# In which type of AC to DC converter efficiency is higher :

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In which type of AC to DC converter efficiency is higher :

In which type of AC to DC converter efficiency is higher : solid state rectifier

## Related questions

A single-phase fully controlled thyristor bridge ac-dc converter is operating at a firing angle of 25o and an overlap angle of 10o with constant dc output current of 20 A. The fundamental power factor (displacement factor) at input ac mains is  (A) 0.78 (B) 0.827 (C) 0.866 (D) 0.9

When The dc converter in figure shown has a resistance load of R = 10 Ω and the input voltage is Vs 220 V the converter switch remains on, its voltage drop is Vo -2 V. The chopping frequency is fI K sW Vs If the duty cycle is 50%, determine: (a) the average output voltage V (b) the RMS output voltage Vo (c) the converter efficiency (d) the effective input resistance of the converter

A converter which can operate in both 3 pulse and 6 pulse mode is a  (A) 1 phase full converter (B) 3 phase half wave converter (C) 3 phase semi converter (D) 3 phase full converter.

A 3-phase fully controlled bridge converter with free wheeling diode is fed from 400 V, 50 Hz AC source and is operating at a firing angle of 60o. The load current is assumed constant at 10 A due to high load inductance. The input displacement factor (IDF) and the input power factor (IPF) of the converter will be  (A) IDF IPF = = 0.867; 0.828 (B) IDF IPF = = 0.867; 0.552 (C) IDF IPF = = 0.5; 0.478 (D) IDF IPF = = 0.5; 0.318

Which is the fastest type of analogue to digital converter?

In practice, a current source inverter consists of an AC/ DC converter with a large inductance ‘L’ in the output. This inductance maintains a ……… …………through the switching devices over short interval of time. A) constant current B) constant voltage C) constant power D) none of the (A), (B), (C)

A three-phase, 440 V, 50 Hz ac mains fed thyristor bridge is feeding a 440 V dc, 15 kW, 1500 rpm separately excited dc motor with a ripple free continuous current in the dc link under all operating conditions, Neglecting the losses, the power factor of the ac mains at half the rated speed is  (A) 0.354 (B) 0.372 (C) 0.90 (D) 0.955

Which type of timing violation will occur, If a digital IC is operated at clock frequency which is higher than its specified maximum clock frequency?  A) Hold violation B) Setup Violation C) Propagation delay D) All of above

Regenerative breaking of ac-dc converter fed dc motor is possible when firing delay angle of SCRs is (A) 30° (B) 60° (C ) 90° (D) 120°

A single phase fully controlled thyristor bridge ac -dc converter is operating at a firing angle of 25 degree and an overlap angle 10 degree with constant dc output current of 20A. The fundamental power factor (displacement factor) at input ac mains is : (A) 0.78 (B) 0.827 (C) 0.866 (0) 0.9

Which method is not used for conversion of AC to DC? A. Motor-generator set B. Rotary converter C. Metal rectifiers D. Dynamometers

A solar cell of 350 V is feeding power to an ac supply of 440 V, 50 Hz through a 3-phase fully controlled bridge converter. A large inductance is connected in the dc circuit to maintain the dc current at 20 A. If the solar cell resistance is 0.5 Ohm ,then each thyristor will be reverse biased for a period of  (A) 125o (B) 120o (C) 60o (D) 55o

The number of comparators required in a 3-bit comparator type analog to digital converter is  A) 2 B) 3 C) 7 D) 8

A three-phase, fully controlled thyristor bridge converter is used as line commutated inverter to feed 50 kW power 420 V dc to a three-phase, 415 V(line), 50 Hz ac mains. Consider dc link current to be constant. The rms current of the thyristor is  (A) 119.05 A (B) 79.37 A (C) 68.73 A (D) 39.68 A

Which type of starter is used to start the DC motor?

A DC reactor is connected in series with each pole of a converter station in order to: A) prevent commutation failures in the inverter B) supply reactive power to the converter C) improve system stability D) increase the power transfer capability

For an existing ac transmission line, the string efficiency is 80%, if dc voltage is supplied for the same setup, the string efficiency will be?

Which of the following device converts DC to AC?  A) Rectifier B) Boost converter C) Transformer D) Inverter

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

The ripple content of load current of a converter feeding RL load is decided by  A) Load resistance alone B) Load inductance alone C) Both load resistance and load inductance D) Neither resistance nor inductance

A freewheeling diode in a phase controlled converter  A) Deceases the possibility of discontinuous conduction in the load B) Increases the possibility of discontinuous conduction in the load C) Reduces the power factor and causes over voltages D) Causes over voltages

A single phase full-wave half-controlled bridge converter feeds an inductive load. The two SCRs in the converter are connected to a common DC bus. The converter has to have a freewheeling diode.  (A) because the converter inherently does not provide for free-wheeling (B) because the converter does not provide for free-wheeling for high ... the AC supply (D) or else if a gate pulse to one of the SCRs is missed, it will subsequently cause a high load current in the other SCR.

Which rectifier can convert AC to DC? A. Half wave rectifier B. Full wave rectifier C. Bridge wave rectifier D. All of these

Which device use to convert DC to AC?

Which of the following instruments is equally accurate on ac as well as dc circuits ? (a) PMMC voltmeter (b) Dynamometer wattmeter (c) Moving iron ammeter (d) Induction wattmeter

In order to reduce the harmful effects of harmonics on the AC side of a high voltage DC transmission system_____ are provided. (A) synchronous condensers (B) shunt capacitors (C) shunt filters (D) static compensators

An unshielded moving iron voltmeter is used to measure the voltage in an AC circuit. The stray DC magnetic field having a component along the axis will be  (1) unaffected (2) decreased (3) increased (4) either decreased or increased depending on the direction of the DC field

In an isolated output dc-to-dc fly back converter, the high frequency transformer used works as an inductor (a) during turn -on period of the switching device (b) during turn off period of the switching device (c) during both (d) none of these

A three phase fully controlled bridge converter is feeding a load drawing a constant and ripple free load current of 10 A at a firing angle of 30o. The approximate Total harmonic Distortion (%THD) and the rms value of fundamental component of input current will respectively be  (A) 31% and 6.8 A (B) 31% and 7.8 A (C) 66% and 6.8 A (D) 66% and 7.8 A

An AC supply of 230 V is applied to half wave rectifier circuit. A transformer turns ratio is 20 : 1. Find i) Output DC voltage (ii) Peak Inverse Voltage (PIV)

A large dc motor is required to control the speed of the blower from a 3 -phase ac source. The suitable ac to dc converter is, 3 -phase (a) Fully controlled bridge converter (b) Fully controlled bridge converter with freewheeling diode (c) Half controlled bridge converter (d) Converter pair in sequence control

Which of the following motors can run on both AC and DC? A) Universal motor B) Dual wattage motor C) Flexible motor D) All the above

which is dangerous AC or DC ?

What type of instrument is used to measure dc voltage of the order 5 volts? (A) moving iron type (B) electro-static type (C) moving coil type (D) all of these

Which of the following test is usually conducted to determine the efficiency of traction motors ? (A) Field’s test (B) Swinburne’s test (C) Hopkinson’s test (D) Retardation test.

a single phase full wave midpoint thyristor converter uses a 230/200V transformer with centre tap on the secondary side. The P.I.V per thyristor is   (A) 100V (B)141.4V (C)200V (D)282.8V

A separately excited dc motor operating in first quadrant is fed from 3-phase semi -converter free -wheeling diode is open circuited, then the motor :  (A) can be operated in first quadrant (B) can be operated in first & second quadrants (C) can be operated in first & fourth quadrants (D) cannot be operated

An amplifier which has almost same gain and input resistance of a CE amplifier but of higher bandwidth is  A) Cascode amplifier B) Cascade amplifier C) Darligton amplfier D) CC amplifier

Do you think is DC better than AC to transmit energy?

How is a thyristor used to convert AC to DC?

The use of thermocouple meters for AC measurement leads to a meterscale which is _____.

A 3 -phase, fully controlled, converter is feeding power into a DC load at a constant current of 150 A, the rms value of the current flowing through each thyristor of the converter is

Give broad classification of maintenance with meaning of each type. State the factors on which ideal maintenance of electric rolling stock is judged. Give any two means to improve any one factor of these.

Which type of protection is provided on a generator to protect against stator insulation failure? A) Differential protection B) Overcurrent relay C) Thermocouple actuated alarm D) Reverse power relay

Which type of heater is cheapest to run?

Is the power line voltage available in our homes a dc or an ac voltage?