Answer / lalit barsker

vacuum circuit breaker is a device which is used to isolate
the faulty part of the power system from healthy part of the
power system & is used in switchgear.WHEN WE WANT TO SERVICE
OR MAINTEINANCE OF ANY SUBSTATION OR WANT TO CLEAR THE FAULT
DURING THAT CONDITION WE CAN ISOLATE THAT PART OF POWER
SYSTEM SO THAT WE CAN WORK IN THAT CONDITION ISOLATOR IS
OPEN AND SUPPLY CAN BE INTERRUPTED.

Answer / purushotham naidu.

Vaccum circuit breaker,as the name indicates is used to
break the circuit in faulty conditions and Arc quenching
medium is Vaccum. Isolator, as the name indicates isolates
the part of the system on occurence of fault without
actually being quenching/interrupting the arc....

Answer / mahesh m

The vaccum c.b are used to dissconnect the ckt when fault
accurse in the ckt,aswell as the vcb is used to break the
ckt in abnormall condition,in tn the name indicates the
isolators are used to isolates the ckt and the supply can
be intterupted by the mains.

Answer / ramakishore karri

the purpose of the vacuum circuit breaker is to isolate the fault system after the occurance of the fault. So that circuit breaker contacts open, in case of isolator it isolate the power for maintenance of the sub station as u like depends on us and it should not require any relay for finding the type of fault and interrupt the supply. In case of circuit breaker relay is required for finding the type of fault and it interrupt the circuit breaker.

What is converter transformer? Diff b/w converter transformer and distribution transformer? why we use converter transformer in place of giving supply to drives?

1 Answers  

---

how hydrogen or helium is a cooling agent for alternator./ generator of big size.

1 Answers  

---

whose motors self starting synchronous or Induction motor?give fact reason why not self starting another mother

2 Answers  

---

why can we use cosine wave instead of sine in ac supply as both have same rms vale and ripple factor

0 Answers   Indcoil Transformers, Power Grid,

---

what is rating providing of contactor,relay,fuse unit for motor output power

2 Answers  

---

---

2 Diesel Generators 900KVA connected to the bus bar for essential load as an alternative for power taken from 11/440V 3KVA Transformer supplying this bus bar. my question here is in the event of power failure on 11KV side can I feed the power to 11 KV bus by using the same transformer as reverse feed, what will be the inrush current???

3 Answers   Ashok Leyland,

---

what is relay

15 Answers   HPCL, IOCL,

---

armature winding of dc machine produce alternating emf then it convert in to dc by using commutator.But only we consider armature resistance why don't we consider inductive reactane effect?

0 Answers   APTransco,

---

Why reactive power is needed in a power system? How is it being absorbed or delivered by alternators? For reactive power control we are changing excitation but reactive power absorbing or delivering related to stator. How these two are interlinked? i want a detailed explanation with necessary expressions and figures?

0 Answers   Power Plant,

---

in a induction motor if we put capacitor across it will the power factor of the motor will improve? if yes how

6 Answers   Reliance,

---

the need of star to delta anddelta to star

2 Answers  

---

while buying 30 kva on line ups for 1 phase ouput, we ave to calculate the number of batteries for 2 hours back up? how to calculate the ah rating and number of batteries

1 Answers  

---