Every mains/load in three phase can be connected in two configurations Star or Delta.

Now lets understand what is the difference between the two.In Delta configuration,there is no Neutral,we apply voltage phase to phase.The amount of heat generated by the current is much more than in Star configuration.

In Star configuration, the voltage applied to the load is always Phase to Neutral in all the three phases.The current generated is less than Delta configuration.

The effect of changing the configuration(Star/Delta) with similiar Resistive,Inductive and Capcitive Load is identified in the attached video.