Three-Phase Induction motor Star and Delta Connection Diagrams

This technical drawing illustrates the two primary wiring configurations for three-phase induction motors: star (wye) and delta connections. This top section depicts the star connection, where the terminal points U2, V2, and W2 are internally connected to form a neutral point, while U1, V1, and W1 are connected to the three-phase supply lines L1, L2, and L3 respectively. This configuration provides reduced starting current but lower running torque. The bottom section shows the delta connection, where terminals are interconnected (U1-W2, V1-U2, W1-V2) to form a closed loop, with L1, L2, and L3 connected to the junction points. The delta configuration delivers higher torque but draws approximately 1.73 times more starting current. Each connection type is illustrated through three complementary views: a symbolic winding diagram showing the impedances, a terminal box representation, and a practical motor connection schematic with color-coded power lines (red, yellow, blue for L1, L2, L3). The drawing serves as an essential reference for motor installation and maintenance technicians to ensure proper electrical connections based on load requirements and starting conditions.