A 230 V/460 V single-phase transformer operating at 20 A and unity power factor has primary referred

A 230 V/460 V single-phase transformer operating at 20 A and unity power factor has primary referred resistance of 0.2 Ω and reactance of 0.5 Ω. The approximate primary induced emf is

(A) 216 V (B) 226 V (C) 234 V (D) 236 V
by

1 Answer

Answer :

A 230 V/460 V single-phase transformer operating at 20 A and unity power factor has primary referred resistance of 0.2 Ω and reactance of 0.5 Ω. The approximate primary induced emf is 226 V

by

Related questions

In a 230 V, 50 Hz single-phase SCR bridge converter operating at a firing delay angle, α and with large R-L load,

Description : In a 230 V, 50 Hz single-phase SCR bridge converter operating at a firing delay angle, α and with large R-L load, the input source current is (A) sinusoidal current (B) constant dc current (C) continuous rectangular pulses (D) alternating rectangular pulses

Last Answer : In a 230 V, 50 Hz single-phase SCR bridge converter operating at a firing delay angle, α and with large R-L load, the input source current is alternating rectangular pulses

In a single-phase induction motor, the operating direction is determined by the ________

Description : In a single-phase induction motor, the operating direction is determined by the ________ A) Rotor B) Stator C) Starting circuit D) None of these

Last Answer : In a single-phase induction motor, the operating direction is determined by the Starting circuit

The no-load speed of a single-phase SCR bridge converter fed separately excited dc motor operating at a

Description : The no-load speed of a single-phase SCR bridge converter fed separately excited dc motor operating at a firing delay angle, α and flux, Φ (A) directly proportional to α and Φ (B) ... proportional to α and inversely proportional to Φ (D) directly proportional to Φ and inversely proportional to α

Last Answer : The no-load speed of a single-phase SCR bridge converter fed separately excited dc motor operating at a firing delay angle, α and flux, Φ directly proportional to α and inversely proportional to Φ

In a single-phase transformer, the magnetizing current is

Description : In a single-phase transformer, the magnetizing current is (A) in phase with the no-load current (B) in quadrature with the no-load current (C) the product of no-load current and power factor (D) in phase with the flux in the core

Last Answer : In a single-phase transformer, the magnetizing current is in phase with the flux in the core

What is the power factor when a single phase watt meter operating on 200 V and 5 A for 5 hours makes 2016

Description : What is the power factor when a single phase watt meter operating on 200 V and 5 A for 5 hours makes 2016 revolutions and the meter constant in revolution is 420? A) 0.04 B) 1.04 C) 0.96 D) None of these

Last Answer : What is the power factor when a single phase watt meter operating on 200 V and 5 A for 5 hours makes 2016 revolutions and the meter constant in revolution is 420? A) 0.04 B) 1.04 C) 0.96 D) None of these

The operating point of a protective current transformer is near the

Description : The operating point of a protective current transformer is near the

Last Answer : The operating point of a protective current transformer is near the Ankle point

The secondary of a current transformer is always short-circuited under operating conditions because it?

Description : The secondary of a current transformer is always short-circuited under operating conditions because it?

Last Answer : The secondary of a current transformer is always short-circuited under operating conditions because it avoids core saturation and high voltage induction.

For a transformer, operating at constant load current, maximum efficiency will occur at?

Description : For a transformer, operating at constant load current, maximum efficiency will occur at?

Last Answer : For a transformer, operating at constant load current, maximum efficiency will occur at unity power factor.

A 230 V, 50 Hz phase controlled single-phase full-controlled SCR bridge converter draws 15 A constant dc

Description : A 230 V, 50 Hz phase controlled single-phase full-controlled SCR bridge converter draws 15 A constant dc current. If the source inductance is 3 mH, the drop in dc output voltage is (A) 4.5 V (B) 6.75 V (C) 9 V (D) 13.5 V

Last Answer : A 230 V, 50 Hz phase controlled single-phase full-controlled SCR bridge converter draws 15 A constant dc current. If the source inductance is 3 mH, the drop in dc output voltage is 9 V

The power factor of a single-phase induction motor is usually?

Last Answer : The power factor of a single-phase induction motor is usually lagging.

An AC supply of 230 V is applied to a half-wave rectifier circuit through a transformer having primary to

Description :  An AC supply of 230 V is applied to a half-wave rectifier circuit through a transformer having primary to secondary turn’s ratio 12:1. The peak inverse voltage is A) 8.62 V B) 12 V C) 19.17 V D) 27.11 V 

Last Answer :  An AC supply of 230 V is applied to a half-wave rectifier circuit through a transformer having primary to secondary turn’s ratio 12:1. The peak inverse voltage is A) 8.62 V B) 12 V C) 19.17 V D) 27.11 V 

Single-phase mid-point controlled rectifier with RL load

Description : Single-phase mid-point controlled rectifier with RL load

Last Answer : Single-phase mid-point controlled rectifier with RL load : The circuit configuration of single-phase midpoint controlled rectifier is shown in the figure. During positive half-cycle of ... some part of next positive half-cycle of voltage with reversed polarity can appear across load.

Single-phase Midpoint controlled rectifier with Resistive load

Description : Single-phase Midpoint controlled rectifier with Resistive load

Last Answer : Single-phase Midpoint controlled rectifier with Resistive load:  1) During positive half cycle of AC supply, a is positive with respect to b , this makes T1 forward biased and T2 is reverse ... voltage reverses the polarity and T2 is turned off. The operation is as shown in waveforms.

When the firing angle a of a single-phase, fully controlled rectifier feeding constant direct current into a

Description : When the firing angle a of a single-phase, fully controlled rectifier feeding constant direct current into a load is 30°, the displacement power factor of the rectifier is

Last Answer : When the firing angle a of a single-phase, fully controlled rectifier feeding constant direct current into a load is 30°, the displacement power factor of the rectifier is √3/2

An additional condition for parallel operation of three-phase transformers over single-phase transformers is that

Description : An additional condition for parallel operation of three-phase transformers over single-phase transformers is that

Last Answer : An additional condition for parallel operation of three-phase transformers over single-phase transformers is that the transformers should belong to the same vector group

The sequence components of current of a single-phase load connected to a 3-phase system are

Description : The sequence components of current of a single-phase load connected to a 3-phase system are (A) equal positive and negative sequence components (B) equal positive, negative and zero sequence components (C) vector sum of sequence currents is zero (D) algebraic sum of sequence currents is zero

Last Answer : The sequence components of current of a single-phase load connected to a 3-phase system are equal positive, negative and zero sequence components

In a single-phase induction motor when the rotor is stationary and voltage is applied to the stator, then

Description : In a single-phase induction motor when the rotor is stationary and voltage is applied to the stator, then (A) the flux is constant (B) the flux first decreases and then increases in ... increases and decreases in the opposite direction with the same magnitude (D) current flows through the rotor

Last Answer : In a single-phase induction motor when the rotor is stationary and voltage is applied to the stator, then the flux first decreases and then increases in the same direction

The starting winding of a single-phase motor is placed in?

Last Answer : The starting winding of a single-phase motor is placed in stator.

The capacitors used in single-phase capacitor motors have no?

Last Answer : The capacitors used in single-phase capacitor motors have no polarity marking.

If starting winding of a single-phase induction motor is left in the circuit, it will?

Last Answer : If starting winding of a single-phase induction motor is left in the circuit, it will draw excessive current and overheat.

A single-phase induction motor is?

Last Answer : A single-phase induction motor is inherently non-self-starting with low torque.

In a capacitor start single-phase motor, when capacitor is replaced by a resistance?

Last Answer : In a capacitor start single-phase motor, when capacitor is replaced by a resistance motor will continue to run in same direction.

In a shaded pole single-phase motor, the revolving field is produced by the use of?

Last Answer : In a shaded pole single-phase motor, the revolving field is produced by the use of shading coils.

The rotor developed by a single-phase motor at starting is?

Last Answer : The rotor developed by a single-phase motor at starting is zero.

In capacitor start single-phase motors?

Last Answer : In capacitor start single-phase motors current in the starting winding leads the voltage.

If the capacitor of a single-phase motor is short-circuited?

Last Answer : If the capacitor of a single-phase motor is short-circuited the motor will not start.

Transistor operating configurations

Description : Transistor operating configurations

Last Answer : Transistor operating configurations

Draw construction of Megger and write operating principle of it.

Description : Draw construction of Megger and write operating principle of it.

Last Answer : Megger:  Working: Two coils the current coil and pressure coil are mounted at an angle on the same spindle and form the part of the moving system. These coils are connected to a small hand driven ... . When the instrument is not working the pointer may rest at any position on the dial.

Explain the operating principle of LASER and list applications of LASER diode.

Description : Explain the operating principle of LASER and list applications of LASER diode.

Last Answer : A basic construction of Laser diode is as shown . A PN junction is formed by two layers of doped gallium arsenide. There is highly reflective surface at one end of PN junction and ... 6. laser scanning and light beam illumination. 7. Military applications 8. Medical surgery 9.Diamond cutting

A minimum clearance of 6.3 m to ground is required for overhead lines when operating voltages are :

Description : A minimum clearance of 6.3 m to ground is required for overhead lines when operating voltages are :  (A) less than 66 kV (B) lie between 66 kV and 110 kV (C) more than 165 kV (D) lie between 110 kV and 165 kV

Last Answer : A minimum clearance of 6.3 m to ground is required for overhead lines when operating voltages are : lie between 66 kV and 110 kV

51 A transformer has negative voltage regulation when its load power factor is A. Zero B. Unity C. Leading D. Lagging

Description : 51 A transformer has negative voltage regulation when its load power factor is A. Zero B. Unity C. Leading D. Lagging

Last Answer : C. leading

Two synchronous generators operating in parallel supply a common load of 2.5 MW. The frequency-power

Description : Two synchronous generators operating in parallel supply a common load of 2.5 MW. The frequency-power characteristics have a common slope of 1 MW/Hz and the no-load frequencies of the generators are 51.5 Hz and 51.0 Hz, ... system frequency is (A) 50 Hz (B) 51 Hz (C) 51.25 Hz (D) 51.5 Hz

Last Answer : Two synchronous generators operating in parallel supply a common load of 2.5 MW. The frequency-power characteristics have a common slope of 1 MW/Hz and the no-load frequencies of the generators are 51.5 Hz and 51.0 Hz, respectively. Then the system frequency is 50 Hz

Annual operating expenditure of a power plant consists of?

Last Answer : Annual operating expenditure of a power plant consists of fixed charges, semi-fixed charges, running charges.

Operating frequency of power MOSFET is higher than that of power BJT. Justify the statement.

Description : Operating frequency of power MOSFET is higher than that of power BJT. Justify the statement.

Last Answer : Power MOSFET have high turning on and turning off capability high switching speed of MOSFET is due to the high rate of change of drain voltage. The switching losses of power MOSFET ... lower frequency. Hence, operating frequency of power MOSFET is higher than that of power BJT.

How to Uninstall an Operating System ?

Description : How to Uninstall an Operating System ?

Last Answer : How to Uninstall an Operating System Even the most stable operating systems can crash, and suffer from irreparable damage that you may need to uninstall and reinstall them. Some users, though, may like to ... , you can easily remove the old, damaged operating system, and replace it with a new one.

operating principle of PUT.

Description :  operating principle of PUT.

Last Answer : Constructional diagram & Operating principle of PUT:  The PUT is a PNPN device similar to SCR, but its operation is similar to the UJT. The PUT behave like a UJT whose trigger voltage VP can be set ... low resistance and VAK ≈ 1V). The PUT is also referred to as a complementary SCR (CSCR). 

The command line interpreter that enables the users to interact with operating system is called the

Description : The command line interpreter that enables the users to interact with operating system is called the A) Window B) Shell C) Process D) Kernel 

Last Answer : The command line interpreter that enables the users to interact with operating system is called the Shell 

The operating time of instantaneous relay is

Description : The operating time of instantaneous relay is

Last Answer : The operating time of instantaneous relay is 0.1 sec

Operating torques in analogue instruments are?

Last Answer : Operating torques in analogue instruments are deflecting, control and damping.

The operating voltage of a meggar is about?

Last Answer : The operating voltage of a meggar is about 100 V.

To limit the operating temperature an electrical machine should have proper?

Last Answer : To limit the operating temperature an electrical machine should have proper current rating.

The operating speed of a synchronous motor can be changed to new fixed value by?

Last Answer : The operating speed of a synchronous motor can be changed to new fixed value by changing frequency.

The relay operating speed depends upon?

Last Answer : The relay operating speed depends upon the spring tension, the rate of flux built up, armature core air gap.

what are the three operating regions of BJT?

Last Answer : Active , Saturation , Cut-off region of operations in BJT.

50 The equivalent resistance of the primary of the transformer having K = 5, R1 = 0.1 ohm when referred to secondary becomes .....ohm A. 0.5 B. 0.02 C. 0.004 D. 2.5

Description : 50 The equivalent resistance of the primary of the transformer having K = 5, R1 = 0.1 ohm when referred to secondary becomes .....ohm A. 0.5 B. 0.02 C. 0.004 D. 2.5

Last Answer : A. 0.5

One single-phase energy meter operating on 230 V and 5 A for 5 hours makes 1940 revolutions. Meter...

Description : One single-phase energy meter operating on 230 V and 5 A for 5 hours makes 1940 revolutions. Meter constant is 400 rev/kWh. The power factor of the load is

Last Answer : One single-phase energy meter operating on 230 V and 5 A for 5 hours makes 1940 revolutions. Meter constant is 400 rev/kWh. The power factor of the load is 0.8

A single-phase, 230 V, 50 Hz ac mains fed step down transformer (4:1) is supplying power to a half-wave

Description : A single-phase, 230 V, 50 Hz ac mains fed step down transformer (4:1) is supplying power to a half-wave uncontrolled ac-dc converter used for charging a battery (12 V dc) with the series current limiting resistor being 19.04 Ohm. The charging current is  (A) 2.43 A (B) 1.65 A (C) 1.22 A (D) 1.0 A

Last Answer : A single-phase, 230 V, 50 Hz ac mains fed step down transformer (4:1) is supplying power to a half-wave uncontrolled ac-dc converter used for charging a battery (12 V dc) with the series current limiting resistor being 19.04 Ohm. The charging current is 1.0 A

A three-phase synchronous motor has a terminal voltage of 460 V and a terminal current of 120 A at a power factor of 0.95 lagging, synchronous reactance of 1.68 ohm and the field current is 47 A. The field to armature mutual inductance of the synchronous motor is _____________.

Description : A three-phase synchronous motor has a terminal voltage of 460 V and a terminal current of 120 A at a power factor of 0.95 lagging, synchronous reactance of 1.68 ohm and the field current is 47 A. The field to armature mutual ... _____________.      (a). 20mH   (b). 16mH   (c). 24mH   (d). 22mH

Last Answer : 22

6 In a two winding transformer, the primary and secondary induced emf E1 & E2 are always A. equal in magnitude B. anti phase with each other C. in phase with each other D. determined by load on transformer secondary

Description : 6 In a two winding transformer, the primary and secondary induced emf E1 & E2 are always A. equal in magnitude B. anti phase with each other C. in phase with each other D. determined by load on transformer secondary

Last Answer : C. In phase with each other

For a cyclone of diameter 0.2 m with a tangential velocity of 15 m/s at the wall, the separation factor is (A) 2250 (B) 1125(C) 460 (D) 230

Description : For a cyclone of diameter 0.2 m with a tangential velocity of 15 m/s at the wall, the separation factor is (A) 2250 (B) 1125 (C) 460 (D) 230

Last Answer : (D) 230