Current has unit of ___.

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

An initially uncharged capacitor C is connected in series with resistor R. This combination is then connected to a battery of emf V0. Sufficient time elapses so that a steady state is reached. Which of the following statements is NOT true?

A three-phase wye connected 20MW load of the pf 0.866 lagging is to be supplied by a transmission line is 138kV. It is desired that the line losses not exceed 5 percent of the load. If the per phase resistance of the line is 0.7 ohm, what is the maximum length of the line?

An LC circuit has an oscillation frequency of 10^5 Hz. If C = 0.1 uF, then L must be about:

Which dc motor cannot be used without a load connected to it?

The electric motor generally used in household food mixers.

Two wattmeters can be used to measure 3 phase power of a

What is the IEEE number the device name AC TIME Over Current Relay?

Which one does not belong to the technical performance standards of Philippine Distribution Code?

A transformer has a reactance of 0.04 pu. If the secondary of the transformer is short circuited with nominal voltage applied to the primary, the symmetrical short circuit current will be ___.

Capacitor C1 and C2 are connected in series. The equivalent capacitance is given by ___.

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 D12 = 5 ft, D = 5 ft, and D13 = 10 ft. The conductors have a diameter of 0.721 inch and a GMR of 0.0243ft. Find the inductance per phase per kilometer of the line.

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

A 15-ohm resistor is connected in parallel with a series combination of resistors of 8 and 12 ohms. If the voltage drop across the 8-ohm resistor is 48 V, what is the total current in A?

In a series circuit, the current is ___.

In DC generators, lap winding is used for ___ voltage, ___ current.

What is the relationship between the line current, I1, and the coil current, Ic, in a balanced delta system?

In PEC, what is the allowable voltage drop in feeder supplying lighting?

For continuous load, the maximum current is expected to continue for ___.

An induction motor draws 50 kW at a 0.60 lagging power factor from a 480V 60 Hz source. What parallel capacitor will increase the overall power factor to 0.90 lagging?

A 345-kV transmission line has a series impedance of 4 + 160 Q and a shunt admittance of j2 x 10 S. Using 100 MVA and the line voltage as base values, calculate the per-unit admittance of the line.

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

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

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

A single -phase transformer 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?

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

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 milli-henrys?

The primary of a 3:1 step-up transformer is 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 is connected directly to the source it will dissipate a power of

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

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 rice mill will be served by two units ilof 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 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.

Two single phase transformers are connected in open-delta supplying three phase load 150kVA 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?

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.

Which is NOT a characteristic of an ideal transformer?

A charged capacitor is being discharged through a resistor. At the end of one time constant, the charge has reduced by (1-1/e) = 63% of its initial value. At the end of two-time constants, the charge has been reduced by what percent of its initial value?

A transformer is rated 120-V/115-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 120 V: What will be the voltage in volts output at 50 Hz?

A certain amount of fuel contains 17x10^10 VTU of energy. What is the corresponding energy in Gigacalories?

Which is the core losses are negligible during a short-circuit test conducted on transformer?

A generator delivers a load through a pair or wires, each of which has a resistance of 0.06 ohms. If the load voltage and power are 120V and 4.8kW respectively, what is the power loss in the line wires?

A 15 ohms resistor is connected in parallel with a series combination of resistors of 8 and 12 ohms. If the voltage drops across the 8-ohm resistor is 48V, what is the total voltage applied?

A 69-kV, three-phase short transmission line is 16 km long. The line has a per phase series impedance of 0.125 + j0.4375 Ω per km. Determine the sending end voltage, voltage regulation, the sending end power, and the transmission efficiency when the line delivers 70 MVA, 0.8 lagging power factor at 64 kV.