I need your assistance on three phase systems.When the phase sequence changes some inverters ,particularly victron inverters in a 3phase set up do not allow the grid to pass through them and the display phase rotation errors.The inverters can accept this to pass only when you go into the device list -quattro inverter - advanced settings then Redetect the system.
There is a way to prevent this and is the use of V3E/N Reletek relays.Can someone who has done this advise me on the wiring of the system to the already existing 3phase set up.
I know that people who do power for big music shows often have a switch to swap two phases, because they cannot always count on things being wired correctly on the stuff they rent.
It is simple enough. You just need to swap any of the two phases. Typically L2 and L3 is swapped. Doesn’t matter if your end doesn’t match the upstream “labeling” of the phases, as long as the rotation is correct. Any DPDT kind of switch should be good for that.
I don’t know the product you reference, I can unfortunately only relay this generic information, which I hope helps.
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Thanks @plonkster I have attached the spec sheet for the product that I am referencing.I have seen it used instead of ordinary contactors.
The spec sheet says the Output is SPDT (single pole double throw), so I don’t think it is possible to use this without a contactor.
Just to be sure: Is your plan to automatically swap the phases? This relay seems to also detect out of bounds voltage conditions, as well as having a startup delay. It appears to be meant simply as a protection relay: Turn the supply off if it isn’t correct.
@plonkster yes I am planning to automatically swap the phases so that the inverters won’t show phase sequence errors and allows power to flow under this condition
My concern is that with this product, it will pull in the contactor for out of bounds voltages, lost phases, and phase rotation.
I can imagine a product like this working, if it did only phase-rotation monitoring. You’d wire a DPDT contactor to it, using the same method used to reverse direction on a 3-phase motor. An error condition from the monitoring device would then pull in the contactor and swap the direction.
I just don’t like that it will also do it on other error conditions. That’s not what you want.
There are dedicated “phase correction relay” products. I just can’t seem to find any locally.
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Personally I would not do this. You need a device that is rated for this sort of thing - to prevent an accidental bridging of two phases. Perhaps an approved ATS would be sufficient, but I don’t know. I do know that normal relays and contactors won’t make the cut.
I think if you used two three-phase contactors with a mechanical interlock between them, as is often used for direction control on three phase motors, that would be okay. But you still need a device that checks for phase rotation to switch the contactors.
You could of course use TWO of them. The first one switches the phases around, the second one checks that what comes out of the first one is correct and connects the supply. But now you’re talking THREE 3-phase contactors and TWO monitoring relays 
Yes, this device would seem to protect against a host of conditions where the standard action would be to trip the supply.
( I have used a similar type relay in the past on a 3 ph borehole pump, and found that particular device unreliable at the expense of 3 pump motors, so I will not use it again).
But besides that, there are other flaws in this thinking, triggering a rotational reversal, for different conditions ( Undervoltage or loss of phase say) would probably result in more harm than good.
Then there is the act of swapping two phases on a running machine (this can be done), but it MUST be a “break before make” circuit. This is so important that it uses 2 mechanically interlocked contactors. as a unit like this:
Then remember you will have to deal with a current spike as it happens, akin to what happens with some washing machines ( that throw inverters a wobbler).
Now, to get the issue, phase rotation doesn’t just change willy-nilly on a permanent plant. If you have a mobile unit that has to deal with multiple locations, yes then I can understand this situation.
I have seen the following deployed on a unit before:
A permanent mechanical ( break before make) switch integral to the supply circuit, that is selected prior to energisation.
(something like: L1-L2-L3 … OFF… L1 -L3-L2)
The desired phase rotation is confirmed with a phase rotation meter at a test point prior to switching on. And it stays at that selection for the duration of its residence.
This allows the mobile part of the plant to be deployed in places where the phase rotation has to be matched.
Even so, phase rotation is not the be-all and end-all. Frequency must match as well as phase displacement.
But a Victron inverter is reactive to the system and can match phase displacement and frequency (within limits)
Don’t think a standard supply can do this, though:
Phasing is a serious business.
3 phase transformers can also have phase shift HV to LV, ( this is called a transformer’s vector group) so for example, a YY0 and a Yd3 supply may NEVER be in phase despite having the same phase rotation.
There are a whole host of vector groups, but this illustration should indicate what I mean:
Here are a YY0, Yd1,Yd11 & YY6 for illustration purposes:
Keep in mind that there is a chain of 3ph transformers upstream from two independent supplies that are hoping to be phased.
There are other considerations that I won’t go into.
A guy I know who has a company called Eventpower builds portible DB’s for the event industry.
If needed I can ask him how he does the rotation, if I remember some of his DB’s have this feeture, but you actually have to insert a key for it to work, so that not just any junior techie with itchy fingers can do it.
Yes, the worst fault you can get is a 3ph 180-degree out-of-phase paralleling.
Literally, twice as bad as a 3ph to Earth fault.
The switchgear will probably not be rated for it.
So yes there should be extra precautions.
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