test at rated voltage is to measure?

A magnet moves inside a coil. Which of the following factors can affect the emf induced in the coil? I. The speed at which the magnet moves II. The magnetic field of the magnet III. The number of turns in the coil

A 10-ohm inductive resistor is connected in series with an unknown capacitance. At 60 Hz the impedance of the circuit is 10 + j11.72. At 30 Hz the impedance of the circuit is 10 - j5. What is the value of L in millihenrys?

Tall growing plants refer to plants, vines and other plant species which grow or have potential to grow more than ___ meters in height from the ground.

What is the equivalent resistance of this resistor having this color RED-RED-ORANGE-SILVER