What is negative phase sequence?

Answer Posted / adil yousuf

Ans ; The negative phase sequence
current will flow due to diffence of three phase volages of
the system.If no difference of R Y B voltage is present,
the negative sequence current will not flow.
In rotating machines an unbalance voltage or current in one
phase winding due to elctrical faults or uneven load
further exacerbates the problem. The magnetic coupling
between the winding becomes uneven.
when subject to unbalance conditions, negative phase
sequence currents produce a counter rotating megnatic field
withrespect to the main field.
The resultant field rotates at double frequency and causes
underirable eddy-currents to flow in various structure such
as the machine rotor body , excitaation winding, stator end
winding and stator iron etc.

Is This Answer Correct ?    54 Yes 8 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

Why we use Electrical energy rather than any other type of energy, mostly? Explain behavior of open secondary CT and short circuited secondary PT in energized condition?

1580


how can I calculate charging current of cable/overhead conductor? what is roll of voltage in it ?

3438


What is the capacitance values of 132,220,400 & 765 kV current transformer

1684


What is meant by vector group

2170


where solid grounding and where grounding through ngr done and why?

2349


Is any AC drive(VFD) had a feature of DC injection braking? if available please mention the detail. i.e drive can supply braking torque when the motor in idle state.

1917


explain me the relation between torque, frequency,speed,voltage and current in the 3 phase induction motor?

2024


1.Can we use 6.6/11KV 300sq mm xlpe 3core cable for LT use (415 Volt). 2. If we use it for LT then what is the current rating

1474


impliment (AB)`+C to transistor representation

1598


if a.c supply is given to the motor,, what happen?

1922


if an insulated power and control cables of a running gas diesel gensets laid direct in an open trench i.e, trench bed is not rcc of a power house in which rain water, spillage water alwas exists and all power control cables remains submerged even when gas gensets of 480 kw each runningin on load. These power &control cables runs from power house to switchgear room through these trenches in which water remains most of the time. pl explain its merit & de-merit

1631


I am using submission of two ct in one and half scheme for 67/67N protection. Both CTs star point is grounded separately near ct box.Will two point ground give wrong tripping to 67/67N during fault or no matter.

1891


which fault is severe and why?between lll fault and lllg fault which fault is severe and y?

2259


i have seen one 8.4 MW synchronous motor in a plant located in bellary it is fixed with brushless rotary rectifier ,anybody can explain its start up principle

1740


what is the reactance,capacitance & impedence electrical armoured & unarmored Cables.

1885