Answer / nishant2110

This is the standerds fixed once so that we can use all
apllainces without bouthering to change its
frequency.Otherwise we would have needed extra appaince
called frequency changer for all different application like
we use transformer as voltage changer.

Now question arise why 50 hz or 60 hz as standerds??
Because, Higher frequency generation needs high synchronous
speed which may results in mechanical instabilty of rotor.
and also may lead more friction loss.
Lower frequency may results in voltage fluctualtion which
will result in fluctuation in lights of bulbs. also it will
be very difficult to rectify in constant dc.

so we cant use very high frequency niether very low.. so
somewhat intermidiate value has been selected as 50 or 60
hz as standards.

we can use frequency between 40 hz to 75hz without having
any much damage. But once standards has decided so decided

Answer / bhagya

actually the system will be reliable wen we frequency
between 40to 75hz,but in india we are using 50hz because
copper and core losses depends upon frequeny..nd the other
thing iswe are basically established with tat frequncy in
the time of british ruling.all the machines & euipments are
designed to tat frequncy...nw we cant change..all tat

Answer / bala

because the internal current goes up and this might cause faster deteriation of the insulation on the wiring, which causes shortcircuit and this may lead to fire, which can burn down your house!

What happens:
In transformers (like input transformer of the equipment) the current goes up.

In motors (like cooling ventilator or compressor) also the current goes up, the turns of the motor depends on the frequency, which means the turns are 17% higher if you go from 50 Hertz to 60 Hertz and 17% lower if you go from 60 Hertz to 50 Hertz, plus in this case the internal cooling is lower!

Answer / raj kumar

we can use amy frequency,,,but to stablity of power
system,all equpments are runed under same frequence,in our
country we fixed 50 hzs,,,,

What is the difference between type1 and type2 relay protection co-ordination for motor feeders

0 Answers   DAE,

---

What is water cooled chiller plant?

1 Answers   Gulf, IOCL,

---

what is interpose? where it is used and why it is used?

0 Answers  

---

why we use post insulators in no ofstacks at substation for supporting equipment ? why we not use single post insulator

3 Answers  

---

1. A 380 / 220 V r.m.s. 3-phase 4-wire circuit carries loads of 8 + j8.1 ohm; 4 + j4.1 ohm; and 2 +j2.1 ohmin the three phases respectively. The length of the circuit is 100 m, and the resistivity of the phase conductors is 0.0005 Ω/m. The neutral conductor is of the same size as the phase conductors. a) Select a reference angle 0for the first phase. Then write down the three phase voltages in both polar format and complex number format. b) Make appropriate assumptions, and take temperature effects on resistance is insignificant. Calculate the currents in the three phases. (Note: Determine conductor resistance, and apply Kirchhoff’s Voltage Law) Based on the result, suggest a main switch rating for the circuit. c) Show your preferred direction of neutral current in a diagram, and then determine its value. (Note: Apply superposition principle, and Kirchhoff’s Current Law) Use its magnitude to show that in this circuit, the unbalanced load may increase the voltage drop in some of the phases. (Note: Also observe the common volt drip in neutral) State your assumptions, if there are any. d) Suddenly the neutral wire of the circuit is broken. Estimate the new currents in the first phase, i.e. Phase L1. State your assumptions, if there are any.

0 Answers  

---

I have running 4 generator in paralel.All generators Voltages is same(470 V),KW also same (100 KW) but only No2 generator Amper is high than another generators. DG No:1,3,4 470V,100KW, 150 A DG No:2 470V,100KW,400 A

4 Answers  

---

why high speed tripping relay is used in protection circuit why not normal relay

0 Answers  

---

can we conduct the swineburne's test on a dc series motor? why?

0 Answers  

---

Why lose 1 phase voltage in 33kv to 415v stepdown transformer

0 Answers  

---

what is the purpose of commutator in DC motor?

3 Answers  

---

what is p.s impedance measurement test in earthing transformer?

0 Answers   Greenko,

---

What will be the diameter of pipe between conservation tank and transformer

0 Answers   JLL,

---