Star/Delta Motor Circuit - The Main Circuit Breaker and Overload

Don't you know any power formula??

You can't.

It's easy but I don't give those sort of answer to people who post anonymously for simple questions.

This is silly. The full load current is on the motor plate. And everything else is in the appropriate national electrical standard. Hire a qualified Electrician who knows what to do!

For goodness' sake don't ask about cable sizing as well, as you'll become ridiculed. There's enough threads about cable sizing on here for one lifetime.

Disable the breaker and crank it up then let us know.

The sure sign for overload is when the white smoke comes out.

White smoke? Isn’t that when a new pope has been elected?

Every motor I’ve seen belching forth smoke it was a yellowy/brown colour and smells horrible.

We had a pool pump motor that belched out thick light green-coloured smoke under a locked-rotor test that was heavier than air and flowed off the test bench in great quantities.

We had to evacuate the whole building for the day because we knew that plastic smoke was really toxic.

That is because the wires always emit the complimentary color smoke. If they were yellow, the smoke would be blue, etc.

No, in our case the winding housing and much of the motor guts were made out of a cheap green plastic which once got up to a certain temperature went straight from a solid to a disturbing green gas. ALOT of disturbing green gas. Halloween-worthy special effect quantities.

Only one thing to do when events such as that arise - RUN!!!

That's what I did, grabbed the technician doing the test and jumped out the door closing it behind me (I swear the green cloud was trying to follow us out the door).

I had the orange cloud of mercuric iodide following me and the owner of one company I worked for that made the pellets that went into high intensity lighting for sports and TV studios. He had a congealed mass of pellets right were he was trying to "spin off" an ampule of about 1 Kg. The torch made the orange cloud. Very hazardous stuff, that.

It depends which colour the wires are, I am pretty sure about this!

Well, yeah, if the wires are the wrong color, then probably the voltage is wrong, too.

The problem with using the smoke test method of determining the OL setting is that it's very difficult to get all of the smoke back into the motor. I've never managed to get more than 75% back inside, so I end up buying a motor that is over sized by at least that much so that when I de-rate it for the missing smoke, I still have the proper amount of umph at he shaft.

Good point.

Go back to your textbook examples, and apply the formulae given. We don't do homework.

This is just one manufacturer & component range, Schneider have many useful design guides & all the information & components you need will be somewhere on their site ......

http://www.schneider-electric.co.uk/en/product-range-download/711-tesys-gv7?filter=business-1-industrial-automation---control#tabs-top

See for information:

http://escventura.com/manuals/ab_motorManagement_rg.pdf