- #1
chris_MH
- 1
- 0
Hello, I have come to this forum as I don't believe what i am being taught to be entirley accurate and need some clarity on a question (not an exact answer, this is not homework)
To begin, I believe the person 'teaching' my subject is not up to standard as when our final topic of three phase motors came about, instead of teaching the construction, starting principles of operation, poles ect, he gave us a hand out printed froma random website.
The words 'stator', 'rotor' and even how the line windings influence the poles are never mentioned, its more of a case of 'here read this and get on with it'. This has repeated through out my course, for example, a new formula appeared today
power = resistance x voltage I am being taught so how am i meant to know right from wrong ? anyway onto my question, now you know what I am dealing with!
I quote
'motor rated 440v 3000 watt, however one winding has become bad drawing an extra 50% of its current load.
Using three phase theory produce a representational graph to show the effects of an unbalanced motor entering the relevant information'
Basically what my teacher said was this...
Two phases will remain unchanged in terms of their current, frequency and power. He said the output will be current and the input will be 240V voltage (UK) (?)
The third phase however will be out of phase, the current unchanged.
After soooo many months of trying to teach myself and ignore what I am told I can not trust this person, simple errors such as power formula being wrong (not the one above), not being taught anything relevant to assignments, not being taught anything at all at times and blaming us for not knowing it.
Is what I am told true?
To begin, I believe the person 'teaching' my subject is not up to standard as when our final topic of three phase motors came about, instead of teaching the construction, starting principles of operation, poles ect, he gave us a hand out printed froma random website.
The words 'stator', 'rotor' and even how the line windings influence the poles are never mentioned, its more of a case of 'here read this and get on with it'. This has repeated through out my course, for example, a new formula appeared today
power = resistance x voltage I am being taught so how am i meant to know right from wrong ? anyway onto my question, now you know what I am dealing with!
I quote
'motor rated 440v 3000 watt, however one winding has become bad drawing an extra 50% of its current load.
Using three phase theory produce a representational graph to show the effects of an unbalanced motor entering the relevant information'
Basically what my teacher said was this...
Two phases will remain unchanged in terms of their current, frequency and power. He said the output will be current and the input will be 240V voltage (UK) (?)
The third phase however will be out of phase, the current unchanged.
After soooo many months of trying to teach myself and ignore what I am told I can not trust this person, simple errors such as power formula being wrong (not the one above), not being taught anything relevant to assignments, not being taught anything at all at times and blaming us for not knowing it.
Is what I am told true?