This ppt is for your education purpose. I can explain the electrical starters in very best ways , you can understande the all electrical starters in very easy methods. For your any inquiry, CONTECT NO : - 9082557285 CREATED BY : - AYUSH .A. PITHAL

1. PREPARED BY :- AYUSH PITHAL
TEAM NAME
ELECTRO SPARKLE

2. TYPES OF STARTERS
1. DOL STATER
2. STAR-DELTA STARTER
3. ROTER RESISTANCE STARTER
4. AUTO TRANSFORMER STARTER

3. CONTENT
1. WORKING PRINCIPLE OF STARTERS.
2. CIRCUIT DIAGRAMS.
3. ADVANTAGE & DISADVANTAGE OF STARTERS.
4.CONSTRUCTION OF STATERS.
5. FUNCATION OF STARTERS.
6.APPLICATIONS OF STARTERS.

4. 1) WORKING PRINCIPLE OF STARTERS

5. DOL STARTER WORKING PRINCIPLE
• The working principle of a DOL starter begins with the
connection to the 3-phase main with the motor. The control
circuit is connected to any two phases and energized from
them only. When we press the start button, the current
flows through contactor coil (magnetizing coil) and control
circuit also.

6. STAT-DELTA STARTER WORKING PRINCIPLE
• This is the reduced voltage starting method. Voltage
reduction during star-delta starting is achieved by physically
reconfiguring the motor windings as illustrated in the figure
below. During starting the motor windings are connected in
star configuration and this reduces the voltage across each
winding 3. This also reduces the torque by a factor of three.

7. • STAR/DELTA STARTERS ARE PROBABLY THE MOST
COMMON REDUCED VOLTAGE STARTERS. THEY ARE
USED IN AN ATTEMPT TO REDUCE THE START CURRENT
APPLIED TO THE MOTOR DURING START AS A MEANS OF
REDUCING THE DISTURBANCES AND INTERFERENCE ON
THE ELECTRICAL SUPPLY.
• Traditionally in many supply regions, there has been a
requirement to fit a reduced voltage starter on all motors
greater than 5HP (4KW). The Star/Delta (or Wye/Delta)
starter is one of the lowest cost electromechanical reduced
voltage starters that can be applied.

8. ROTER RESISTANCE STARTER WORKING
PRINCIPLE
• Operating principle The EPM rotor starter is normally used
to control the starting of a slipring motor, and the starting
current is generally limited to a maximum of 250% FLC.
Optimal starting torque for each application is normally
selected by the choice of the initial value of resistance.

9. AUTO TRANSFORMER STARTER WORKING
PRINCIPLE
• An autotransformer is an electrical transformer with only
one winding. The "auto" (Greek for "self") prefix refers to
the single coil acting alone, not to any kind of automatic
mechanism. In an autotransformer, portions of the same
winding act as both the primary winding and secondary
winding sides of the transformer. In contrast, an ordinary
transformer has separate primary and secondary windings
which are not connected to each other.

10. 2) CIRCUIT DIAGRAMS

11. DOL STARTER CIRCUIT DIAGRAM (THREE PHASE)

12. DOL STARTER ORIGINAL PRECTICAL VIEW

13. DOL STARTER CIRCUIT DIAGRAM (SINGLE PHASE)

14. STAR-DELTA STARTER POWER CIRCUIT
DIAGRAM

15. STAR-DELTA STARTER CONTROL CIRCUIT
DIAGRAM

16. ROTOR RESISTANCE STARTER CIRCUIT
DIAGRAM

17. AUTO TRANSFORMER STARTER CIRCUIT
DIAGRAM

18. 3) ADVANTAGES & DISADVANTAGES

19. ADVANTAGES OF DOL STARTER
•Very cheap and economical Starter.
•More comfortable, simple to operate and control.
•The control circuit is much simpler.
•Very Easy to troubleshoot and easily understandable.

20. DISADVANTAGES OF DOL STARTER
• The starting current of the motor doesn’t reduce.
• Direct ON Line starter has very high starting current or too
much current 6 to 8 times of full load current.
• Due to the huge thermal stress on the motor, the lifespan of
the machine reduces.
• DOL starter is only suitable for motors of rating less than
10kw.

21. ADVANTAGES OF STAR-DELTA STARTER
• The operation of the star-delta method is simple and rugged
• It is relatively cheap compared to other reduced voltage
methods.
• Good Torque/Current Performance.
• It draws 2 times starting current of the full load ampere of
the motor connected

22. DISADVANTAGES OF STAR-DELTA STARTER
•Low Starting Torque (Torque = (Square of Voltage)
is also reduce).
•Break In Supply – Possible Transients
•Six Terminal Motor Required (Delta Connected).
•It requires 2 set of cables from starter to motor.

23. ADVANTAGES OF ROTOR RESISTANCE
STARTER
•lower losses in rotor
•lower slip, the motor will slow down less with
increasing load

24. DISADVANTAGES OF ROTOR RESISTANCE
STARTER
•lower starting torque
•higher starting current

25. ADVANTAGES OF AUTO TRANSFORMER
STARTER
• For transformation ratio = 2, the size of the auto
transformer would be approximately 50%...
• An auto transformer has higher efficiency than two winding
transformer.
• Auto transformer has better voltage regulation as voltage
drop in resistance and reactance.

26. DISADVANTAGES OF AUTO TRANSFORMER
STARTER
• Because of electrical conductivity of the primary and
secondary windings...
• The leakage flux between the primary and secondary
windings is small and hence the impedance is low.
• The connections on primary and secondary sides have
necessarily needs to be same,...

27. 4) CONSTRUCTION OF STATERS

28. CONSTRUCTION OF DOL STATERS.
• DOL Starter basically comprises of only two buttons one of
them is ‘green’ and other is ‘red’.‘Green button is used for
starting and ‘Red’ button is used for stopping the motor. The
Direct ON Line Starter actually consists of a contactor, an
MCCB or circuit breaker, and an overload relay for
protection whenever a fault condition occurs. The above
mentioned two buttons ‘stop’ and ‘start’ or also called as
‘Red’ and ‘Green’ buttons are used to control the contacts.

29. CONSTRUCTION OF STAR-DELTA STATERS.
• Push Buttons
There are two push buttons are used in the star delta starter of induction motor
Start (NO)
Stop (NC)
• contactor
There are three contactors are used in star delta starter of induction motor
• Main contactor
Star contactor
Delta contactor
• Timer
• Overload relay

30. CONSTRUCTION OF ROTOR RESISTANCE STATERS.
• To limit the rotor current which consequently reduces the current
drawn by the motor from the supply, the resistance can be inserted in
the rotor circuit at start. This addition of the resistance in rotor in the
form of 3 phase star connected rheostat.
• The external resistance is inserted in each phase of the rotor winding
through slip ring and brush assembly. Initially maximum resistance is
in the circuit. As motor gather speed, the resistance is gradually cut-
off. The operation may be manual or automatic.

31. CONSTRUCTION OF AUTO TRANSFORMER STATERS.
• An autotransformer has a single winding with two end terminals and
one or more terminals at intermediate tap points. It is a transformer
in which the primary and secondary coils have part of their turns in
common. The primary voltage is applied across two of the terminals,
and the secondary voltage taken from two terminals, almost always
having one terminal in common with the primary voltage.[2] Since the
volts-per-turn is the same in both windings, each develops a voltage in
proportion to its number of turns.

32. 5) FUNCATION OF STARTERS

33. FUNCATION OF DOL STARTER
• DOL starter consists of MCCB, contactor, and overload
relay. It acts as a switch under normal working condition by
providing the means to switch ON and switch OFF the
motor. It holds the switch ON condition when motor is
running by the use of latch mechanism and interrupts the
flow of current to the motor once the stop button is pressed.

34. FUNCATION OF STAR-DELTA STARTER
• For star delta starter,the basic function is to enable the
motor to start and the motor windings are configured in a
star formation to the supply voltage. The voltage applied for
star delta starter to the individual motor winding is
therefore reduced by a factor of 1√3 = 0.58 this connection
amounts to approximately 30% of the delta values.

35. FUNCATION OF ROTOR RESISTANCE STARTER
•Starter means which limits starting current(major
priority) and also it can be used to control the speed
of a machine. Rotor resistance starter is used with a
wound rotor induction motor. It uses an external
resistance in the rotor circuit so that rotor will
develop a high value of torque.

36. FUNCATION OF AUTO TRANSFORMER STARTER
• An Auto Transformer is a transformer with only one winding wound
on a laminated core. An auto transformer is similar to a two winding
transformer but differ in the way the primary and secondary winding
are interrelated. A part of the winding is common to both primary and
secondary sides. On load condition, a part of the load current is
obtained directly from the supply and the remaining part is obtained
by transformer action. An Auto transformer works as a voltage
regulator.

37. 6) APPLICATIONS OF STARTERS

38. APPLICATION OF DOL STARTER
• DOL starting is sometimes used to start small water pumps,
compressors, fans and conveyor belts where high inrush
currents do not cause any harm
• If the high inrush current of the motor does not cause an
excessive voltage drop in the supply circuit a direct online
starter can be used.

39. APPLICATION OF STAR-DELTA STARTER
• The star-delta method is usually only applied to low to medium
voltage and light starting Torque motors.
• The received starting current is about 30 % of the starting current
during direct on line start and the starting torque is reduced to about
25 % of the torque available at a D.O.L start. This starting method
only works when the application is light loaded during the start. If the
motor is too heavily loaded, there will not be enough torque to
accelerate the motor up to speed before switching over to the delta
position.

40. APPLICATION OF ROTOR RESISTANCE STARTER
• Slip Ring Motors are primarily used to start high inertia load
or a load that requires a starting torque across a full speed
range.
• By correctly selecting the resistors inserted into the Rotor
circuit, the motor is able to produce maximum torque at a
relatively low current from zero to full speed.

41. APPLICATION OF AUTO TRANSFORMER STARTER
• They are generally used to connect transmission lines of slightly different voltages (
e.g., 115 kV and 138 kV or 138 kV and 161 kV)
• They are employed to compensate for voltage drops on long feeder circuits where it
is important that each load device receives the same voltage ( e.g., on airfield
lighting circuits to ensure uniform lamp intensity)
• They offer variable voltage control in the laboratory setup: as we move the sliding
contact, virtually all of the coil can become the series coil. Therefore, the entire coil
must be sized for maximum current.
• They are used to adjust the transformer output voltage in order to keep the system
voltage constant with varying load.

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