Star-Delta Control Circuit

 Star Connection :

I(L)  = I (ph)

V(L) = √3 V(ph)

Line Voltage = Phase to Phase voltage

                           (R-Y, B-Y, R-B)

Phase voltage = Phase to Netural

                           (R-N, Y-N, B-N)

Where,

             Phase to Phase    - 400V

             Phase to Netural - 240V.

In star, we have Netural Phase Connection.

In star, winding each Phase winding has 240V.

Disadvantage :

   Voltage decrease in Phase.

Delta Connection :

                        V (L) = Vph

                        I  (L) = √3 Iph

             Line Voltage = Phase voltage

                                        each Phase has 400V.

In Delta we get more Voltage than star,

        R-Y = 400V       where, B as Netural

        Y-B = 400V       where, R as Netural

        B-R = 400V       where, Y as Netural.

In Delta, We don't have Netural Phase.

                We have to take from R,Y,B Phase.

Example :

How to find motor is in 1-¢ (or) 3-¢

   

Solution : 

    Single phase motor has 3 terminals.

Single phase motor has 3 terminals

1) 1st terminal as Phase

2) 2nd terminal as Netural

3) 3rd terminal as Auxiliary phase

1-¢ motor is not self starting, to make it self start we creating auxiliary phase with the help of series capacitor.

In 1-¢ motor their will be no star (or) delta Connection.

Three phase motor has 6 terminals

Star :

Delta :

- In Delta system, we don't use Netural.

- In Induction motor when switch ON high inrush current flow for 3 to 5 second (or) 7 sec.

Example :

Motor 10KW it's current.

    →10 × 1.9 = 19A.

It is used 5 times in a day - 19×5=95

Therefore, Current will be 95A.

Due to high current flow, the motor life will be decrease upto 50%.

So, it's decrease the high current we have to first start in 'STAR' connection then transfer to 'DELTA' connection.

Continuity Check :

                Continuity check is use to check the working of the winding.

3-¢ motor continuity check.

Star-Delta Control Circuit :

Star-Delta Timer :