What is difference between AC and DC resistance
Answer Posted / engineering.force
the dc resistance remains constant provided the external
conditions like temperature, moisture, pressure etc. do not
change. the dc resistance does not have any relation
whatsoever to the frequency as there is no frequency for the
dc supply. the current flows uniformly through the cable and
for most cases, the current density at all points is the same.
the ac resistance is frequency dependent. it do not remain
constant with variation in frequency. the self inductance
and mutual inductance of the transmission line play a role
in defining the ac resistance of the transmission line. if
frequency is increased, the resistance of the core of cable
will increase. the current density is not uniform at all
points in the conductor. also, the effective surface area of
the conductor will reduce with increase in the frequency.
this is called skin effect.
Is This Answer Correct ? | 24 Yes | 1 No |
Post New Answer View All Answers
A commercial Building is designed with 14th floor levels with indoor substation of three phase transformer with rated capacity of 1000 Kva.The transformer delivered 65% of its rated capacity at 0.67 power factor lagging.Because of low power factor, the power customer was penalized and certain cost was charged accordingly based on every point percentage lower than 85%.This situation may repeatedly happen on the succeding energy bills of power customer.The power customer is desired to improve its historical power factor of 0.67 lagging and no further penalty be impose by the local power company on the next bill. Q: Identify the appropriate solution you want to offer to Client?.Justify SCIENTIFICALLY and MATHEMATICALLY the principles behind the solution.
In EHV transmission line a neutral grounding reactor is often placed at neutral point of shunt reactors. What is the recommended protection for this neutral grounding reactor? Should I use a fast closing switch to bypass neutral grounding reactor when this protection operates?
what is the use of vcb & isolator in substation?
What is the best thing to protect the motor from running over full current. CT or O/L or pressure transducer at the given pressure rating
When color of silica gel will gets change from blue to pink from Top to bottom?
What is the difference between a verilog task and a verilog function?
What is sensitivity of a measurement?
1 Ton is equal to how many watts?
state types of reflectors in illumination engg. ???????
What is notching in dc machine?
what is EIB lighting control system? what is the advantages of this system?
what exactly commisioning work does in electrical site work... LT side?..
Why frequency changes due to load variation in power system ? i.e why when load increases frequency decreases?
how you will decide the distance between the power transformer and its fencing
what is the purpose of bypass mode in energy lighting transformer?