Answer / fahad

usually the armature resistance of a motor is very low.So
when we apply the line voltage across the motor,a very large
current flows into the armature circuit &it will burn
out(starting current may be 30 times the full load
current).so we are using starter(starting resistance in
series with armature)&slowly cutting it as motor speeds
up..Once it attains full speed,a back emf is produced & now
it will limit the armature current

Answer / u.chandarasekar

Avoid Starting Trouble

Answer / prashant v . panchal

the starters are used to start the motors & to save the
motor winding from heavy starting current.

Answer / raviteja

THE RESISTANCE OF THE ARMATURE OF THE MOTOR IS MADE VERY
LOW IN GENERAL TO REDUCE THE LOSSES==>>IMPLIES THAT AS THE
RESISTANCE OF THE MOTOR IS VERY LOW,,IT IS ABLE TO GRASP
THE HEAVY CURRENTS FROM THE SUPPLY NEARLY 4-5 TIMES THE
RATED CURRENT OF THE MOTOR,,SO THERE IS A CHANCE OF DAMAGE
TO ARMATURE WINDING BCOZ OF THESE HEAVY CURRENTS,,SO,TO
OVERCOME THESE PROBLEMS,,A STARTER IS USED FOR THE SMOOTH
OPERATION OF A MOTOR WITH OUT GETTING ANY DAMAGE

Answer / salim

The starting current of motor is very high, as per its
rated full load current. It also has the low resistance. if
we start the motor without starter,since the resistance is
low, heavy current will flow through the windings of the
motor and will burn the windings. that is y we use starter
to increase the resisitance or u can say to reduce the
voltage .

Answer / christopher king

Most of you have given a answer that starter is used to reduce starting current.Agreed..but one kind of starter doesnot agree with the answer above.
In DOL starter( direct on line starter) the starting current is 5 times more than the normal current. here starting current is not reduced and could anyone explain why do we have DOL starter for an ac motor?

Answer / priyadharshini

At the starting point Back emf Eb=0 so that large amount of current is produced so it will damage the armature windings so that starter is used to avoid the problem

Answer / boobesh

1.To limit the starting current

2.To provide against low voltage and over load condition

Answer / senthil

When a motor is started it requires more torque, more torque
means more current that is apporx 5-8 times of the normal
load current.Since, the resistance value of the motor is
small it will get damaged due to the excessive current flow.

So, the ultimate aim is to reduce the starting current
( I=V/R) so it can be achieved either by reducing the
voltage applied to the motor or to increase R by adding
external resistance in series to the motor windings.

This is what done in all type of starters either it is a
auto transformer starter or a star delta starter

Answer / saurabh shekhar

When a dc motor is initially energized,there is no back emf
because the rotor is not rotating.initially the motor draws
higher current than the normal full load current and so this
high current can damage the commutator,the winding or the
power supply equipment.Therefore,a starter is needed with
current limiting resistor or a series of resistor until the
motor gets up to the rated speed.

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