Question

J. List two methods for overcoming starting problems in an Induction Motor. Briefly describe them

Answer 1

Sterotring methods methods & 1) Direct On Line (DOL) starting 2 stator Resista. Reactor starling.. 3) Auto transformer starting 4 star - Delta stasting" s) Rotor Resistance starting: Reduced Voltage starting , Direct on line (DOL) starting - started with rated voltage applied across stator, so it don't control stasting i Lis used for fractional kilowatt rating : DOL starting is preferred (starter) for the motors which gets quickly accelerated ( mofor gets accelerated quickly then stiti SE ik ooizv.) Under / No voltage protection, overload protection with the help of Bimetallic strip is used in DOL staster: Advantage : Economic. : 2 withi LE W > stator Resistor) Reactor starting - x. Iste Additional external Resistance or Reactors are connected in seme AM1 asith statöriwindings... Due to these voltage across the stater winding get reduced f.com mresponding to the tasting current get_reduced ( because Resistor of Reactor couces additional Vitg.drops) Resistors are preferred over Reactors; becaure Reactors to pof. so motor will operate af Low Lagging_P.F. let XV be the voltage (reduced voltage) gerocs stator, x< 'x Ist will be the arrent at starting Tst x² SF TE If Used uplo po kw motors. * It is +

1) Auto transformers starting V. I, = va I V IL = nxn Isi Texts Isc (Tapping 7:) IL V. 12V © Dobro An autoxmer is used for reduced vite.starting, which is efficient beat eyensin :- Preferred for High Rating motors-generally. These is tapping % (x) by which valtage across the stater and staəting 2. current is correspondingly reduced. The efteet of starting torque is prepare Ist i 1/Isc)? Se JF Auto X mer power drauen - motor power 231 - Tapping % (P. drawn V, LT - VA-Iss a = x²Isa Line: current drawn by Alfoxmer. 0