Why skin effect absent in dc system?

Why skin effect for a conductor is not applicable for DC?

As we know that skin effect occures in ac system.skin effect dependes on frequncy.In case of dc syastem frequncy is zero.So skin effect for conductor is not applicable for dc.

Skin effect related to ac and DC?

IT IS RELATED TO AC ONLY BKZ SKIN EFFECT DEPENDS FREQUENCY ONLY WHERE IS IN DC NO FREQUENCY

What is meant by skin effect?

The skin effect occurs in conductors carrying alternating currents, where the tendency is for the current to flow towards the surface of the conductor. The effect increases with frequency. At radio frequencies, the skin effect is so pronounced, that there is little point in using solid conductors, so tubes are used instead.The skin effect is responsible for the so-called 'AC resistance'. This is because the skin effect acts to reduce the effective cross-sectional area of a conductor, thus increasing its resistance compared to when a DC current passes through the conductor.

What were the advantages disadvantages of power DC?

Currently, the transmission of electrical power from bulk power generators all the way to household, commercial and industrial consumers is made through high voltage alternating current (AC) transmission and distribution systems, and through a series of voltage transformations to reduce losses and minimize cost. Voltage levels used are of standard values. AC system is used in the transmission of bulk power, instead of DC (Direct Current), because of its ability to transform voltage to various levels by using a transformer. The voltage transformation follows the faradays Law which states;The emf induced in a circuit is directly proportional to the time rate of change of magnetic flux through the circuit. Note that, at higher voltage, the current was reduced thus line losses was also reduced. Ability to transform voltage and to flow power in two opposite directions (bidirectional) are the only advantages of AC system over DC system. DC transmission system on the other hand has more advantages over AC transmission system: 1. Reactance. DC system does not introduce a reactance in the line. 2. Resistance DC system reduces the amount of resistance in the line. 3. Power In DC system, the power is just the real component. 4. Frequency In DC system, the frequency is zero, thus no frequency variation to monitor. Connection will not also require synchronization. 5. Susceptance DC system does not introduce susceptance in the line thus removing the effect of charging current. 6. Analysis Analysis of AC system always involved complex numbers, while DC is only a real number, thus simplifying the analysis. 7.Number of conductors. A DC system requires only two conductrs as compare to three for ac system. 8.Absence of inductance. A DC system has no inductance as a result the voltage drop in DC system is less than that of AC system for same load and sending end voltages and hence a better voltage regulation. 9.NO skin effect. A DC system has no skin effect so we can utilize entire cross section area of line conductor. 10.Less insulation require. A DC system require less insulation than an AC system because of less potential stress for same working voltage. 11.absence of capacitance. Absence of capacitance in DC system leads to less power loss because there will not be charging and discharging of capacitance. If DC system has the ability to transform voltage into various levels, efficiently, the DC transmission system will the more efficient, stable, easy to monitor, and most importantly, easy to analyze than AC system. Currently, the transformation of DC voltage into another level involves 3 steps; 1. AC to DC Rectification 2. AC to AC transformation, and 3. DC to AC Conversion If compared to AC system voltage transformation, steps 1 and 3 are the only added steps. Unfortunately, these steps incur additional heavy losses. However, modern technology converter/inverter has attempted to reduce the amount of this loss. A 1000 MW, 230 KV AC - 450 KV DC/ 450 KV DC - 230 kV AC converter/inverter, for example, has a combine power loss of around 1.6 %. The use of DC system in the transmission of power will be more economical if the price from its benefits is higher that the cost incurred from the addition of rectifier and converter.

What is Skin effect in transmission lines?

when a conductor is carrying a steady DC current,it is uniformly distributed over the whole cross section of the conductor. however, an alternating current flowing through the conductor does not distribute uniformly . Rather it has a tendency to concentrate near the surface of the conductor. This is known as skin effect

What is demagnetising effect of DC generator?

demagnetising effect of dc generator is to reduce main field flux there by reduction in generated voltage.

Why less loss occurs when you use DC supply than AC supply?

There are less loss occurs when we use DC supply than AC supply, because the frequency is zero in DC, so no Inductance & Capacitance exists.And there is no skin effect in the DC systems, so there is low resistance as compared to AC systems.Rac = 1.25*Rdcfrom Arun Kumar SRR

What is the difference between ac Hall effect and dc Hall effect?

The AC Hall effect is used to measure the sign and magnitude of an alternating magnetic field, whereas the DC Hall effect is used to measure the sign and magnitude of a steady magnetic field. In AC Hall effect, the magnetic field changes direction periodically, while in DC Hall effect, the magnetic field is constant.

What effect does altitude have on a DC motor?

very little

Why dc supply is being used in studying the effect of temperature on the field winding resistance of a dc motor?

Because tests on a dc motor are always done using dc.

Why dc supply cannot be given to transmission lines?

We can use DC too for the transmission system. Refer HVDC transmission system.

What skin colors can you see in Washington D.C.?

Washington DC as the nation's capitol is home to embassies and consulates from countries around the globe. In addition a number of global entities call Washington DC home. Washington DC is truly multi-ethnic and you can find representatives from all nationalities, all skin colors in DC.