Star Delta starting is the best known and perhaps the most widely used low voltage
starting method. It is used to start the pump’s motor with lower levels of mechanical
stress and with current limitation during start-up; it does this with the aid of a timed
system which switches the control contractors installed inside the panel.
Star-delta starting reduces starting current and torque to values of 33% (1/3) of
those measured during direct starting. During start-up, the currents flowing through
components are lower than the motor’s related current.