Answer / natarajanramkumar

D.O.L Starter=Direct On Line Starter
1.It does not decrease the starting current.
2.It is cheap.
3.It connects directly the motor with supply for starting
as well as for running.
Star-Delta Starter
1.It decrease the starting current to 1/3 times.
2.It is costly.
3.It connects motor first in star at the time of starting
then in delta for running.

Answer / shankar rao

DOL is Direct on line starter, it is used upto 50 H.P Motors
Star delta starter is Starting time Motor Phases are in Star
and Running time it is convert to Delta scheme.( Because
High H.P Motors are Starting time we are appling Low voltage
by using Star system, and it is increase the Torque.)

Answer / ramanjaneyulu

DOL MEANS DIRECT ON LINE STARETER WE CAN USE DOL UP TO 5KW
RATEING IT CONNECTED DIRECT TO THE SUPPLY THROUGH OVER
LOAD RELAY IT DOES NOT REDUSE THE STARTING CURRENT. star
delta are used havy rateing motors because it limits the
starting current in 1/3 tmes of starting current

Answer / shafiq

in star/delta we can limit the current .but during starting
of motor in DOL motor will draw 3-5 time of its FLA

Answer / sunil guru

DOL-- As its meaning suggests "DIRECT ON LINE" the motors are provided the direct supply without any changes & this starters are only used for protection purpose (not for soft starting of the motor)and are preffered only upto 10 Hp motors in industries....

STAR DELTA--- are preffered beyond DOL range
first reduced voltage(1/3 of supply V) is given to the motor & as it reaches 70-80% of its rated speed full V is given. (it is the function of changing 4m star to delta)is done to reduce the starting current and to protect the motor.......

for any disagreement mail me at parmar20072008@yahoo.com

Answer / panil ahir

DOL is just running protection of motor while star-delta is running and starting protection of motor. It reduces the starting current of motor by increasing the resistance value of coils. As the starting resistance value is doubled the actual coil resistance, starting current reduces 1/3 times to protect the motor coils. 

Answer / rohan k trivedi

DOL MEANS DIRECT ON LINE STARETER WE CAN USE DOL UP TO 110
KW MOTORS SPECIALLY WHERE THE STARTING TOURQUE IS LOW AND
STARTING KICK IS ALSO SMALL. WHILE STAR DELTA IS DESIGN TO
REDUSE THE HIGH STARTING KICK. GENERALLY FANS BLOWER AND
COMPERSSOR MOTORS HAVE HIGH STARTING CURRENT DURING THE
STARTING SO IT IS GOOD TO USE STAR DELTA INSTEAD OF DOL.
ANOTHER DIFFERENCE IS THAT DOL HAS ONLY ONE CONTACTOR WHILE
STARDELTA HAS THREE CONTACTOR.

Answer / mallikarjun

the dol is direct online ie if press the start button it
start direct by closing the single contactor.and star-delta
starter is by redusing the volatge this will helps to
incrase the traque.

Answer / j.karthik

DOL Starter :
This starter is costwise cheap. it doesnot reduce the
starting current of the motor. The starting current of the
DOL starter is 6 to 7 times of the full load current. We can
use this starter for any higher kW range motors also even
6400kW motor.(In my working place using this DOL starter for
this 6400kW motor.

Note: for any standard cannot mentioned this much of the kW
motors only use in this type of starter nu..

Star/Delta Starter :
This starter is costwise higher. It can reduce the
starting current of the motor. The starter current of the
star/delta starter is 3 to 5 times of the full load current.
Generally in my working place this starter can be use above
75kW motors.

Answer / bathabile

DOL is a soft starter

how to calculate voltage drop and followed by cable calculation?is there avail in formula?

0 Answers  

Why Lighting transformers are used? what will be the current if lightings connected through direct raw power?

1 Answers   BMM,

Is phenomenon of resonance is harmfull fr the machine? if not or if yes please explain it?

0 Answers   Bhel,

I want to ask that is there any relation between current denesity of copper and material purity. also is ther any standard which defines the standard current denesity of material.

0 Answers  

Why we oil in tranformer/

5 Answers  

Why different types of connection in transformers are used? (star/star,star/delta,delta/star,delta/delta)Why we are only taking in consideration of star/delta type transformers? if only star/delta is good in practice where doses other type of transformers are used? Note: i want to know place of using different types of transformers other than Star/delta type with brief description.

1 Answers   Electrical Tech,

what do you mean by the "bay" in a switchyard? how to determine exact number of bays in a substation?

8 Answers   Essar, L&T,

what is the reason of capacitor failure in alternator which is working with 10 kva dgset

0 Answers  

what is two wattmeter test

2 Answers   Jindal,

Why air circuit breaker off due to power failure?

0 Answers  

How many types of faults are there in 3 phase power system?

0 Answers  

WHY WE DO NOT TAKE THE POWER FACTOR MORE NEARER TO UNITY IN AC GENERATOR?

1 Answers