Answer / anchal

coz at the start the slip is maximum,
Rotor conductors are stationary in the beginning and the relative speed between the rotor conductors and rotating magnetic field is maximum, and hence emf across rotor conductors is max in the beginning(e=blv) means current is max, as the rotor starts rotating the relative speed becomes less and hence does emf and current.

Answer / sunil guru

AT START THEIR EXIST MAGNETIC FIELD & THE ELECTRIC FIELD IS ABSENT AND COMBINATION OF BOTH PRODUCES THE TORQUE AND ROTATES THE ROTOR...
TO PRODUCE THE FLUX IN THE CLOSE CIRCUIT OF THE ROTOR MOTOR CONSUMES THE CURRENT AND WITH THE CUTTING OF FLUX EMF IS GENERATED THEN THE GENERATED EMF IS CALLED BACK EMF OR COUNTER EMF .... AFTER THE PRODUCTION OF BACK EMF IT NEUTRALISE'S WITH SUPPLY VOLTAGE AND THEN WITH THE STAGE OF NORMAL RUNNING OF MOTOR THE CURRENT CONSUMPTION REDUCES...

SO AT START WITH THE WORK OF SETTING OF FLUX AND TO OVERCOME THE LOSSES THE STARTING CURRENT IS ALWAYS HIGH...

FOR ANY DISAGREEMENT MAIL ME AT parmar20072008@yahoo.com

Answer / praveen kumar.bodu

when motor is off. it consists of some back emf in it.and
also it appears like a short circuited i.e it has a full
load connection. at the time of start motor again it is not
possible to run motor initially when fulload isconnected.so
motor sinks more current.

Answer / viren

When motor at rest, the motor appears to be a transformer, with it's secondary winding short circuited, i.e. the rotor winding or squirrel cage is a closed circuit. This results in a low impedance to the system voltage and the motor has a "locked rotor" current of typically 6 times full load current, but also up to 8 and sometimes 10 times current.

Answer / ali_asgher107

Because at the starting of induction motor, the emf is zero

in a dc motor we supply current only to the armature conductors,from where is the field winding gets excited then??

3 Answers   RRB, Siemens,

At full load wat is the motor p.f And at no load will is the motor p.f?

0 Answers   GEPL,

what are the components of a start and stop motor control?

2 Answers  

What is NGR . What is the purpose of 10 sec ,60 sec rating of NGR.

0 Answers   KOTC,

why power factor is only cosine angle not sine angle?

2 Answers  

how we can select a transformer based on a particular load. suppose we have 4 motors of rating 40 h.p , 50 h.p, 80 h.p & 100 h.p. then what rating of transformer we can select. urgent. pls reply

6 Answers  

give me list of material for wiring of 20hp motor?

2 Answers   Alchemist,

one electromagnet is called

0 Answers  

how to do the ductor test?

0 Answers  

1. how much normal earth resistance in earth pits(neutral and body earth) and transformer neutral and body earth & panel earth.

12 Answers   HP, Malladi Drugs and Pharmaceuticals, Pearl Engineering, PL,

i am iti student i have project to do. that IS 100MW 220\33KV SUBSTATION I WANT TO KNOW HOW TO START, LIKE CALCULATION, WHAT RATING OF CT,CVT, PT, ISOLATOR LIGHTING ARRESTER WAVE TRAP CIRCUIT BREAKER IN 22OKV SIDE, ALSO TO WARDS 33KV SIDE PLS HELP ME WITH THIS, THIS MY LIFE NOW, I KNOW AUTOCAD, I LIKE TO KNOW HOW TO CALCULATE ALL THE THINGS

3 Answers  

what is the ka rating of mccb. and how it is decided .

3 Answers   Napino,