230VAC UPS wont run on 230VAC Line to Line

[pathfinders]

Im operating in philippines, where mny buildings use a 230V delta system, 230V line to Line, no ground.
so the available UPSs here are 230V AC.
I purchased alot of relatively expensive Vertiv Edge 1000 line interactive UPSs for some projects, adn am very very upset to find it telling me that i have reversed phase and neutral on its screen, its giving me that as an error, and refusing to operate as a UPS.
It can only do one of the following but nto both.
Charge its batteries, or
power the output fromt he batteries.

It refuses to turn on its output and accept power frm the mains becasue of htis error.

I feel a bit ocnned, as its for sale in this country and the standard electricity in this country is 230V Hot to Hot.
I was under the impression, that pretty much all devices on earth are safe to use Line to Line unless its chassis is bonded to what it thinks is its neutral conductor. thats not the case with theis vertiv. I didnt die plugging it in, while touching it, firmly on the ground, so its not protecting me from anything, its jsut seemingly a device sold in a country that it cant operate in.

Is ther some common known method of converting single phase line to line to some kind of line to neutral?
I cant quite wokr my head around what kind of transformer that would be. Im gutted and i pretty much give up, my boss is going to kill me, these werent cheap UPSs.

 

[augie47]

Their technical specs are a bit misleading. All the ones I saw reference 230v and not 120v. The only clue is the picture shows 120v receptacles.

 

[ruxton.stanislaw]

Is ther some common known method of converting single phase line to line to some kind of line to neutral?
I cant quite wokr my head around what kind of transformer that would be. Im gutted and i pretty much give up, my boss is going to kill me, these werent cheap UPSs.

You would need an isolation transformer, if not some hacky modification to the UPS (not recommending this).

Their technical specs are a bit misleading. All the ones I saw reference 230v and not 120v. The only clue is the picture shows 120v receptacles.

Around the world, NEMA 5-15R style outlets are used for dual voltages.

 

[augie47]

You would need an isolation transformer, if not some hacky modification to the UPS (not recommending this).


Around the world, NEMA 5-15R style outlets are used for dual voltages.

with that in mind, again looking at their tech sheets, you would think it would be fine on a 230v no neutral system.

https://www.vertiv.com/49a983/globalassets/products/critical-power/uninterruptible-power-supplies-ups/vertiv-edge-ups-br-en-ap-v1.pdf

 

[ruxton.stanislaw]

The IEC 60320 input connector that the UPS specification sheet references has a polarised connector and the original poster mentioned the UPS is giving an error about reversed neutral and phase. It is more than likely that the UPS has a schematic with similar functionality to those cheap plug-in outlet testers to detect that the neutral/phase wiring arrangement is correct. In the case of a three wire delta system, no matter which way you wire it, both phases will appear to have capacitance to ground, unless it is a corner grounded system or has something more complicated like a grounding transformer.

In theory, a hacky and not recommended way to fix this would be to "corner ground" one of the phases to the UPS - connect one of the phases to the ground... Do not do this though, it is unsafe and asking for trouble. Also, do not do this; another inadvisable fix would be to modify the schematic of the UPS, so the part of the circuit that detects the neutral voltage to ground conductor is no longer connected or zeroes out somehow, if possible. I am explaining these fixes to help you understand the problem. The correct thing to do is below:

A much safer way is to obtain a 230v isolation transformer and ground the neutral side of the secondary properly. Connect the UPS with the
grounded polarity intended by the manufacturer. Appliances you plug into the UPS will be safer to use that way as well. I would also recommend adding RCD devices to your systems where possible for added safety.

 

[pathfinders]

yeh bugger ok, i think that idea of an isolation transformer makes sense.
RCD is out of the question, im running telco gear, critical enterprise telco gear at edge sites, where online UPS is too much of a hassle due to battery reliability in the hot humidity. line interactive was the way to go but yeh, the local utiltyi privders distribute WYE-DELTA. Crazy Country.How big would something like this be, and what am i searching for?
Another foreigner owned company upstairs from my office who knew nothing actually approached me a year or so back asking me for advice for a similar issue, asking how we installed our UPS, as he was shokced to learn the building didnt have a neutral. That was easy because his was a 3Phase input UPS, and it seems very simple to transform 3Phase Delta back to 3Phase wye, but not so simple for single phase. i cant work out in my mind how a bunch of windings would do that... wierd.

 

[pathfinders]

actually i can see how adding in an isolation transformer might generally help with nuiscance tripping of an RCD if the RCD was in front of the Iso xfrmr. but wouldnt it then be pointless and only provide safety to the transformer lol.

 

[ruxton.stanislaw]

actually i can see how adding in an isolation transformer might generally help with nuiscance tripping of an RCD if the RCD was in front of the Iso xfrmr. but wouldnt it then be pointless and only provide safety to the transformer lol.

My thought for the RCD is to protect circuits that humans interact with the most; think a kitchenette, washroom, office computers etc. You may wish to exclude the UPS and other critical systems from it, if there is no law or code requiring such protection.

yeh bugger ok, i think that idea of an isolation transformer makes sense.
RCD is out of the question, im running telco gear, critical enterprise telco gear at edge sites, where online UPS is too much of a hassle due to battery reliability in the hot humidity. line interactive was the way to go but yeh, the local utiltyi privders distribute WYE-DELTA. Crazy Country.How big would something like this be, and what am i searching for?
Another foreigner owned company upstairs from my office who knew nothing actually approached me a year or so back asking me for advice for a similar issue, asking how we installed our UPS, as he was shokced to learn the building didnt have a neutral. That was easy because his was a 3Phase input UPS, and it seems very simple to transform 3Phase Delta back to 3Phase wye, but not so simple for single phase. i cant work out in my mind how a bunch of windings would do that... wierd.

Some UPSs might not have that neutral/live check. It sounds like a higher quality unit to have that engineering consideration. With technology hardware, it may be beneficial, such as reducing interference, to have a properly grounded system. The isolation transformer should be at least equal to the KVA rating of the UPS; probably a bit larger like 125% of the rating so it does not have to run too hot.

One other system that you could consider as an upgrade for the entire building is a grounding or zigzag transformer. Perhaps you could get the other tenant(s) on board with it. https://en.wikipedia.org/wiki/Grounding_transformer That will give you a proper ground in the delta system. If sufficient current leaks to the ground wire in this case, the RCD will trip right away. If you currently have an ECG and a short to a phase occurs, what you have is an inadvertently corner grounded system which allows for a lot of potential safety issues and interference.

 

[pathfinders]

My thought for the RCD is to protect circuits that humans interact with the most; think a kitchenette, washroom, office computers etc. You may wish to exclude the UPS and other critical systems from it, if there is no law or code requiring such protection.


Some UPSs might not have that neutral/live check. It sounds like a higher quality unit to have that engineering consideration. With technology hardware, it may be beneficial, such as reducing interference, to have a properly grounded system. The isolation transformer should be at least equal to the KVA rating of the UPS; probably a bit larger like 125% of the rating so it does not have to run too hot.

One other system that you could consider as an upgrade for the entire building is a grounding or zigzag transformer. Perhaps you could get the other tenant(s) on board with it. https://en.wikipedia.org/wiki/Grounding_transformer That will give you a proper ground in the delta system. If sufficient current leaks to the ground wire in this case, the RCD will trip right away. If you currently have an ECG and a short to a phase occurs, what you have is an inadvertently corner grounded system which allows for a lot of potential safety issues and interference.

so, one of the first things i did when i started working here, was added in our own ground pit out the front as an auxiliary telco ground, using the BICSI standards for TGMB as a guide. Spent quite a bit of money on it with pure copper everythign and propper irreversible crimps etc, I bonded everything and grounded it all to a new bus bus bar in the server room and that all goes to that ground pit. That other tenant heard about it, missinterpretted it as something that he needed, and thought I ( some foreigner) had managed to install a neutral wire so he was asking me for access to it LOL.
So fast forwards a couple of years, and im in the same boat as him, just with single phase not 3 phase.
So im not 100% on board with how a transformer for this scenario woudl work or what it is called.
I was jsut doing broad research and sumbled upon this schematic, but cant quite work my head around it.

https://adajusa.fr/en/single-phase-transformers/19929-transformer-63va-e-230-400v-s-115-230v-ip-00-8445340199298.html

What i need to know , if you have 230V derived form 2 phases, and you run that throut the primary coil of a transformer, does that just spit out a 0 / 230V on the other side? if so, does it do that simply by grounding one of them? seems counter intuitive in my inexperienced brain. Soudns like grounding a live conductor to me.

 

[electrofelon]

if so, does it do that simply by grounding one of them? seems counter intuitive in my inexperienced brain. Soudns like grounding a live conductor to me.

A transformer creates a "new" electrical system and you can ground any conductor you want. The conductor you ground on the secondary has no relationship to and does not have to be coordinated with conductors on the primary.

 

[MD Automation]

A transformer creates a "new" electrical system and you can ground any conductor you want. The conductor you ground on the secondary has no relationship to and does not have to be coordinated with conductors on the primary.

Electrofelon beat me to it while I was typing !!



To the OP, not sure of your electrical background, so apologies if you already understand this...

Yes, if you feed 230 VAC to the primary windings of a (1:1 turns ratio) isolation xfmr, you will get 230 VAC on the secondary windings.

And it's important to know that the secondary output is NOT electrically connected to the primary source in any way. The windings are magnetically coupled, that's the magic of the transformer, but no current can ever flow across the secondary to primary windings, or vice-versa. They are "isolated" in that sense, hence the name isolation transformer.

And yes, it might seem counterintuitive to "ground" a "hot" conductor on that secondary, but at the start - and left all to themselves, with neither grounded, that output would be called "floating". Meaning those 2 wires have no reference to anything else, not to ground, nor to anything on the primary. The only measurement that makes sense on the transformer output is from one end of the secondary to the other. You can't measure anything to "ground", because they are still floating.

Think of those 2 secondary wires as points, floating above the ground of an X-Y plane (graph paper if you like). The distance between them is constant, and you can measure that distance from one point to the other (that's the voltage between them), but you can't measure from either point to anything on the ground because the points are floating - they are free to "move" around and will render any measurement to the graph paper meaningless.

So what's commonly done is to take one of those secondary wires and connect it to ground. Now you can call that the "grounded" conductor, it's the circuit conductor that is intentionally grounded.

It's like one of the 2 floating points in my example's XY plane takes a flag and plants it on the ground (call it the 0,0 point on the graph for simplicity). That point says this is where I live now and you can always measure from here, I am no longer floating. Since that point is no longer floating, neither is the other point... it's now referenced to a grounded point.

So it's OK to ground the first conductor from a floating secondary, it won't cause the short circuit you think it might because there was never a path for short circuit current to take before. Everybody was floating. You are simply establishing the first reference to ground.

Now, if you touch the other end of that secondary output to ground... THAT will cause the short circuit you are thinking about. Those 2 points can't try and plant their flag in the same place and still be 230 volts apart. They will try very hard to both live there, and that fight will cause large currents to flow. And in a properly designed circuit, that "fault" current will hopefully trip a circuit breaker or open a fuse.

Again, sorry for all the words if you knew this already.

 

[electrofelon]

I briefly scanned the spec sheet, and even downloaded the install manual, and it does seem ridiculous that they aren't more specific about the input system topology. If indeed the unit must be fed L-N it's a no-brainer to me that they should state that. I would say you should call the manufacturer and find out straight from the horse's mouth if you can run this off 230 volts line line. Maybe there's a setting that can be changed.

 

[pathfinders]

WOW thanks MD, in a single post, you just clarrified about 60 topics i never understood. I never really understood the concept of floating.
A girl in australia was electrocuted in commmunity housing and the media reported it as a floating neutral. till this day, i knew that mean it wasnt grounded but i thought that simply meant it was taking the path of HER to ground instead of the neutral to ground to trip the RCD. I didnt consider that it was because refference was gone..
Electrofelon, yes indeed, thats what i thought. Ive escalated it to the vertiv south east asia team. Ive opened only one of the 6 i bought. im happy to wear that, but im going to politely ask that they consider stopping its distribution in this country, as the countries standard utility in the major cities is 3 phase delta, 230V.
Ive been all through the settings, the only that comes close is a battery ground to neutral setting, which didnt help.

 

[pathfinders]

i did actaully try plugging it in to a 500W servo motor AVR, but no avail. i think that AVR is simply voltage regulation, and doesnt have a ground on the secondary. ill start lookign for affordable well known transformers now.

 

[pathfinders]

so it looks like vertiv have a setting . they responded..


Hi Mr.__

The EDGE is primarily designed to accept a 230V L, N, G input and should still work with L-L. Since you confirmed that your input is 230V L-L, you may enable the following UPS function to prevent it from showing “input phase reversed” alarm which will be irrelevant to your source configuration.

The user / technician may disable the IT system compatibility by following below instruction to hopefully allow the UPS to work properly:


from some other ups manual: IT system compatibility- Enables/Disables the neutral back-feed relay on battery mode.

 

[ruxton.stanislaw]

It is curious to ponder as to why that is related to "IT system compatibility." Regardless, there should always be a "back-feed relay" that breaks the connection to the input plug when the UPS is disconnected from the grid or the grid is offline. I suspect this has something to do with the UPS depending on the neutral-ground bond at the service, for the ground of the UPS load outlets to still function when power is offline.