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The most contributing factor to core losses in Transformers is the material on which they are wound. Transformers wound on iron cores are roughly 75% efficient but they can transfer large amounts of power at low frequency. Transformers wound on ferrite are typically better then 90% efficient but can't be used to transfer the same amount of power unless the frequency is increased. Switch mode power supplies do this.
After that, the voltage, impedance and current are all related. If you increase the current (by increasing the voltage) there are more losses because the magnetic field strength is not directly proportional to the current. The impedance remains the same for the same number of turns. Transformers are wound to the best compromise between efficiency and transfer capability. If you try to increase the voltage too much, the core will saturate and behave like a straight piece of wire.
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What is the principle of operation of a ballast?
Older ballasts with an iron core are basically an autotransformer. They transform voltage to a higher voltage with a single winding. Electronic transformers increase voltage with capacitors and diodes.
How do you reduce core losses?
There are various measures that can be taken to reduce core losses. Lamination of the transformer core is believed to reduce core losses significantly.
What are losses of transformer?
Core loss is one of the many fixed losses in a transformer. This means that no matter the loading of the transformer there this loss would be fixed unlike copper loss which depends on the loading of the transformer.
Why in short circuit test iron loss is very less?
In short circuit test very low voltage at primary approx 5 % of the rated voltage is given and secondary is short circuited by an ammeter. Due to low voltage very low flux is developed in core of the transformer and due to that iron losses are very low which can be neglected. By Rizwan: actually it is operated at (10-15)% of the rated voltage and as you know n case of low voltage low magnetic flux is produced and then there will be low magnetic field density(B). and we know hysteresis and eddy current losses depend on (B).as in case of : hysteresis depends on B^1.2 and eddy current depends on B^2 So if B is low then both losses(collectively called constant losses) will be very very low.
Why size of hv transformer is small?
Most people would agree that hv transformers, if that means transformers for over 1000 v, are never small. The size of a transformer is determined by physical limits. The iron-based magnetic core of a transformer is a material with a limit to the permitted flux-density allowed if losses are to be kept to a reasonable level. Therefore the core size is determined by the maximum magnetic flux required, whch in turn sets the volts-per-turn figure for the windings. The current in the windings is set by the size of wire used, which depends on the number of turns required. A large core allows fewer turns for a given voltage, therfore thicker wire can be used. Therefore a larger core allows thicker wire and more current. Thus the size of a transformer is set by its power-handling requirement. HV transformers are increased in size by the need to maintain adequate insulation on the high-voltage windings.
Distribution transformer design for which?
Distribution transformers are used on distribution side not transmission side. Core losses or Iron losses ( Hysteresis and eddy current losses ) are proportional to the square of the voltage. Copper losses are proportional to the square of the current. Distribution side voltage is less compared to the transmission side. core losses are constant irrespective of the load, but copper losses varies with the load. Transmission side transformers are not usually stopped from working by the operator frequently, they continued to work throughout the year until and unless if there is a problem and also they almost have constant load. So they are going to have more core losses. So their core is designed in order to get less core losses. Any way the copper losses will be less since the current is less because voltage is more. Distribution side transformers are having more load fluctuations and more stoppages.Their voltage is low so they will have less core losses, no need to design a better core, but distribution side current is more so copper losses are more, so distribution side transformers are designed to have less winding resistance, so that the copper losses are low.
Are transformers 100 percent efficient?
No because it will lose electron by core losses and winding losses
What is hysteresis loss in transformers?
Hysterisis losses are the losses which are taking place in the iron or steel core due to reversal of magnetisation of steel core.
Why are rotor core losses fixed?
Its not only about rotor, Core losses of every machine which has core are fixed and only vary with Voltage variation.
How many types of losses in transformer?
Basically two types: 1. Copper losses:- when the transformer is loaded, current flows in primary and secondary winding, there is loss of electrical energy due to the resistance of the primary winding, and secondary winding and they are called variable losses. These losses depend upon the loading conditions of the transformers. Therefore, these losses are also called as variable losses. 2. Iron losses or core losses:-The losses that occur in the core are known as core losses or iron losses. Two types of iron losses are: > eddy current loss > Hysteresis loss.
Why core losses are always fixed in transformer?
Core losses are losses in the magnetic system of the transformer, such as eddy currents in the core, hysteresis losses, etc. Because of this, the losses are constant, regardless of load, assuming voltage and frequency stay fixed.
What is the principle of operation of a ballast?
Older ballasts with an iron core are basically an autotransformer. They transform voltage to a higher voltage with a single winding. Electronic transformers increase voltage with capacitors and diodes.
What is Core in a Transformers?
It steps down voltage by moving the iron core spacing. Mostly using on high current welding transformer. Easy to achieve changing output voltageand does not need to use high power selector to switch voltage
What happens when a transformer is operated at no load with high voltage?
It depends on how much voltage you have applied. If you apply rated voltage nothing happens only core losses will be there on the transformer nothing will happen apart from that. If you go on increase the voltage core losses will increase and transformer will get heated up. After attaining the breakdown voltage of insulation, insulation in the primary and secondary will fail and the coils will get short circuited then the coils will burn.
How do wall transformers work?
Just like any other transformer - voltage is applied to one winding, which induces a magnetic field in the transformer core, which induces a voltage on the other winding.
Why are the core of transformers manufactured from a laminated plate?
If the transformer had a solid core it would build up eddy currents within the core possibly making the core itself rise in voltage. The laminations break up these eddy current circuits and prevent this.
What is the effect of operating a transformer on its rated frequency and at a higher voltage with no load current -hysteresis losses or eddy current losses?
A transformer is normally designed to work at a definite peak flux density in the magnetic core, which implies a fixed number of volts per turn (or turns per volt) for its windings, and this set by the cross-section area of the core. The peak flux density is a property of the core material, and this is taken into account by the transformer designer. When the transformer is operated at a higher voltage, the hysteresis loss in the core is higher, and if the flux density is higher than normal it means that the core losses increase quickly as the voltage is raised. So the no-load losses can be substantially higher, but a 20% increase in voltage can be tolerated for short periods. An exception to the above applies to European transformers designed for 50 Hz when used in North America on a 60 Hz supply. The 20% increase in frequency causes a 20% reduction in the flux density in the magnetic core, which means that the transformer can be used at a 20% higher voltage while running at the original peak flux density, and its power rating is 20% higher.
