T-Phi Network (Star-Delta) Using Relays and Timer

1. Introduction

In electric circuit star and delta circuit consist of 3 loads which in star circuit they are connected in form of a star while in delta circuit are connected in delta form as in Figure 1.

The application is usually used in (Alternate Current) AC motor where it has to start slowly. Starting the motor through a high current immediately could blow the motor as the starting current equals to the normal current multiplied by v3 (=v3 x I). It’ll be fine if the current is 5A (ampere) (I_start=v3 x 5…