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### Topic: Three phase sequence reversal detection using aruino uno (Read 177 times)previous topic - next topic

#### Samvil

##### Oct 08, 2019, 08:18 am
Hello,
I am trying to detect phase sequence of  three phase power using arduino. I have three phase digital pulses to the input of the arduino board. The base is to determine the reference point and measure the rising time of the other remaining 2 phases pulses.
How do I set the reference point i.e when phase at pin when start to rise?
How do I determine when the second phase pulse starts to rise?
How do I know when phase reversal has occurred?

#### dougp

#1
##### Oct 08, 2019, 08:03 pm
How do I set the reference point i.e when phase at pin when start to rise?
IDE -> file/examples/digital/stateChangeDetection

In truth the first five demos are essential knowledge.

How do I determine when the second phase pulse starts to rise?
Make a timestamp copy of millis() on first phase rise and one on second phase rise then subtract.

How do I know when phase reversal has occurred?
Search the web for 'quadrature encoder'.  The waveforms from an encoder are very similar to your 3-phase signals.  Do a quadrature decode on each pair of phases.
Everything we call real is made of things that cannot be regarded as real.  If quantum mechanics hasn't profoundly shocked you, you haven't understood it yet. - Niels Bohr

No private consultations undertaken!

#### hammy

#2
##### Oct 08, 2019, 09:50 pmLast Edit: Oct 08, 2019, 09:53 pm by hammy
You are going to need some signal conditioning as the Arduino can't work with negative voltages . If you used small transformers plus three comparitors  set to some fixed voltage all you need to do is look at the order the 3 comparitors trip to see whether a phase is reversed (and coming up in the wrong sequence).
Use one phase ( any one, say blue) as the reference , then all you need to know is if , say the yellow or red phase comes next .

#### JCA34F

#3
##### Oct 09, 2019, 02:39 pm
Quote
I have three phase digital pulses to the input of the arduino board.
Where do these pulses come from? What is their voltage and polarity?

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