PRESENTATION ONDC and AC motor starter

Content

• Necessity of starter• Function of starter• Dc motor starter• Ac motor starter

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

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.

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

Dc motor starter

• Three point starter• Four point starter

Three point starter

Four point starter

Ac motor starter

• Dol starter• Star-delta starter• Automatic rotor resistance starter• Auto transformer starter

Wiring Diagram of DOL Starter:

Star delta starter

• Two types 1. Manual star delta starter2. Automatic star delta starter

Manual star delta starter

Manual star-delta starter

• Commonly used

Automatic star delta starter

Automatic rotor resistance starter

Auto transformer starter

There are two types 1. Automatic auto transformer starter2. Manual auto transformer starter

Automatic auto transformer starter

Manual auto transformer starter

•Thank you