Answer / arun_sekar_1986

1.Power Factor is defined as the cosine angle between
voltage and current.
From Power triangle cosine angle is defined as the adjacent
by opposite side.
ie., cos angle=kW/kVA


2. 51-AC Time Overcurrent Relay is a relay with either a
definite or inverse time characteristic that functions
when the current in an ac circuit exceed a predetermined
value.

87-Differential Protective Relay is a protective relay that
functions on a percentage or phase angle or other
quantitative difference of two currents or of some other
electrical quantities.

Answer / gunasekaran

low P.F following effect will accure.
1.KVA=KW/PF for low PF KVA ratng so equipment size will
incress.
2.PF is low more current so transmission loss will more.and
conductor size also incress.
3. poor voltage regulation
4.M.d incress.
51-idmt o.c and earth fault
87-diffrential relay it is operating B/W primary and sec
current diffrence.

Answer / vinod shnde

Mr. arun,cosangle=adj side/hypo

three owners X, Y, z owned some tractors with them, on the first month x gave away the same amount of tractors to y and z ( as much as they possed), similarly in the 2nd month y gave of to x and z similarly by third month z gave to x and y. after this all X, Y, Z had 24 tractors each.

2 Answers   econ,

---

WHY TRANSFORMER RATING IS MENTIONED IN KVA RATHER THAN KW

5 Answers  

---

if you asked to choose a ckt breaker from MCB & MCCB for 32A which one will be best and why??

7 Answers  

---

Why electrical engineer use Cu Strip for transformer neutral why not GI Strip? What if we use GI instead of Cu does it affects the transformer performance.

7 Answers  

---

what is the design voltage for 6.6KV 2000 KVAR HT capacitor?

1 Answers  

---

What makes the difference between 50Hz supply and 60Hz supply which one is economical? What is the use of using increased frequency?

5 Answers   ABB,

---

how to get 48 V DC I have ... 1. 12 volt power supply board 2. DC power supply ( max. 30 v) 3. 9 volt batteries ( 2 - not chargeble)

2 Answers  

---

what is frequency? and its importance

3 Answers  

---

Tesla is the unit of which parameter?

4 Answers   Ecil,

---

what is cascade speed control device?and how this device control the speed of motors?

0 Answers   ABB,

---

why total tape position are odd in number in Power transformer ?

1 Answers  

---

what do you mean by 1 ton in AC`s

36 Answers   Bhel, Bosch, ITC Infotech,

---