Bus Tie Function in MCC 1

[Guinevere]

Dear All,
here i need a confirmation whether the bus-tie function in MCC is to:
1. connect 2 different rating busbar
2. as an protection,that if one of power supply is fail, the other one can still supply for respective motor.
3. as a connection limit between switchgear and motor controller?

Thanks all before...

Regards

 

[davidbeach]

4. Not nearly enough information supplied to make a determination.

 

[LionelHutz]

5. A homework question.

 

[Guinevere]

Hi davidbeach and lionelhutz
I think i didn't point my questions clear,sorry for that...
actually 3 points i pointed before is my understanding about bus tie, tried to surf in some link, but found not enough explanation on this one...

i know perhaps it's a stupid basic question, but
its function still blurr for me,
Perhaps you can help Me

Thanks a lot...

 

[LionelHutz]

A typical installation would have 2 transformers feeding 2 main busses. The tie switch would connect those busses together so that the installation could run off a single transformer.

 

[waross]

I'm with Lionel on this. Often the bus tie is not closed unless one of the feeders is opened.
Google this site for some discussions concerning protection issues when the tie is closed between two energized feeders.
You have it here:

2. as an protection,that if one of power supply is fail, the other one can still supply for respective motor.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Guinevere]

Dear All,
Thanks for the valuable answers,
it's concise but clear