What is meant by step-up cyclo-converters?

1 Answer

Answer :

In these converters, the output frequency is less than the supply frequency.

Related questions

Description : What is meant by step-down cyclo-converters?

Last Answer : In these converters, the output frequency is more than the supply frequency.

Description : What are the two types of cyclo-converters?

Last Answer : a. Step-up cyclo-converters b. Step-down cyclo-converters

Description : What are the types of cyclo-converters?

Last Answer : Step up cyclo-converter Step down cyclo-converter.

Description : What is step up cyclo-converter ?

Last Answer : It is the converter whose output frequency is more than the input frequency.

Description : What is step down cyclo-converter?

Last Answer : It is the converter whose output frequency is less than the input frequency.

Description : What is meant by cyclo-converter?

Last Answer : It converts input power at one frequency to output power at another frequency with one-stage conversion. Cycloconverter is also known as frequency changer.

Description : What is meant by cyclo-converter?

Last Answer : It is also known as frequency changer. It converts input power at one frequency to output power at another frequency with one stage conversion.

Description : What are the applications of cyclo-converter?

Last Answer : a. Induction heating b. Speed control of high power ac drives c. Static VAR generation d. Power supply in aircraft or ship boards

Description : What is meant by step-up and step-down chopper?

Last Answer : In a step- down chopper or Buck converter, the average output voltage is less than the input voltage. In a step- up chopper or Boost converter, the average output voltage is more than the input voltage.

Description : Write down the expression for the average output voltage for step down and step up chopper.

Last Answer : Average output voltage for step down chopper is VO= αVS. Average output voltage for step up chopper is VO= αVSx [1/ ( 1- α)].

Description : Write down the expression for average output voltage for step up chopper.

Last Answer : Average output voltage for step down chopper V0= Vs, αis the duty cycle 1- α

Description : Write down the expression for average output voltage for step down chopper.

Last Answer : Average output voltage for step down chopper V0 = αVs, αis the duty cycle

Description : What is meant by negative converter group in a cycloconverter?

Last Answer : The part of the cycloconverter circuit that permits the flow of current during negative half cycle of output current is called negative converter group.

Description : What is meant by positive converter group in a cycloconverter?

Last Answer : The part of the cycloconverter circuit that permits the flow of current during positive half cycle of output current is called positive converter group.

Description : What is meant by sequence control of ac voltage regulators?

Last Answer : It means that the stages of voltage controllers in parallel triggered in a proper sequence one after the other so as to obtain a variable output with low harmonic content.

Description : What is meant by high frequency carrier gating?

Last Answer : Thyristor is turned on by using a train of pulses from αto π. This type of signal is called as high frequency carrier gating.

Description : What is meant by PWM control?

Last Answer : In this method, a fixed dc input voltage is given to the inverter and a controlled ac output voltage is obtained by adjusting the on and off periods of the inverter components. This is the most popular method of controlling the output voltage and this method is termed as PWM control.

Description : What is meant by McMurray inverter?

Last Answer : It is an impulse commutated inverter which relies on LC circuit and an auxiliary thyristor for commutation in the load circuit.

Description : What is meant a parallel inverter?

Last Answer : An inverter in which the commutating elements are connected in parallel with the load is called a parallel inverter.

Description : What is meant a series inverter?

Last Answer : An inverter in which the commutating elements are connected in series with the load is called a series inverter.

Description : What is meant by inverter?

Last Answer : A device that converts dc power into ac power at desired output voltage and frequency is called an inverter.

Description : What is meant by load commutation?

Last Answer : In this process, the load current flowing through the thyristor either becomes zero or is transferred to another device from the conducting thyristor.

Description : What is meant by current commutation?

Last Answer : In this process, a current pulse is made to flow in the reverse direction through the conducting thyristor and when the net thyristor current becomes zero, it is turned off.

Description : What is meant by voltage commutation?

Last Answer : In this process, a charged capacitor momentarily reverse biases the conducting thyristor and turn it off.

Description : What is meant by PWM control in dc chopper?

Last Answer : In this control method, the on time Ton is varied but chopping frequency is kept constant. The width of the pulse is varied and hence this type of control is known as PulseWidth Modulation (PWM).

Description : What is meant by FM control in a dc chopper?

Last Answer : In frequency modulation control, the chopping frequency f (or the chopping period T) is varied. Here two controls are possible. a. On-time T onis kept constant b. Off period T offis kept constant.

Description : What is meant by TRC?

Last Answer : In TRC, the value of Ton/ T is varied in order to change the average output voltage.

Description : What is meant by duty-cycle?

Last Answer : Duty cycle is defined as the ratio of the on time of the chopper to the total time period of the chopper. It is denoted by α.

Description : What is meant by dc chopper?

Last Answer : A dc chopper is a high speed static switch used to obtain variable dc voltage from a constant dc voltage.

Description : What is meant by delay angle?

Last Answer : The delay angle is defined as the angle between the zero crossing of the input voltage and the instant the thyristor is fired.

Description : What is meant by phase controlled rectifier?

Last Answer : It converts fixed ac voltage into variable dc voltage.

Description : What is meant by chopper?

Last Answer : Chopper converts fixed dc voltage into variable dc voltage

Description : What is meant by four quadrant operation?

Last Answer : A motor operate in two modes-motoring and braking. In motoring, it converts electrical energy into mechanical energy, which supports its motion. In braking, it works as a generator converting ... the motion. Motor can provide motoring and braking operations for both forward and reverse directions.

Description : What is meant by Electrical Drives?

Last Answer : Answer: Systems employed for motion control are called as Drives and many employ any of the prime movers such as, diesel or petrol engines, gas or steam turbines, hydraulic motors and electric ... about the basics and every part of the electrical drive system and explain as detail as possible.

Description : What is meant by slip power?

Last Answer : The portion of air gap power, which is not converted into mechanical power, is called slip power. Slip power is nothing but multiplication of slip(s) and airgap power (Pag) Slip power = s. Pag

Description : What is meant by rotor resistance control?

Last Answer : In a slip ring induction motor, a variable resistances are connected in the rotor circuit. By controlling the rotor resistance, the motor speed can be controlled as well as increase the ... and reduce the starting current. This method of speed control is called rotor resistance control method.

Description : What is meant by plugging?

Last Answer : It is one method of braking of induction motor. When phase sequence of supply of the motor running at a speed is reversed, by interchanging connections of any two phases of stator with respect to supply terminals, operations shifts from motoring to plugging region.

Description : What is meant by dynamic braking?

Last Answer : Dynamic braking of electric motors occurs when the energy stored in the rotating mass is dissipated in an electrical resistance. This requires the motor to operate as a generator to convert this stored energy into electrical.

Description : What is meant by stator current control?

Last Answer : The three-phase induction motor speed can be controlled by stator current control. The stator current can be varied by using current source inverter.

Description : What is meant by V/F control?

Last Answer : When the frequency is reduced, the input voltage must be reduced proportionally so as to maintain constant flux. Otherwise the core will get saturated resulting in excessive iron loss and magnetizing current. This type of induction motor behaviour is similar to the working of dc series motors.

Description : What is meant by PMDC?

Last Answer : PMDC stands for Permanent Magnet DC Motor A Permanent Magnet DC Motor is similar to an ordinary dc shunt motor except that its field is provided by permanent magnets instead of salient-pole ... -earth magnets The major advantages are low noise, small size, high-efficiency, low manufacturing cost.

Description : What is meant by commutation?

Last Answer : The process of changing the direction of current flow in a particular path of the circuit. It is used to turn off the SCR.

Description : Why Generation Voltage in Power Plant is Low (11kV to 33kV) ?

Last Answer : Generally electrical power is generated at low voltages (generation voltage will be around 11 to 33kV) depending on the power output rating of the generator and transmitted to the load centers by stepping up the ... operate at 23.5 kV with line currents of about 19,000 A at 0.85 power factor.

Description : What are the different losses that occur in thyristor while operating?

Last Answer : Different losses that occur are Forward conduction losses during conduction of the thyristor Loss due to leakage current during forward and reverse blocking. Power loss at gate or Gate triggering loss. Switching losses at turn-on and turn-off.

Description : What is the relation between the gate signal and forward break over voltage (VBO)?

Last Answer : Thyristor can be triggered by increasing the forward voltage between anode and cathode, at forward break over voltage thyristor starts conducting. However this process may damage the thyristor, so thyristor ... of the gate current. Higher is the gate current lower is the forward break over voltage

Description : Why thyristor is considered as Charge controlled device?

Last Answer : During the triggering process of the thyristor from forward blocking state to forward conduction state through the gate signal, by applying the gate signal (voltage between gate and cathode) increases the ... By controlling the amount of charge we can control the turning on time of the scr.

Description : What are the different operation regions of the SCR?

Last Answer : SCR or thyristor will have three regions of operations based on the mode in which the device is connected in the circuit. Reverse blocking region: When the cathode of the thyristor is made positive with ... scr. Hence a gate signal is applied before the forward break over voltage to trigger the scr.

Description : What are the advantages of sequence control of ac voltage regulators?

Last Answer : a. System power factor is improved. b. Harmonics are reduced in the source current and the load voltage.

Description : What are the disadvantages of continuous gating signal?

Last Answer : a. More heating of the SCR gate. b. Increases the size of pulse transformer.

Description : What type of gating signal is used in single phase ac voltage controller with RL load?

Last Answer : High frequency carrier gating signal is used for single phase ac voltage controller with RL load.