3 phase motor over current formula

[Scott48]

the apprentice is sitting his am2 and question is on his 3 phase motor which is 5.5kw what is the over current he dont deal with 3 phase what's quickest way to explain to work it out

 

[Pete999]

the apprentice is sitting his am2 and question is on his 3 phase motor which is 5.5kw what is the over current he dont deal with 3 phase what's quickest way to explain to work it out

Are you asking what current a 5.5KW would take? you should be able to help him there Scott.

 

[Scott48]

No the current per phase is obvious but there asking over current which if i remember is the current x 1.5 ?

 

[Pete999]

the apprentice is sitting his am2 and question is on his 3 phase motor which is 5.5kw what is the over current he dont deal with 3 phase what's quickest way to explain to work it out

Three Phase Current - Simple Calculation - http://myelectrical.com/notes/entryid/8/three-phase-power-simple-calculations

 

[Pete999]

Three Phase Current - Simple Calculation - http://myelectrical.com/notes/entryid/8/three-phase-power-simple-calculations

Overload relay setting and calculation - https://www.electricneutron.com/motor-control/overload-relay-setting-and-calculation/

 

[DavidSpark]

Hopefully this will help.

 

[DPG]

The typo in the title doesn't inspire much confidence in that document.

 

[DavidSpark]

Never even noticed that haha! Thankfully it wasn't me who typed it up, but I think the theory behind it is sound enough.

 

[Lucien Nunes]

I think the theory behind it is sound enough

Anybody care to guess which P they think they mean?

 

[Bobster]

Not sure why setting the overload +10% is still being taught.

That's not been applicable for a long while.

 

[DavidSpark]

Anybody care to guess which P they think they mean?

I'm sure they mean part P. Everyone knows I x V x p.f. = part P

 

[davesparks]

set it to the flc as detailed on the motor rating plate.

 

[Lucien Nunes]

I think the trick here is that they aren't given the flc for the test, only the motor power rating (it's not a real motor IIRC, just a terminal box). But on the basis of post #6 the power quoted is not given as normal on a motor (output power) but the electrical input power. Or whoever wrote that suspect-looking page was even more barking.

 

[Pete999]

I'm sure they mean part P. Everyone knows I x V x p.f. = part P

Pete999?