The document discusses the necessity and functions of starters for both DC and AC motors, emphasizing their critical role in protecting motors from high inrush currents and ensuring controlled operation. It outlines various types of starters such as three-point, four-point, DOL, and star-delta starters, along with their wiring diagrams and automatic/manual variations. The presentation concludes with a brief overview of different starter types and their applications.

1. PRESENTATION ON
DC and AC motor starter

2. Content
• Necessity of starter
• Function of starter
• Dc motor starter
• Ac motor starter

3. Necessity of starter
• At starting ,the speed of motor is zero so that
the back e.m.f. In the armature is zero.
• Armature resistance is so low, if it is
connected to power supply directly ; huge
current will pass thru armature.
• The huge current may damage the machine,
major heat, very high speed in case of DC
series motor.
• Ia = V/Ra

4. Function of starter
• Start and stop the motor.
• Limit inrush current where necessary.
• Permit automatic control when required
• Protect motor and other connected
equipments from over voltage, no voltage,
under voltage, single phasing etc.

5. Type of starter
for DC Motor
• Three point starter for shunt motor
• Four point starter for compound motor
For AC Motor
• DOL Starter
• Star-Delta
• Auto-transformer

6. Dc motor starter
• Three point starter
• Four point starter

7. Three point starter

8. Four point starter

9. Ac motor starter
• Dol starter
• Star-delta starter
• Automatic rotor resistance starter
• Auto transformer starter

10. Wiring Diagram of DOL Starter:

11. Star delta starter
• Two types
1. Manual star delta starter
2. Automatic star delta starter

12. Manual star delta starter

13. Manual star-delta starter
• Commonly used

14. Automatic star delta starter

15. Automatic rotor resistance starter

16. Auto transformer starter
There are two types
1. Automatic auto transformer starter
2. Manual auto transformer starter

17. Automatic auto transformer starter

18. Manual auto transformer starter

19. •Thank you