Direct Online Starter

The Direct-On-Line or the DOL Starter is a method or starting motors where the supply voltage is directly applied to the motor terminals.  This results in heavy inrush currents and high starting torque.  

The heavy inrush currents may result in voltage dips in the system.  The high starting torque may result in damage to the coupling or to the connected load.

Thus, the Direct On Line Starter is used only in small motors such as those connected to pumps and blowers.