Direct On Line start is probably the simplest and traditional type of start and it is to connect the motor directly to the power supply performing therefore a full-voltage start-up.
It is often abbreviated with the acronym DOL.
DOL (Direct On Line) start is the simplest and most cost-effective system for starting pumps and motors and it is traditionally the most widely used. The induced current is the rotor is high. This results on a peak current on the network which can be 5 to 8 times the nominal current.
They are suitable for startup of small submersible pumps, deep well pumps or booster sets with surface pumps.
DOL control panels need a direct connection to the power supply network, which implies:
In consideration of environmental relief and energy saving Franklin Electric developed a High Efficiency 6" Submersible Borehole System, consisting of a synchronous submersible NEMA motor associated variable frequency drive and output filter.