1. what is the power factor and whatis his losses
2. what is the working procedure of 51RNB AND 87 relay

Answer Posted / 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.

Is This Answer Correct ?    4 Yes 1 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

Which power will flow first if we switch on a motor Active or Reactive? How?

4356


before synchronizing an alternator,power factor is leading ,why?

1015


how to find three phase complex power in per unit and MVA?

1649


Define resonant frequency?

719


i m doing DEEE in part time,can i join regular cources in BE,,IF i join what the cources can i select like (civil,ece,IT) ,,kindly advice

1633






th how could we differentiate between armoured copper and armoured aluminium cable what is the basic application? why we prefer the armoured copper as compared to armoured aluminium.

1463


Which device is used for the source of emission of electrons in a crt?

731


what is model question rrb junior engineer electrical gr.II

1543


where is core-type and shell-type construction suitable for transformers ?

1647


Name two types of electrical analogous for mechanical system.

729


What it the purpose of parallel phasing transfomers??

1508


how many joints are allowed in underground HT cable of 1 KM

1362


I am a possesor of c licence from 1993. I forgot to renew during the year 1998. During that time I was working at TNEB to till date. Is there any possibility to get renewed? or to apply for a new one?

1602


What do you mean by phasors?

628


What is EHT tariff or Power factor Tariff ????

1905