Table of Contents
- 1 Which contactor start first in star delta starter?
- 2 When the motor is switched to star position through a star delta starter the stator current will become?
- 3 What is the difference between star delta starter and DOL starter?
- 4 What is the function of a timer in a star delta starter?
- 5 What is a star Delta switch?
Which contactor start first in star delta starter?
The ON push button starts the circuit by initially energizing Star Contactor Coil (KM1) of star circuit and Timer Coil (KT) circuit. When Star Contactor Coil (KM1) energized, Star Main and Auxiliary contactor change its position from NO to NC.
When the motor is switched to star position through a star delta starter the stator current will become?
Firstly, the stator winding is connected in star and then in Delta so that the starting line current of the motor is reduced to one-third as compared to the starting current with the windings connected in delta.
Why interlocking is used for the contactors?
What is Contactor Interlocking? When an electrical circuit has two contactors and only one of them needs to be turned on at a time then the interlocking system is used. The interlocking system ensures that only one contactor can be on while another one will be in off condition even if we try to manually on.
How do I select a star delta contactor?
Size of Star Contactor =33\%x13 = 4 Amp. Size of Main Contactor (Starting-Transition-Running) = 58\%X Full Load Current (Line). Size of Main Contactor =58\%x13 = 8 Amp. Size of Delta Contactor (Running Condition) = 58\%X Full Load Current (Line).
What is the difference between star delta starter and DOL starter?
In the DOL starter, it is possible to start a motor with a simple circuit. This can be further explained that in a Star-Delta starter, the motor is started as a star connection and when the motor starts running the connection is changed to the delta. With star connection, the motor takes times less voltage.
What is the function of a timer in a star delta starter?
The function of a timer in the star-delta starter is to switch contactor from star to delta after attaining sufficient speed up to 90\% of motor full speed. Fuse unit is used to protect the motor from over current or short circuit conditions.
How to start a large motor using star delta starter?
To start a large motor we need a reduced voltage starter, to limit starting current. Star delta starter is a reduced voltage starter that applies 1/√3 voltage during the starting time. During the starting time of star delta starter, Main contactor and star contactor remain in the close state and complete power circuit.
What is the difference between main contractor and Delta contactor?
There are two contactors that are close during run, often referred to as the main contractor and the delta contactor. These are AC3 rated at 58\% of the current rating of the motor. The third contactor is the star contactor and that only carries star current while the motor is connected in star.
What is a star Delta switch?
Star Delta Switching. Star-delta (wye-delta) starting continues to be used for switching on 3-phase induction motors. When this type of connection method is used, the starting current is reduced to 1/3 of the current required for direct switching.