3 Phase Voltage Measurement without neutral using Microcontroller

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#1 21677243 05 Apr 2017 11:46

Dilip G R Dilip G R

Anonymous

Post #1
21677243 05 Apr 2017 11:46

I'm developing 3phase star-delta starter but I'm facing difficulty in measuring 3phase voltage using microcontroller, I need a circuit to measure 3phase voltage and display it in LCD using microcontroller.
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#2 21677244 05 Apr 2017 14:11

Dean Franks Dean Franks

Anonymous

Post #2
21677244 05 Apr 2017 14:11

Use three resistors (value depends on voltages). Connect one end of each resistor to each leg of the 3 phase circuit and connect the other ends together. The connected node is your neutral. You can tie this to digital ground (assuming low voltage starter), and use resistor dividers between each phase and the neutral leg to scale the 3 phase voltages to whatever your ADC wants.

Dean
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#3 21677245 05 Apr 2017 19:31

Kevin Angelo Ma Kevin Angelo Ma

Anonymous

Post #3
21677245 05 Apr 2017 19:31

Check this out.. http://engineerexperiences.com/3-phase-voltage.html
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#4 21677246 06 Apr 2017 12:33

Dilip G R Dilip G R

Anonymous

Post #4
21677246 06 Apr 2017 12:33

I already tried this..I don't have neutral or ground point
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#5 21677247 18 Jul 2017 13:42

James Ruggieri James Ruggieri

Anonymous

Post #5
21677247 18 Jul 2017 13:42

If your voltage source is delta - then you would not have a neutral. You could "derive" a neutral using transofrmers if you needed to. In wye configuration, phase to neutral voltage is the phase voltage divided by the square root of three. However, you state that you want to measure phase voltage which is across the line phase to phase -- you do not need a neutral to measure phase-to-phase voltage.
#6 21677248 17 Aug 2020 13:25

Lalit Dhingra Lalit Dhingra

Anonymous

Post #6
21677248 17 Aug 2020 13:25

Thanks Dean.I liked this idea.One question though, would that not make negative voltages being fed to ADC?
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3 Phase Voltage Measurement without neutral using Microcontroller

3 Phase Voltage Measurement without neutral using Microcontroller

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