 # 3 phase 3 wire algorithm

Dear all.

I have attached schematic for reference. I have doubt related to calculating and printing some data.
I have 3 phase 4 wire system
if i give 3 phase with 4 wire i could able to read analog channel from A0/A1/A2/ and convert them to display line voltage

Now i wanted to measure like this

condition 1 : Where i could use separate line R,Y,B in this case Line to Neutral ,Line to line voltage should display vline=Sqrt(3)*Vphase voltage

Condition 2:Assume Rphase being shorted to yphase/bphase where y/b phase connection are removed. Rphase only supplying voltage to y/b phase in this phase angle will be 0 degree instead of 120deg. Now how can i measure such away that Line to neutral will be showing 230v but line to line will be showing 0V since phase angle is zero

Is there any common ckt that uses 3 phase 3 wire and 3phase 4 wire
any simple algorithm to measure voltage when setup changed?/

Hi,
Ops diagram.

Tom... Can someone suggest me idea here or equation here

1. I wanted to measure line to line and line to neutral .How can i measure ?is there any formula??

2. assume in 3 phase , i have shorted R-phase to Y and B phase line input . In this case how i could able to measure Line to line and line to neutral voltage.

Is there any equation available.

AJITnayak:
Can someone suggest me idea here or equation here

1. I wanted to measure line to line and line to neutral .How can i measure ?is there any formula??

2. assume in 3 phase , i have shorted R-phase to Y and B phase line input . In this case how i could able to measure Line to line and line to neutral voltage.

Is there any equation available.

could not fully understand what you are trying to achive with your 3-wire / 4-wire but it sounds like the equations used for "Star/Delta Transformation and Delta/Star Transformation" should be able to help you here

Hello AJITnayak
In your schematic you have some electronics attached to the neutral, and a connection from that electronics to what looks like (it goes off the side of the schematic) ground. I would expect ground and neutral to be connected together somewhere, so that connection shorts out some of the electronics. I would also expect current to be flowing in the neutral if the load is not balanced between the 3 phases, inducing a voltage drop across the resistance of the neutral wire, making a small AC difference between neutral and ground. Are you aware of this? Am I reading the schematic incorrectly?

condition 1 : Where i could use separate line R,Y,B in this case Line to Neutral ,Line to line voltage should display vline=Sqrt(3)*Vphase voltage

If you mean that phase to neutral voltage * square root of 3 = phase to phase voltage, then yes, that's correct. Was there a question?

Apart from that I'm struggling to understand what you want to know. You will be measuring the voltage and phase of each of the 3 phases with reference to neutral, the above formula tells you the phase to phase voltage.

To measure R-phase with respect to Y-phase, you need an isolation transformer with primary connected to R and Y and secondary connected to Arduino analog pin and GND.
Like the blue one on this module.
https://www.amazon.com/WINGONEER-Single-phase-active-voltage-transformer/dp/B071HV4S5M/ref=sr_1_29?keywords=voltage+sensor&qid=1564628054&s=gateway&sr=8-29

Assume i have made changes made as per suggestion.I have used voltage transducer or voltage transformer in place of my ckt.It will sort out my problem related to isolation etc,

But arduino analog channel still will be getting analog voltage from 0-5v which we Converting to AC voltage equation

I have attached my ckt here. Now assume Rphase is alone connected Y and B [hase are removed. The phase angle between R to other phase will be zero, where other case it will be 120 degree phase shift.

How can i differentiate my calculation here.

Equations.pdf (221 KB)