What happens to the power factor of a transformer when the input voltage exceeds the rated voltage? Will it increase or decrease? Give explanation.
If v=220V, I=25A, power factor=0.8, frequency=400Hz. If the motor runs for 3 hours, What is the power consumed?
Latest Answer: P=V*I*CosAA is powerfactor V is VolatageI is Current P=220*25*0.8P=4400wattsPower P is 4.4Kwatts ...
How to can calculate voltage drop in a cable?
Latest Answer: According to me this is how the voltage drop in a cable is calculated.If*SQRT(Rf Cos(phi) + Xf sin(phi)) / no. of runswhere....If is the full load currentRf and Xf is the resistance and reactance of the feeder. (Rf = R *L/1000; L= length of the feeder). ...
Where do we locate lightining arrestor in transmission line?
Latest Answer: LA is located at substation. it is not in the TL... ...
Why the capacitors are connected in delta? What advantage it having than star connection?
Why almost all large size synchronous machines are constructed with rotating field system type?
Latest Answer: In large type of machines the currents are high so tapping those currents from the rotating armature is difficulty in the point of view of brushes and sparks over there. So we keep armature in rest and to have the mechanical movement btn the field and ...
What happens when a transformer is supplied with direct current?
Latest Answer: If DC supply is given to transformer there will be no change in the flux with time so there is no emf induced in the primary and secondary windings and hence transformer action will not take place. ...
It is possible to run one DC machine as a generator or motor purposely? What adjustment we have to do for that operation?
Why tapings of Transformer is always provided on HT side? why not on LT side?
Latest Answer: In a transformer the HT winding carrying the less amount of current and the LT winding carrying high current.Due to the less amount of current, the transformer taping is provided in the HT side with less current rating. This also reduces the arcing effect. ...
How to calculate voltage drop in cables?
Latest Answer: Each Cable is specified with their R & X values per Km or Mtrs. For calculating Voltage Drop across cable the effective impedance Z must be calculated for given length of cable as Z = Square Root of {(R*R)+(X*X)}. Then the final Voltage Drop can be ...
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