Delta connection is an arrangement of three of same or different passive components. It is also called a mesh connection. The three passive element is connected with each other; the input supply is given through the two junctions of the element. Or the starting ends of the three phases or coils are connected to the finishing ends of the coil. When the connections are changed, the windings are re-distributed so that the motor has a different number of poles. If the high speed connection has 4 poles and the low speed connection has 6 poles, the high speed is 1.5 X the high speed. For a 6 to 8 pole change, the high speed is 1.33 X the low speed. Difference Between Star and Delta Connection What is Star Connection. In the start configuration, all windings have common point at the neutral end. Its structure is like a star and has a neutral wire. It helps to protect the overvoltages. In this configuration phase volts is 3 times less than the given volts For star delta starter,the basic function is to enable the motor to start and the motor windings are configured in a star formation to the supply voltage. The voltage applied for star delta starter to the individual motor winding is therefore reduced by a factor of 1√3 = 0.58 this connection amounts to approximately 30% of the delta values The standard is 63 frame up to 112 frame is 230v – Delta and 400v – Star. Above this frame size the voltage then is 400v – Delta and 690v – Star. This is due to the kW of the motors and the power required to run them. The only real contentious issue is that some motor suppliers make the voltage change on 100/112 frame sizes, others 132 Fig. 4. Delta winding reconnected in star. alent star (or in other words a star connected motor of the same power and voltage ratings) and the motor reconnected in a star connec-tion; for convenience they are referred to as motors A, Band C respectively. An important result from Table 1 is that the per unit im-pedances are equal for all three In a delta connection, there is no common or neutral point since load impedances are connected like a triangle. This can be seen in Fig. 3.5, in which line-to-line voltage V ab drops in impedance A, so current i a is higher than phase current i ab. Since impedance is the same, the power absorbed by the load in both connections—star and delta The star connection is shown in the diagram below: Considering the above figure, the finish terminals a 2 , b 2 , and c 2 of the three windings are connected to form a star or neutral point. The three conductors named as R, Y and B run from the remaining three free terminals as shown in the above figure. Here you can learn the fundamentals and operation of star-delta starters. When an induction motor is started directly online, it tends to draw a starting current ranging between 6 to 10 times its normal full load current. It can result in voltage sags. A star-delta starter can help to reduce this starting current by 33%. When using a different starting method (e.g., soft start, variable-frequency drive, or across-the-line), always connect the machine for run. Some machines will have 1-1, 2-2, 3-3, which will be a delta-run motor (see Figure 2). Also, some part-winding start motors are numbered incorrectly as 1-6, so keep in mind the starting method you’re using. PsCxnv.