How to detect Line (Hot) and Neutral Reversed with the electronic circuit?

Armed with this understanding it should be very easy to decide just how you want to test a circuit. But for the life of me I can't imagine why anyone would need an automatic detector circuit to be active on the line at all times. When the wiring is installed THAT is when it's tested to make sure it's done right. What's going to change after that? Unless someone physically alters the wiring (or works on the line) nothing should change. And if someone DOES work on it - testing to verify the wiring was done correctly should be performed BEFORE restoring power to the equipment. But if you want an automatic system to monitor it - that's your prerogative.
3 phase protection is more common. We lost a phase in a storm and most of the stuff survived, but a few things did not and those things were very expensive to repair. So, 3 phase protection was added. That included mismatched voltages, phase reversal, missing phase, and timed loss and timed re-start. One event in 25 years or so. I don't think we had phase reversal. I think it was like 5 devices total. It wasn't cost effective to do it to ventilation and 36 heat pumps.
 

Tonyr1084

Joined Sep 24, 2015
7,853
3 phase protection is more common.
Leave it to me to think simplistically. Besides, the video the TS attached showed single phase. As to protection from phase loss or reversal - I'll have to take your word for it. I can imagine it being so, so.

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Oh, and does 3 phase have a neutral? I'm betting on it not having anything more than the three phases and a ground line.

[edit] On a 3 phase motor, if you swap two of the phases, doesn't the motor run the opposite direction?

BTW - I'm not trying to hijack the thread, so lets stay on topic please. Thanks.
 
Last edited:

MaxHeadRoom

Joined Jul 18, 2013
28,619
As to protection from phase loss or reversal - I'll have to take your word for it. I can imagine it being so, so.

Oh, and does 3 phase have a neutral? I'm betting on it not having anything more than the three phases and a ground line.

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Phase reversal is used in crucial situations such as remote pumping stations and elevators etc, 3 phase has a grounded Star neutral usually, if delta then other means of providing a neutral is done, but as last resort.
Max.
 

Tonyr1084

Joined Sep 24, 2015
7,853
I still think the TS is focused on single phase. Would be nice to get some clarification from the TH though. ARE we discussing single phase? Or are we discussing three phase?
 
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