Answer / nishant

For staring of Motor above 5 HP we need a starter with
overload protection e.g. Star-Delta Starter and D.O.L.
Starter for limiting starting current as motor takes 5-7
times of its full load current during starting So if we
start 20 HP motor Directly the line fuses will Blown Off
due to high starting current.

Answer / sdr

Dear readers, you may please note that Induction motor of
any size can be started directly-on-line provided that the
system in which it is connected should be healthy enough to
keep the system voltage steady at the time of starting.It
is not at all deirable to use a starter if your system is
healthy.In practice ,we usally don't know how much our
system is loaded,so be at a safer side, we use starters to
start Inductin motors.Thus starters limit the high inrush
current at starting & keep the system voltage almost steady
to let peform the other machines steadily.
If a 20 HP motor started in star & kept continuosly running
in star, it will run but the capacity of motor will reduced
to 57.73percet of the rated one.

Answer / mallikarjuna

Dear all readers so that if we 20hp motor start directly in
star nothing will happen and starting current will
less,suppose if connect to the motor in DOL starter the
starting current is 5-6 times full load the starting
current is around 150 amps ,when we connect to the star the
starting current is 60amps

Answer / ramya

above 10 hp we required starter bcoz, during the starting
of the motor ll get damage due to over starting current,
over voltage, increase in winding temparature,
thus to controll those faults we need decrease in starting
current, thus we run the motor with the starter. the name
itself indicates that it is uesd to start the drive or
motor.

Answer / hari

DIRECT STARTING WITHOUT STARTER IS POSSIBLE FOR DOL type
windings only,not for double cable motors.sudden load will
effects the transfomer and other electricl accessories.

Answer / dharmesh doshi

motor have no any problem to run but power consumption is high due to low power factor.

Answer / umesh

whenever we starts the 20hp motor directly with the mains
then its winding will be burnt, because the motor winding
have less then 10ohms, whenever current flows though the
winding the current will be 5000A, then it will be burnt.
that's way we use the starters for safty.

Answer / brijesh soni

If the motor strrted ok but if any Problem during at the
running as single phasing, over lodin, the motor will be
never Trippd but it will be Burn out

Answer / amit kumar

In this case , it delivers only one third power of the
rated capacity of the motor.

Answer / er.nitesh

Nishant is right but i want to say above 5 HP we use Star
delta starters and below it we use D.O.L.

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