Star/Delta Connections – Used for the 3-Phase Motors

There are two ways to connect a 3-phase electrical motor. The first one is the star which is denoted in Y and the next one is delta that is denoted in A. Well, there are also some winding phases associated with a 3-phase electrical motor and they can be denotes as U, V as well as W and series of them can be presented in this format U1-U2, V1-V2, as well as W1-W2. In case of the Y or star connection, the winding phases of the same motor can be joined together in order to form the zero point and this mostly looks like the star Y.

Star connection of motor

For example, on a motor plate this value is 690/400 V. In this case, star connection can produce higher voltage and the delta shows the low level of voltage. Well, the current that can be mentioned on motor plate can even show the lower value for star connection as well as higher value for delta connection.  As per this rule, the main supply connection to the 3-Phase motor can have the terminals which are marked like U, V as well as W. And at the same time, phase sequence can be marked as L1, L2 as well as L3. This suggests the 3-phase motor will start rotating clockwise from drive end that is marked as D.

Delta connection on electrical motor

If you wish to make the 3-phase motor rotate in an anti clockwise motion, then 2 from the 3 conductors attached to the motor or the starter can be switched. To get a better idea about this, you can check the function of a cooling fan and look for it when it rotates in an anti-clockwise motion.
In some cases, the dual starter is taken that connected the terminals of the motor directly to function as per the power supply. In this case, the motor can acquire full flow of voltage due to the power supply. Due to this reason, high starting flow of current can occur through a motor. Well, this sort of starting is just perfect for those motors which are small and their capacity remains below 5 hp. In some cases, the reduced-voltage starter is employed for the motors that are of above 5 hp. The generation of reserve power and the reliability of power supply dictate the real use of the reduced voltage. It also dictates the fact that starting current should not be reduced for the induction motors. However, the voltage flowing for these motors can be reduced to obtain better results.  It can be accomplished through star delta starter, autotransformer starter and resistor starter.

Star-delta connection with loads (coils in motor)

As far as the star delta starters are concerned, these are known as the most usual ones used for reducing the voltage for the 50 hertz world. They are also known as the Wye and Delta starters as per the 60 hertz world. These are basically used in order to reduce the starting current that is applied for the motor during when it starts. This is done to reduce the disturbances that can arise due to the interference in the supply of electricity.