Which type of starter can be used for three-phase induction motor?
Direct-on-line starters are the simplest type of starter. A DOL starter connects an induction motor directly to the power source via a three-phase contactor. A DOL starter usually includes overcurrent protection and overload protection.
Which starter is used in induction motor?
The star delta starter is used for starting of induction motor above 5 H.P. Auto Transformer – The necessity of reduction of starting current to avoid failure of motor can be effectively done by auto transformer which consists of a single winding.
What is the formula for slip?
Slip speed is the speed difference between the Synchronous speed and Rotor speed. Slip speed = Synchronous speed – Rotor speed = Ns -N. Slip, s = (Ns – N) / Ns.
Why a starter is required to start a 3 phase induction motor?
The three phase induction motors are self-starting due to rotating magnetic field. But the motors show tendency to draw very high current at the time of starting. … Hence there should be a device which can limit such high starting current. Such a device which limits high starting current is called a starter.