Main Mc Control In Star Delta Starter

[AB2005]

Hello All!

 

Good return after a happy Christmas.

I am confused about main contactor control arrangement in star delta starters. We have purchased a new starter which contactor control method is differing from old starters in Japanese machines. Please check the circuit diagrams and advice me.

Thanks for any input.

 

Star Delta Circuit diagrams

[marke]

Hello AB2005

 

I am unable to open your diagrams, there appears to be a problem with your link.

 

There are two methods of configuring the contactors in a star/delta starter.

One, the most common configuration is to use equal sized main and delta contactors with the inputs connected in parallel. These contactors are rated at 57% of the motor rating.

 

The alternative connection is to use a full rated contactor for the main contacor and feed the delta contacor from the output of the main contactor. The main contactor must be rated at the motor current and the delta contactor rated at 57% of the motor rating.

 

Both connections are valid, but the first option is cheaper and so is normally used.

 

Best regards,

[AB2005]

I am unable to open your diagrams, there appears to be a problem with your link.

Dear Sir,

 

I don't know why this page is not opening, here is opening from my PC. However, I have saved this Excel file in another link. Please check it and help me if this second link would not open because this is my first experience.

Star Delta Circuit

 

[marke]

Hello AB2005

 

When I click on that link, I get the following:

Firefox can't find the server at bcvrf.yahoo.com.

Best regards,

[AB2005]

Hello AB2005

 

When I click on that link, I get the following:

Firefox can't find the server at bcvrf.yahoo.com.

 

Best regards,

Dear Sir,

 

I have also tried to attach this file with reply by using "File Attachment" option after Zip the file but following error occurred;

 

"THE FOLLOWING ERROR(S) WERE FOUND

The requested file upload failed because suitable permissions have not been enabled on the 'uploads' directory. Please contact the board administrator and inform them of this error"

Please help.

[marke]

Hello AB2005

 

The attachments now works OK, it got messed up with the server switch and was rather hard to find.

 

Best regards,

[AB2005]

The attachments now works OK, it got messed up with the server switch and was rather hard to find.

Thank you sir,

 

Please find the attachment. I am waiting for your valuable comments about our newly purchased motor starter control circuit.

StarDelta.zip

[marke]

Hello AB2005

 

I don't know any "sir" here, I am Mark and perhaps I can help.

 

I have looked at your two diagrams and I prefer the circuit on the recently purchased Motor Starter.

With a star/delta starter, there is a special timer used which has a delay between the star contactor opening and the delta contactor closing. If you do not have this delay, you will have problems.

This delay will cause the main contactor to open and then close again on the star to delta transition and double the number of operations of this contactor. This will mechanically shorten the life of the contactor.

I have always used the second option.

 

Best regards,

[AB2005]

Hello AB2005

 

I don't know any "sir" here, I am Mark and perhaps I can help.

Dear Marke,

 

Actually, I respect you because of your experience. That is why I add "Sir" with your name.

 

I have looked at your two diagrams and I prefer the circuit on the recently purchased Motor Starter.

With a star/delta starter, there is a special timer used which has a delay between the star contactor opening and the delta contactor closing. If you do not have this delay, you will have problems.

This delay will cause the main contactor to open and then close again on the star to delta transition and double the number of operations of this contactor. This will mechanically shorten the life of the contactor.

I have always used the second option.

 

 

Thank you for your comments. Both circuits contain same start delta timer. Therefore, delay between the star contactor opening and the delta contactor closing is present in both circuits.