Description
Star delta starters are the most widely used starters for the starting three phase induction motors. With Star Delta the motor is wired with a star connection for the starting time.
Once the motor reaches the required RPM, the connection changes over to a delta connection.
Star delta starters can start motors with star connecting stator windings. As soon as the motor reaches approximately 80% of its full load RPM, the connection will change into a delta connected stator winding.
Start Delta starters are a kind of reduced voltage starter. They are used to decrease the starting current of the motor without using an external source – such as a jump starter
This is one of the main advantages of these starters, as they typically have around 33% of the inrush current compared to a normal Direct on Line starter.
Star Deltas consist primarily of a TPDP switch which is the abbreviation for Triple Pole Double Throw switch. the TPDP switch swaps stator windings from star to delta.
Advantages of Star Delta Starter
- They are relatively inexpensive compared to VFD’s, Softstarters and external ramp up devices
- Minimal heat production,
- Reduction of starting current by nearly 70% compared to direct on line starting
- High torque per ampere production
Disadvantages of Star Delta Starter
- Starting torque is reduced to 1/3 of full load torque.
- A particular set of motors required.
Star Delta starters are most suited to work where the required starting current isn’t high and where the current draw must be kept to a minimum
Star Delta starters aren’t appropriate for use when high startup torque is necessary.
