Star Delta Starter - (Y-Δ) Power & Control Wiring

Star Delta Starter - (Y-Δ) Power & Control Wiring.

                          Automatic Star/Delta (Y-Δ) With Timer For 3ϕ-Phase AC Motors

Contents List

1. Automatic Star Delta Starter (Y-Δ) With Timer Diagram & Installation Diagram
2.Operation & Working of Automatic Star Delta(Y-Δ)  Starter.
3.Star Delta Starter(Y-Δ)Power Diagram.
4.Control Diagram Of Star Delta (Y-Δ) Starter With Timer.
5.Wiring Diagram of Star Delta(Y-Δ) Starter With Timer.
6.Advantages & Disadvantages of Star Delta(Y-Δ)Starter With Timer.
7.Characteristics &features of Starter Delta Starter.
8.Application of Star Delta Starter(Y-Δ) .

IN This lesson, We will Learn & Understand the Star-Delta(Y-Δ) -Phase Induction Motor Starting Method by Automatic Star-Delta ((Y-Δ) Starter With Timer. With Schematic,Power,Control and Wiring Diagram as well as How Star-Delta Starter(Y-Δ)  Works and their applications with advantages.


1. Automatic Star-Delta Starter(Y-Δ) with Timer Wiring & Installation Diagram.

AUTOMATIC STAR-DELTA STARTER WITH TIMER

Details Of the working of Star-Delta Automatic Starter With Timer Wiring Installation. 

From the left you have Main Contractor With Pneumatic timer Because Your Main  Contractor is always  ON , In the Middle, You have Delta  Contractor With a thermal overload relay for motor protraction in case the motor Exceeds the current rating set on the thermal overload relay, on the right you have the star   ContractorWhich is the first  ON   Contractor With the main contactor.

When time reaches its time limit the star  Contractor OFF and the Delta Contractor   ON  and the running at full load.

2. Operation & working of Automatic Star-Delta Starter. 

The phase current flows to thermal overload contact through fuse, then OFF Push Button , ON push Burton Interlocking Contact 2,and then C3 this way, the circuit completed,as a result.

 1. Contactor coil C3  and timer coil (11) is ON at once and the motor winding then Connected in star . When C3 is ON , its auxiliary open links will be Closed and vise versa (i.e close link would be open) Thus C1 contactor is also ON and Three Phase supply will reach to the motor. Since winding is connected in star, Hence Each Phase will get the  √3 time less then the line voltage i.e..230 v Hence motor Starts Safely.

2. The close contact of C3 in the Delta line open because of which there would be no chance of activation of contactor C2 .

3. After leaving the push button, Timer coil 3 recitative a supply through Timer contact (Ia) , Holding contact 3 and the close contact 2 of C2.

4. When contactor 1 (C1) is ON then the two open contact in the line of C1 and C2 will be closed.

5. For the specific time (generally 5 to 10 second) in which the the motor will be connected in star, after that the time contact (Ia) will be open.

6. Contactor 3 (C3), will be OFF Because of which the open link of C3 will be closed (which is the line of C2 thus C2 will also ON. Similarly When C3 OFF .Then Star Connection of Winding will also open. and C2 will be closed. therefor the motor winding connected in delta. In addition, contact 2 (which is the line (C3) will open. by Which there Would not be any chance of activation of coil 3 (C3)

7. Since the  motor is connected in Delta now, Therefore each phase of the motor receive full line Voltage (400 V) and the motor will start to run in Full Motion. 

3. Star-Delta Starter Power Diagram.

Power Circuit Diagram Of Automatic Star-Delta Starter For 3-Phase Motor

Control Circuit Diagram Of Automatic Star-Delta  Starter with Timer for 3-Phase Motor

4.Advantages & Disadvantages of Star-delta Starter with Timer

Advantages:

• Simple Design & Operation.
• Cheaper Than Other Voltage controlling methods.
• Torque and Current Performance of the Star-Delta Starter is Well.
• It draws two times starting current of the FLA((Full Load Ampere) of the connected motor
• It reduced the starting current to one third (approximately) as compared to DOL(Direct Online) starter. 

Disadvantages:

• Starting Torque is also reduce to one-third because starter reduce the starting current to one-third of the rated current.(Line Voltage also reduced to 57%(1/√3))
• It requires Six leads or terminals Motor (Delta Connected)
• For Delta Connection, the Supply Voltage must be same as the rated motor Voltage.
• At Switching Time (from Star to Delta ), If Motor Does not Reach at least 90% of its Rated Speed, then the Current peak way be equals high as in Direct ON-LINE Starter (DOL), thus it may cause harmful effects on the Contactors Contacts, so it Would not be reliable.
• we may not use star-delta starter if the required (application or load) torque is more than 50% of the three phase induction motor rated torque.

5. Characteristics & Features of Star-Delta Starter

• The Starting Current is 33% of Full Load Current for Star-Delta Starter.
• The Peak Starting torque is 335 of Full-Load Torque
• The Peak Starting Current is 1.3 to 2.6 of Full-Load Current.
• Star-Delta Starter can Be used Only for Low to High Power 3-phase Induction Motor.
• It has reduced Starting Current & Torque.
• The 6 Connecting Cables Are Required for Motor Terminal Box.
• In Star-Delta Starter, Current Peak and Mechanical Load on Changeover From Star-Delta.

6.Application of Star-Delta Starter.

As we know the main purpose of Star-Delta Starter Is to Start the 3-phase Induction Motor in Star-connection While Running in Delta Connection. 

The End.