Electric motor linkage is also known as “locking”. Three-phase motors can have 6 or 12 terminals each pair of terminals relative to a coil.
Star (Y) and triangle connections: Each three-phase motor coil must receive 220V in normal operation, unless it is a special high-voltage motor.
The 6-terminal motor can be connected in 220V or 380V; The 12-pin motor can be connected to 220V, 380V, 440V, or 760V. BALDOR VEM3555-57
The voltage with which the motor can be fed depends on the way associated with their coils. Such a bond can be star (Y) or triangle (delta) being that in triangle the coils receive the existing voltage between phases and in star the coils receive such tension divided by square root 3.
The motor coils of 6 terminals can be associated in triangle (to operate at 220V) or star (to operate at 380V or to from 220V). The 12-terminal motor coils can be different forms:
Uses Triangle connection for lowest voltage and star connection for highest voltage.