Why dc supply is used for closing and tripping coil of ht breakers. What happen if we use only ups ac supply only.

12 Answers   ACC, JLL, ZETDC,

---

in india ac frequency is 50hz, but in foreign countries it is 60hz,whwt is the reason

9 Answers   SVIT,

---

what is meant by reactive power ?

5 Answers  

---

DOES A MAGNETIC CIRCUIT CONSUMES ENERGY? IF YES, WHY?

6 Answers  

---

why we use REF and Differential Protection in one transformers?my doubt is both protections are operated in internal fault only.why we want to use 2 protections?please clarify.

7 Answers  

---

how did i get the competency certificate as electricle supervisor. iam completed my b.tech.but i dnt have any experince, this certificate is required for applyng ongc mangement trainees. what should i do sir please suggested me

0 Answers   ONGC,

---

What is the difference between isolators and electrical circuit breakers? What is bus-bar?

0 Answers  

---

What is the formula to calculate the rating of a three phase trnasformer

1 Answers  

---

Is it required to lay 2 runs of GI wires along with armoured cables from one power DB Machines of higher rating?

0 Answers  

---

why we use core type and shell type transformers?

2 Answers  

---

3 phase induction motor rotor field rotate at synchronous speed w.r.t ?

3 Answers  

---

if a motor is running at 1500rpm then how you can find its HP

1 Answers   Construction,

---