what is inrush current in transformer?
Answer Posted / s das
When a transformer first energised, the transient input
current can be 10-50 times larger than the normal operating
current for first several cycles. This is called inrush
current. If the trans. is energised at voltage zero
crossing the maximum flux is requirred to support the
voltage is double the normal flux. This is because the rate
of change of the flux(decides the voltage drop against the
inductance) should be same as steady state condition to
support same input voltage, but the flux is started from
zero in case of transient and started from negative maximum
value of flux in case of steady state for zero crossing
voltage of positive cycle. Tran. normally operats at the
knee point of hysteresis loop, the tran. will enter into
saturation zone and a huge current will be requirred to
generate double flux. In saturation zone, the inductance of
the core will be decreased and a considerable amount of
voltage(compared to drop against the coil) will be dropped
against the coil resistance9due to high current). The
voltage drop against the inductance of the coil is less
compare to normal condition and flux is not requirred to be
double. This could be severe if there is positive residual
flux at the time of energise at zero crossing of voltage's
positive half cycle. So the inrush current depends on the
time of energise, resistance of the coil and the residual
flux.
| Is This Answer Correct ? | 2 Yes | 0 No |
Post New Answer View All Answers
Air circuit breaker safety
give single line diagram of D.G distribution form alternator to main L.T panel?
how to flameproof electrical motor on the shaft?
Is electro plating what type of load whether resistive, inductive or capacitive loads
in cvt,there are two windings,1a,1n and 2a,2n.in my one project i use only one winding i.e.1a,1n. the other winding is not in use, so i connect it in open delta and want to close it by ibsertibg thermal resistor. the output of cvt is 132kv/115/sqrt3. plesae tell me exact value of resistor, so i may close it to avoid the resonance phenomenin. send me answer on this email adress please. aetcon-po@aetcon.com
what is EIB lighting control system? what is the advantages of this system?
sir plz send some previous year questions of jspl.
what is the prinsiple of dc motor and construction and working ,application of dc motor.
hi friends if you have any 400KV Substation Erection and installations Drgs please send to me.My email id:kandi.suresh441@gmail.com
What is cross over distortion? How it can be eliminated?
Which contains in POLE ASSEMBLY of a 11KV Kirloskar-make SF6 (Model No-FP620A12)? Will u clarify with drawing?
If any HVDC line is going with positive & negative(the negative usually have return path of current with earthing electrode). Now the question is if this HVDC earthed electrode which is using as return path and earthed any nearby 400kv or 220kv AC substation equipments. which will be the impact of this on AC substation & its equipment, how severe may be this and what should be the minimum distance require between HVDC earthed electrode and AC substation equipments? It's really an high engineering level question...Dare to answer and increase your knowledge.
what is the meaning of the symbol << >> put in transformer drawing
tell me some type of questions throught which i can prepare for exam and do my best
define the non synchoronism of synchoronous machine in general g or m??