3 Phase Voltage Help

Thread Starter

dmarullo3

Joined Mar 26, 2013
2
Looking for some help with a hw problem. Having some trouble with AC phase relationships. In this problem im having trouble determining the phase sequence. I think i can get the angle from the frequency the three voltages are at. Help would be greatly appreciated. Ive attached an image of the problem.
 

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Paulo540

Joined Nov 23, 2009
191
If Vb -> Vc -> Va, you can always reconfigure it to be a b c. Might make it easier.

Also, it might help to note where the zeros cross on the chart instead of the peaks.

I assume you are able to do the RMS and leg voltage calcs at this point. ?
 

Thread Starter

dmarullo3

Joined Mar 26, 2013
2
yes i have the RMS voltages, i know the between the three voltages they are 120 deg apart for the phase voltages and the line voltages are the same only separated by 30 deg.
 

panic mode

Joined Oct 10, 2011
5,250
there are only two sequences - abc and bac
since this is periodic, it repeats over and over so abc sequence looks like
abcabcabcabcabc...

you can see inside it 'bca' so this is 'forward' sequence

if you swap any two phases, you get bac:
bacbacbacbacbac...

btw. 'bac' is similar to *back* (or reverse) sequence
 
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