Answer / aditya

over frequency occurs when the RPM of prime mover goes above the rated speed. This protection is basically for prime mover and gives a trip signal to the prime mover in case of overspeed so that the centrifugal forces dont damage the prime mover and alternator rotor. This is generally a result of faulty speed governor or sudden throw off or throw in of large magnitude. In addition overspeeding will also result in increase of supply frequency. certian electronic equipments are very sensitive to freq and get damaged hence over freq protection is given.

We have a distribution transformer of 750KVA/11kv/440v and an AVR (Servo Stabilizer) of 750KVA on the LT side of distribution transformer. Also we have an ACB of 1200A on the output of distribution transformer (that is on the input of AVR). We want to have an MCCB on the output of AVR. What should be the rating?

0 Answers   SSPL,

---

The rotor current is directly proportional to slip. How?

3 Answers  

---

what is the use of capacitor in online ups?

6 Answers   Emerson, ups,

---

10 Mtr Hight of Lighting Arrestar how much area coverd??

0 Answers   OmniActive,

---

if generator is running in iso mode parrallel with grid and suddenly grid breaker off what will happen?

6 Answers   century,

---

Can a 150 kva 3 phase,440v/230v delta-wye connection stepdown transformer can be used in reverse as a step up tranformer ?

3 Answers   Meralco,

---

while calculating the power absorbed by a resistor connected to the output of a half wave rectifier circuit should we use rms or average current? explain with reason.

1 Answers   Vedanta,

---

what is is the potential diffrence between two phase ?

3 Answers   Bhel,

---

What are protections for dty type transformers

0 Answers  

---

What is a variable speed motor?

3 Answers  

---

During the troubleshooting of an inoperative shunt generator, you found the voltage to be 2+ volts; what is known from this. Is it (1). odds are the armature is good (2). odds are there is no field current flowing in field windings (3). odds are the armature is bad (4). both 1 & 2 are correct (5). both 2 & 3 are correct

2 Answers   Air Force,

---

hi friends ,iam working as genset AVR service engineer in electrical field from past 2 yrs throughout india . i plan to shift in some other job without travelling in same field because i con't travel,i dont know what i do for that so please guide me what job is suited for me,how i can serch the job please anybody helpme iam totally confused

4 Answers  

---