Three Phase Motor Connection Diagram

Fig. 3-phase motor wiring diagram

3-phase motor wiring diagram

Three-Phase Motor Connection Schematic, Power, and Control Wiring Installation Diagrams. Star-Delta (Y-Δ) 3-phase Motor Starting Methods.

Three-Phase Motor Connection Diagram and Wiring Procedure · Find out the terminals of each winding of the motor.

We will show you the three-phase motor terminal connection or wiring procedure for- 

•  3-phase motor wiring diagram 6 wire
•  3-phase motor wiring diagram 9 wire
•  3-phase motor wiring diagram 12 wire

3-phase star delta motor connection diagram

This article does not show you the 3-phase star delta motor connection diagram. If you are interested in knowing the three-phase star delta starter motor connection schematic diagram, then you can visit the full document in another article on-

Star Delta Starter Line Diagram and Its Working Principle

In this article, there is no need for more literature.

So, let's go to show the motor terminals connection procedure.

Diagrams of the three-phase motor (6  leads)

Single winding

                                               Single speed

Single winding

           High-speed                                                   Low speed

Double winding

                    High-speed                                     Low-speed

Diagrams of the three-phase motor (9  leads)

Single voltage

Single winding

Double winding

Double voltage

Double winding

             Low Voltage                                          Higher Voltage

Diagrams of the three-phase motor (12  leads)

Single polarity

Single speed

Double polarity

High speed

High and low voltage three-phase is typically 230 volts or 400 volts 3-phase (in most of Europe and Africa). The motor has three stator windings (six connections) and can be wired in Star or Delta. In a star, the windings are connected to a phase, and the other ends are connected together to form a star connection. This is the high voltage or 430-volt 3-phase connection. As can be deduced from the connections, you have 430 volts across two motor windings at all times. In Delta, the motor windings are connected with the ends together, in the shape of a triangle. 

Why Electric Motors Contain 3/3/9/12 Leads? 

Electric motors can have 3, 6, 9, or 12 leads depending on their winding configuration and connection flexibility. These leads correspond to the internal coil terminations brought out for different voltage or phase arrangements.

Here’s a clear breakdown 

Lead Count	Configuration Type	Purpose / Application	Connection Options
3 Leads	Single-voltage, single-speed	Each lead connects directly to one phase (U, V, W). Common in small motors.	Fixed Delta or Wye internally.
6 Leads	Dual-voltage, single-speed	Two sets of windings per phase. Allows high/low voltage operation.	Can be connected in Wye or Delta, series or parallel.
9 Leads	Dual-voltage, single-speed (more flexible)	Similar to 6-lead but with separate neutral points for easier reconnection.	Low-voltage Delta or High-voltage Wye.
12 Leads	Dual-voltage, dual-speed or multi-configuration	Each winding end is accessible. Used in complex industrial setups.	Can be wired for series/parallel, Wye/Delta, or two-speed operation.

Engineering insight:

• The number of leads determines how the motor can be adapted to different supply voltages and connection schemes.
• 3-lead motors are the simplest but least flexible.
• 12-lead motors are used in advanced control systems where reconfiguration or speed control is required.