[SOLVED] Measuring 3-phase AC voltage using voltage divider circuit

Heavenlyrider said:

Hi,

can any one give me the circuit for measuring 3 phase voltage with reference to Neutral?. i tried all changes that mentioned above. but still i am not getting a stable output.

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I believe this is how the 3 AC sources are arranged. (I forget if it's called the delta type or the Y-type.) To read their voltage you can choose a node between any 2 sources, and call that arbitrary ground, and get a sensible amplitude reading for those 2 sources.

However you cannot attach the third source to ground. To take the third reading you must take the difference between the other two readings. You must use their unaltered sinewaves. Subtract one from the other.

Outputs 1 & 2 are direct readings (referenced to 0V ground). To get the third reading, the simulator provides a 'scope probe' which derives the difference between Out1 & Out2. Notice the scope traces show correct waveforms. Amplitude is correct and the 3 phases are staggered 120 degrees.

BradtheRad said:

I believe this is how the 3 AC sources are arranged. (I forget if it's called the delta type or the Y-type.)

Click to expand...

The connection is delta; but one node is connected to ground. (it is not a problem here but in a real case, the nodes in the delta connection are floating)

(the problem will appear if another user, using the same three phases, connects the delta in a similar fashion, but connects a different note to ground)

Hi, i used below thread to design my voltage measuring circuit and its working. so, i am marking this thread as solved.


here is the link: https://www.edaboard.com/threads/355515/