The delta connection of the motor is to connect the windings of each phase one end at a time, and lead each connected point as three phase lines of three-phase electricity. The motor phase voltage is equal to the line voltage when the delta is connected; the line current is equal to 3 times the phase current of the root number.
The star connection of the motor is to connect one end of each phase winding to one point, and the other end of the winding is used as a lead line, which is respectively three phase lines. When star connected, the line voltage is 3 times the root of the phase voltage, and the line current is equal to the phase current.
Due to its small output power, the star connection method is often used for low-power, high-torque motors, or motors with higher power. This is less for machine loss, and then replaced with a delta connection after normal operation. This is the star that is often said - the triangle starts.