Understanding Surge Protector Specs for the Computer Age

[kiki_danc]

Here is the link I also shared in the same message https://zerosurge.com/normal-mode-v-common-mode/
After discussing with the electrician.. here are the complete facts.

The building service entrance is 3 phase with delta transformer... per phase is 120 volts.. but we never have any 120 volts outlets because 100% of our equipments are all 220 volts.. therefore my 220 volts in the outlets came from the line 1 and line 2 (or line 2 and 3 or 1 and 3) of the 3 phase.. in another floor.. the breaker is 3 phase. The one in the picture is admin breaker supplying only lights, cctv and security, hence only single phase needed and the design just tapped the phase 1 and 2 of the 3 phase service entrance power. With all these information.. my Spd type 2 that is line to ground won't be engaged at all because I don't have any equipments in the outlets that is 110 volts, right? If you agree, then I'll remove the existing SPDs and return them to supplier and buy a line to line SPD or delta SPD instead. Thanks.

Here's the breakers in my service entrance:

The front silver thing is the ground lugs. We don't have any neutral. If you will measure the voltage in any of the lines to the ground or even the enclosure, it's 120 volts.. but we never use 120 volts because all our equipments are 240 volts.. the one in the middle is the admin which connects to the panel you saw earlier. Therefore what I need are line to line SPD protecting 2 phases and not 1 phase to ground which is not utilized, right?? In the event there is surge in the line to line (phase 1 to phase 2), would it separately shunt to ground without any equipments actually connected to any phase and ground (or 110 volts we never used?)

 

[Tom.G]

OK, your last post added much missing information and cleared up much confusion. (Whew!)

I see two relatively easy approaches:

1. Use a Control Transformer to feed the power supply, 240V primary, 120V secondary
2. If it is legal with your particular wiring where you are, tap 120V from one leg and use the common Ground as Neutral.

Either way, you can then use a 120V SPD at the power supply. This addresses your concern about the 300V input limit of the power supply.

With option 1., if you use an appropriately sized (small enough) Control Transformer you can use a type 3 SPD and you do not need the 10m wire length before the SPD, the transformer impedance will be more than adequate. You will still need a Ground connection wire for the SPD (or use the conduit if it's legal there). That's because high voltage spikes can get thru a transformer due to the capacitance between primary and secondary.

If you use option 2. above, you will need a type 2 SPD.

You could ask your power company or the city electrical inspector about the legality of option 2.

Cheers,
Tom

p.s. Please let us know how this all works out. Many people here have put time and effort into this and we are always curious.

 

[kiki_danc]

OK, your last post added much missing information and cleared up much confusion. (Whew!)

I see two relatively easy approaches:

1. Use a Control Transformer to feed the power supply, 240V primary, 120V secondary
2. If it is legal with your particular wiring where you are, tap 120V from one leg and use the common Ground as Neutral.

Either way, you can then use a 120V SPD at the power supply. This addresses your concern about the 300V input limit of the power supply.

With option 1., if you use an appropriately sized (small enough) Control Transformer you can use a type 3 SPD and you do not need the 10m wire length before the SPD, the transformer impedance will be more than adequate. You will still need a Ground connection wire for the SPD (or use the conduit if it's legal there). That's because high voltage spikes can get thru a transformer due to the capacitance between primary and secondary.

If you use option 2. above, you will need a type 2 SPD.

You could ask your power company or the city electrical inspector about the legality of option 2.

Cheers,
Tom

p.s. Please let us know how this all works out. Many people here have put time and effort into this and we are always curious.

In your post. You were assuming we have 120 volts equipments or power supplies. We never have this. If we order items from the US which uses 120 volts. We always use up-transformer to convert the 120 volts to 240 volts because all our gadgets and stuff uses 240 volts.. therefore what would be the use of 120 volts.

But I realized you were right that in my current installation, the 320 Vac SPD is too much for the 120 volts phase to ground that we never use or a mismatched.

Supposed I don't want to use any 120 volts which we don't use. And reviewing the delta configuration:

If I'll use the ac power configuration as originally given.. that is using phase A and B to power the computer producing 240 volts. And there is a surge, would the SPD installed in phase A to ground suppress the wires connecting phase A and B? I just want a definite yes or no. If no, then I'll look for a line to line MOV and SPD and either return the installed SPD or sell it since it doesn't do its intended function at all. Thanks so much.

 

[Tom.G]

would the SPD installed in phase A to ground suppress the wires connecting phase A and B? I just want a definite yes or no.

No.
The power supply you specified in post #1

I have a power supply model Mean Well RS-50-24

is universal input voltage capable over the input range of 88V to 264V so it will work with 120V input.

 

[kiki_danc]

No.

Thanks for this. I'll try to get a Line to Line SPD instead. But 3 phase SPD is very expensive at more than $1000.

The power supply you specified in post #1

is universal input voltage capable over the input range of 88V to 264V so it will work with 120V input.

Oh.. the meanwell power suppy. I finally understood what you were saying or implying in your last message. But if I tap the 120 volts and the ground.. won't the ground attract unwanted and unpredictable voltage sfrom either surges from other buildings or lightning strikes or etc (since ground is connected to all the enclosures and power dirt source in the entire city). I wonder if this is advisible even if city hall would permit it.

Lastly. I found out I can no longer return the 320Vac type 2 SPD. If I'd use this for the above idea of using 120 volts from line to ground.. I wonder if there is some adverse behavior from using SPD of much higher voltage rating (320 Vac) for power source that is much lower (120 volts)? I can't find any answer of this online because no many are foolish to use much higher SPD voltage rating but I'm stuck with it so asking this.

Thank you so much for your thoughts and advices.. 5 stars to you.. i'd "like" every post of yours lol...

 

[Tom.G]

I wonder if there is some adverse behavior from using SPD of much higher voltage rating (320 Vac) for power source that is much lower (120 volts)?

The 'adverse behavior' is the higher clamping voltage, which you cited as a problem earlier.

Thank you so much for your thoughts and advices.. 5 stars to you.. i'd "like" every post of yours lol...

A few of the the better ones in this thread would be adequate.

 

[kiki_danc]

The 'adverse behavior' is the higher clamping voltage, which you cited as a problem earlier.

A few of the the better ones in this thread would be adequate.

I got all useful information now to make sure the supplier would refund the SPD to be removed (to be replaced with a line to line spd).. if he won't refund and he is the supplier of it direct from Prosurge in china.. then I'd give technical details to the china head that the supplier doesn't first check my power system before installing it so my supplier would indeed refund it.

Thanks to you again and to Rive (and others who helped).

 

[kiki_danc]

Update. I am debating with the Prosurge supplier. He kept telling me he installed TVSS for a decade and sure an SPD intended for line to ground can work if the load is line to line... again consider the illustration:

If my computer is connected to Phase A and Phase B and the SPD is intended for Phase A and Ground.. why wouldn't it work? There is a potential for the phase and ground.. so won't the SPD be engaged even if the load is not connected to ground. Case in point.. if you touch the phase to ground, the connection would explode.. so there is great potential between the phase and ground.. so if an SPD is installed between phase and ground.. won't it be activated even if the surge occurs at Phase A and B? Please give arguments what is the case at hand just so in case the supplier could be right in some ways. Thanks (this is the last question! promised.. lol)

 

[kiki_danc]

Update. I am debating with the Prosurge supplier. He kept telling me he installed TVSS for a decade and sure an SPD intended for line to ground can work if the load is line to line... again consider the illustration:

View attachment 231338

If my computer is connected to Phase A and Phase B and the SPD is intended for Phase A and Ground.. why wouldn't it work?

To clarify. I mean if there are two SPDs intended for phase A to ground and phase B to ground.. won't they shunt a phase A and B load and eliminate the surge between phase A and B?? I omitted the phase B to ground in my last question which you answered "No".

There is a potential for the phase and ground.. so won't the SPD be engaged even if the load is not connected to ground. Case in point.. if you touch the phase to ground, the connection would explode.. so there is great potential between the phase and ground.. so if an SPD is installed between phase and ground.. won't it be activated even if the surge occurs at Phase A and B? Please give arguments what is the case at hand just so in case the supplier could be right in some ways. Thanks (this is the last question! promised.. lol)

 

[kiki_danc]

To clarify. I mean if there are two SPDs intended for phase A to ground and phase B to ground.. won't they shunt a phase A and B load and eliminate the surge between phase A and B?? I omitted the phase B to ground in my last question which you answered "No".

I think it can work in the sense of the line to line protection mode being protected by the series combination of the line-to-ground and ground-to-line modes. But why haven't you considered this? And what would be the behavior of this series mode. I only know the MCOV voltage would add up becoming 320V+320V=640 V (and clamping voltage would further increase). But would the two SPDs in series to the line to line become heating elements (to suppress the surge) or would they still shunt the voltages to the ground? I think this might be what the supplier was trying to consider. He couldn't explain the details. And I can't find the reference about this in google. So hope to get your opinion of the scenerio. Thanks again.

 

[Tom.G]

the MCOV voltage would add up becoming 320V+320V=640 V (and clamping voltage would further increase).

Yes, that would be the case; you could get twice the expected voltage line-to-line if the SPDs were rated at the line-to-line voltage and were connected line-to-ground. Also, your earlier posts seemed to indicate that the 240V 3-phase was not referenced to ground (which I found rather strange at the time and was cleared up in your post #61.) Since in reality you have 120V 2-phase, 120V SPD on each line would work. There are also 120v/240v SPDs for exactly that situation. But that would exceed the 300V limitation on the power supply input voltage. The only way to address the 300V limitation is to supply 120V to the power supply.

But why haven't you considered this?

Because that was not the question you asked. You asked in post #63 "computer is connected to Phase A and Phase B and the SPD is intended for Phase A and Ground."

As a side comment, I am not at all surprised that your attempt to return the already installed SPDs was rejected. The vendor has no way of knowing or testing if the have been damaged by a surge. Would you willingly buy a used protective device at full price knowing that it is in unknown condition? At least here in the USA, electrical and electronic components that have been installed are not returnable, for not only that reason but the vendor could be liable for any subsequent damage.

Cheers,
Tom

 

[kiki_danc]

Yes, that would be the case; you could get twice the expected voltage line-to-line if the SPDs were rated at the line-to-line voltage and were connected line-to-ground. Also, your earlier posts seemed to indicate that the 240V 3-phase was not referenced to ground (which I found rather strange at the time and was cleared up in your post #61.) Since in reality you have 120V 2-phase, 120V SPD on each line would work. There are also 120v/240v SPDs for exactly that situation. But that would exceed the 300V limitation on the power supply input voltage. The only way to address the 300V limitation is to supply 120V to the power supply.

Because that was not the question you asked. You asked in post #63 "computer is connected to Phase A and Phase B and the SPD is intended for Phase A and Ground."

As a side comment, I am not at all surprised that your attempt to return the already installed SPDs was rejected. The vendor has no way of knowing or testing if the have been damaged by a surge. Would you willingly buy a used protective device at full price knowing that it is in unknown condition? At least here in the USA, electrical and electronic components that have been installed are not returnable, for not only that reason but the vendor could be liable for any subsequent damage.

Cheers,
Tom

Oh I haven't thought of it that supplier won't accept the product for return because it may suffer a bit of surge damage already.

Anyway you haven't answered this question:

So the above will work only at increased clamping voltage. Ok. But I was asking if the surge would be dissipated by the current going to the ground or the MOV element just heating up... what do you think?

 

[kiki_danc]

Here's an interesting experiment in the paper at http://www.surgesuppression.com/ima...licationofSurgeSuppressionRevDate10202005.pdf

Power was applied to Phase A and B and thermometer was used to measure the temperature of the MOV when surge was introduced (details in the paper above).

Based on the much higher temperature rise in the discrete line-to-line MOV, the discrete line-to-line MOV absorbs a much larger portion of the surge current and energy than the combination of the two line-to-neutral paths.

In the experiment, why did the MOVs heat up in the 2 element Phase A to ground & Phase B to ground MOVs (instead of just the 1 discrete line to line MOV).. is the current of the 2 element series not shunted to neutral? I assume neutral is same as ground.

If the neutral were made ground.. would the results be the same?

And lastly if there was no discrete line to line MOV used.. what would be the behavior of the 2 elements MOV in series (the Phase A to ground and Phase B to ground MOV).. would it behave less than discrete line to line or similar in shunting the current? What do you think?

Knowing the answers above would wrap up my questions about SPD and end up this thread once and for all. Lol.

 

[kiki_danc]

Here's an interesting experiment in the paper at http://www.surgesuppression.com/images/DotNetSite/TechPapers/ModesofProtectionwithinElectricalSystemsforApplicationofSurgeSuppressionRevDate10202005.pdf

View attachment 231382

View attachment 231383Power was applied to Phase A and B and thermometer was used to measure the temperature of the MOV when surge was introduced (details in the paper above).

Based on the much higher temperature rise in the discrete line-to-line MOV, the discrete line-to-line MOV absorbs a much larger portion of the surge current and energy than the combination of the two line-to-neutral paths.

In the experiment, why did the MOVs heat up in the 2 element Phase A to ground & Phase B to ground MOVs (instead of just the 1 discrete line to line MOV).. is the current of the 2 element series not shunted to neutral? I assume neutral is same as ground.

If the neutral were made ground.. would the results be the same?

And lastly if there was no discrete line to line MOV used.. what would be the behavior of the 2 elements MOV in series (the Phase A to ground and Phase B to ground MOV).. would it behave less than discrete line to line or similar in shunting the current? What do you think?

Knowing the answers above would wrap up my questions about SPD and end up this thread once and for all. Lol.

Since MOV can be used between line to line as indicated in the paper above.. I wonder what would happen in the following if one of my 320 Vac MCOVs (instead of two) were put between the 120 volts line:

Of course I won't try it (I'm not crazy to experiment). Just want to know what theoretically would happen.. would it explode? Or work in a while then shuts down? etc.

 

[Tom.G]

This is in response to your post #72. I must have forgotten to click the POST REPLY button before I went off-line for a while.

Another case of insufficient information or under specified condition. You show a 3-phase transformer without a Ground or Common connection, in an earlier post you specified 3-phase 240V with 120V to a Common. Here the 3 lines are labeled 120Vac but your earlier posts stated the transformer windings as 240V. When measuring 120Vac on this diagram where is the other voltmeter lead placed?

 

[kiki_danc]

The other voltmeter lead is placed in the ground lugs of the panel which is simply connected to the Earth or soil. Our power company doesn't have separate ground or neutral. My service entrance has only 3 wires (3 phase) coming to the building.. we provide our own ground by sticking it to earth. I'm sure of this because I inquired from the power company years ago.

Anyway, the 120 volt thing has opened the floodgates in that I can now access all of amazon products which are based on 120 volts. Before I had difficulty finding supplier.. and only found one prosurge distributor locally. Now I can buy for example $69 Prosurge at amazon like https://www.amazon.com/dp/B012IR9Q2K/?tag=pfamazon01-20

My supplier sold the 240 volts version at more than $100. At amazon the 120 volts same specs is only $69. Now I am curious about something. In the United States.. you have Line to Neutral of 120 volts.. and you use it to power your appliances.. if you have 3 phase there.. is it also 120 volts per phase.. meaning if you connect phase to phase.. then it's also 240 volts? I wonder if the US and my place has same power transformers and only the tapping differs. And does it matter if the ground is provided in the transformer or in the soil. Our power company simply doing cutting costs by saving the ground in the transformer and we need to provide ourselves.

I'm asking you this since you can describe it from the perspective of what I mentioned in this thread. Also I think I'd better get a line to line SPD. I saw this at amazon. https://www.amazon.com/dp/B0052NKYC4/?tag=pfamazon01-20
Siemens TPS3A03050 120/240 Type 1 Split Phase Surge Protective Device Lightning Arrester Replacement

In the US. Is there a 120/240 split phase power system? Is it the same as the Delta with 120 volts per phase in my place (and 240 volts line to line)?

I promise this is the last level of inquiry as I don't want to get so much of your time. And as a way of saying thanks.. I can give you my 240 volts prosurge if you need it.. lol
​

 

[Tom.G]

Reference your post #73.

In the experiment, why did the MOVs heat up in the 2 element Phase A to ground & Phase B to ground

Remember that the MOV's act like a resistor when they conduct, their voltages rise as their current increases. The 300V sum of the 2 MOV voltages is close to the 320V of the line-to-line MOV. With the voltages being so close they are sharing the current.

is the current of the 2 element series not shunted to neutral?

The current DIFFERENCE between the 2 elements would typically be shunted to Neutral (which is usually Ground). For instance if one of the MOV's conducted 100A and the other 120A, then 20A would typically flow thru the Neutral lead. There is not enough detail of the test setup nor is it known to me if your Neutral/Common is indeed connected to Ground, and if so what the current capability is of that connection.

If the neutral were made ground.. would the results be the same?

Similiar, see previous comment.

if there was no discrete line to line MOV used.. what would be the behavior of the 2 elements MOV in series (the Phase A to ground and Phase B to ground MOV).. would it behave less than discrete line to line or similar in shunting the current? What do you think?

Similiar... but then you have the situation of when one fails you have no protection on that line.

Cheers,
Tom

 

[Tom.G]

EDITS in Blue[/color]. (Must remember, not after midnite!)

In the United States.. you have Line to Neutral of 120 volts.. and you use it to power your appliances.. if you have 3 phase there.. is it also 120 volts per phase.. meaning if you connect phase to phase.. then it's also 240 volts?

For single family and most multi-family residential the service 120/240V split phase; that is the transformer secondary on the power pole is 240V center-tapped, with the center tap (CT) conneced to Earth at the transformer and also brought to the building with the two 120V wires, where the CT is called Neutral. This Neutral is also grounded at the circuit breaker box with a large wire connected to a long metal rod driven into the Earth. Large appliances, such as an electric stove, are connected to all three wires, making both 120V and 240V available.

In the US. Is there a 120/240 split phase power system? Is it the same as the Delta with 120 volts per phase in my place (and 240 volts line to line)?

Yes, it is available. It is usually used for larger buildings as a way to balance the load across the 3 phases that the power company supplies. At the point of use it is treated as 3 separate supplies, sometimes with a separate electric meter for each.

There is also 120/277V 120/208V 3 phase available for larger multi-family residential and medium industrial. These transformers have 120V secondaries connected in the Wye (or Star) configuration, making a 4 wire supply. The common point (Neutral) of the three secondaries is connected to Earth, brought to the building, and Earthed at the breaker box. 120V is available from any phase to Neutral, and 277V 208V is across any two phases. The 120V is used for the usual wall outlets, etc. The lighting is often 277V single phase fluorescent fixtures, and the 277V 208V 3 phase is for large motors, etc.

Larger industrial typically is supplied with 480V 3 phase, but I don't now the details of that configuration. either Delta or Wye connected. The Wye connected supplies 277V phase to Neutral and 480V across phases. The lighting is often 277V single phase fluorescent fixtures. There would be an on-site transformer to supply 120/240V split phase for wall outlets, etc. (Must have a coffee maker, you understand!)

Thanks for the Prosurge offer, but I have a 120/277V 120/208V service here so it wouldn't be a good fit. Keep it around you may have a use for it, (maybe even next month. who knows!)

Cheers,
Tom

p.s. What is that 24VDC power supply supplying power to?
p.p.s The breaker box photo with the 3 phase breakers must be connected to three split phase transformers somehow.

 

[kiki_danc]

p.s. What is that 24VDC power supply supplying power to?
p.p.s The breaker box photo with the 3 phase breakers must be connected to three split phase transformers somehow.

The 24v dc is connected to a very sophisticated security system with cctc, motion detectors, fire panels, gsm dialers etc

Yes the 3 breakers are connected to each of the 3 phase wire entering the buildings.

So if i buy the siemens 120/240 split phase spd with discrete line to line protection. It should be compatible to my delta 3 phase with 120v each phase?

Reference your post #73.
View attachment 231389Remember that the MOV's act like a resistor when they conduct, their voltages rise as their current increases. The 300V sum of the 2 MOV voltages is close to the 320V of the line-to-line MOV. With the voltages being so close they are sharing the current.The current DIFFERENCE between the 2 elements would typically be shunted to Neutral (which is usually Ground). For instance if one of the MOV's conducted 100A and the other 120A, then 20A would typically flow thru the Neutral lead. There is not enough detail of the test setup nor is it known to me if your Neutral/Common is indeed connected to Ground, and if so what the current capability is of that connection.

In normal power system like in US single phase supply.. when the SPD short circuits to ground.. I thought all the current would go to ground.. isn't it this is the purpose of SPD being connected to ground... where all current would go. In the above experiment, let's say the neutral is connected to ground and have enough wire size.. isn't it the 100A conducted in one would go to the ground? Why did you say only 20A goes to the ground? Also the 2 phase is 120 degree out of phase like in the following:

so when one is conducting.. the other may not.. or you mean they conduct at same time? But why the 20A difference?

Similiar, see previous comment.Similiar... but then you have the situation of when one fails you have no protection on that line.

Cheers,
Tom

The experiment seems to be saying that discrete line to line SPD protection is more effective.. why do you say it's the same? The paper comments on the paragraph about it that:

"In contrast, if an SPD with only seven modes of protection is utilized for the same system and the line-to-line protection mode is proteced by the series combination of the line-to-neutral and neutral-to-line modes or the line-to-ground and ground-to-line modes, then those modes (line-to-neutral or line-to-ground) are intentionally exposed to unnecessary and undesired transient voltages. In essence, the SPD is sharing the line-to-line transient with the line-to-neutral and line-to-ground modes and creating voltages on those modes that would not be present with the use of a discrete all mode protection SPD."

​

What would happen if the ground to neutral is intentionally exposed to unnecessary and undesired transient voltages?

For general line to line protection.. do they use dedicated line to line SPD (without ground but heating the element) or do they use line-to-ground and ground-to-line like in my setup? I want to know if my existing setup is common or not.

 

[Tom.G]

See corrections to my post #78 https://www.physicsforums.com/threads/surge-protector-specs.955697/page-4#post-6064607

(Amazing the things you think of while falling asleep.)

 

[kiki_danc]

Tom. Thanks to you the supplier and distributor have decided to send me a 150Vac SPD for free (after they realized we are right the clamping voltage can increase).. but then I'm having second thought.. I plan to get the Siemens 120/240V split phase at amazon with protection mode that includes L-L. As detailed in my last message, Protection mode that include L-L is more superior than the series connections of two spds, right?

And before I order. I'm verifying if my transformers are really Delta or Wye. Looking at file photos. I found out there was a neutral or ground entering the busbar (white wire among the 3 big black).

This is my actual transformers (some details faded for security).

The two transformers tap to only 2 high tension wires above it, the 3 phase wire entering my service entrance is from the A, B and C terminals. The right transformers has label "x1", "x2", and "x3". So it comes from "x1" and "x3" while on the other side, the terminal C is from "x1".

Do you recognize the transformers as Wye or Delta?

And if I order the Siemens 120/240v split phase at amazon.. it should be compatible by only tapping to the 2 phase of the 3 right? (since I'd just use the admin breaker for the surge protectors and not the full 3 phase breakers).

https://www.amazon.com/Siemens-TPS3A03050-Protective-Lightning-Replacement/dp/B0052NKYC4/ref=sr_1_1?ie=UTF8&qid=1538355017&sr=8-1&keywords=siemens+120/240v+split+phase

Hope to order it soon and done with all this so we can focus back on string theory... lol.. my electrician will install the Siemens don't worry. Thank you.

 

[Tom.G]

Protection mode that include L-L is more superior than the series connections of two spds, right?

Right.

The two transformers tap to only 2 high tension wires above it

With only 2 high tension wires and 2 transformers I fail to see how there can be 3 phases. At a minimum you need a wire and transformer for each phase. Can you supply a sketch of the the wiring for both the primary and secondary of the transformers? For instance there has to be at least 2 terminals wired for both the primary and secondary of each transformer.

I found out there was a neutral or ground entering the busbar (white wire among the 3 big black).

Yes, it looks like the busbar box in the photo already has 120V going thru it. That's the Blk, Wht, Grn trio in the lower right. Wht = Neutral, Blk = Hot, Grn = Earth Ground. Why are you resisting using the existing 120V for the 24VDC power supply? Or even a control transformer to step the 240V down to 120V? After all, the time spent so far already exceeds the cost of a control transformer by a big margin.

 

[kiki_danc]

Right.

With only 2 high tension wires and 2 transformers I fail to see how there can be 3 phases. At a minimum you need a wire and transformer for each phase. Can you supply a sketch of the the wiring for both the primary and secondary of the transformers? For instance there has to be at least 2 terminals wired for both the primary and secondary of each transformer.

Yes, it looks like the busbar box in the photo already has 120V going thru it. That's the Blk, Wht, Grn trio in the lower right. Wht = Neutral, Blk = Hot, Grn = Earth Ground. Why are you resisting using the existing 120V for the 24VDC power supply? Or even a control transformer to step the 240V down to 120V? After all, the time spent so far already exceeds the cost of a control transformer by a big margin.

No. The Green black, white wires in the lower right are connected to another breakers below. I bought green wires 5 years ago because there was no other colors on stock. During installation, the electrician said green is for Earth ground but I already bought 30 meters and it's already cut. So they are not separate power from outside.. but just half meter wires to be connected to a meter below it and breaker and to another room.

Well. In my place all most use line to line of 240 volts. It's rare to use 120 volts. So our neutral or ground is virgin. If I connect the line to ground (of course after asking permission from city hall). And in other floors my hands touch the ground, won't I be jolted by electricity?

My solution is to add a type 3 to the equipments so the 1200 volts or so VPR in the type 1 or 2 would be lowered to 220 volts. This is better solution because remember I have 6 meters wire connecting from type 1 or 2 to equipments.. those can increase the voltage beyond 300 volts..

I'll find the explanation of how they can make 3 phase from 2 wires from high tension wires and 2 transformers and post it later.

 

[kiki_danc]

No. The Green black, white wires in the lower right are connected to another breakers below. I bought green wires 5 years ago because there was no other colors on stock. During installation, the electrician said green is for Earth ground but I already bought 30 meters and it's already cut. So they are not separate power from outside.. but just half meter wires to be connected to a meter below it and breaker and to another room.

Well. In my place all most use line to line of 240 volts. It's rare to use 120 volts. So our neutral or ground is virgin. If I connect the line to ground (of course after asking permission from city hall). And in other floors my hands touch the ground, won't I be jolted by electricity?

My solution is to add a type 3 to the equipments so the 1200 volts or so VPR in the type 1 or 2 would be lowered to 220 volts. This is better solution because remember I have 6 meters wire connecting from type 1 or 2 to equipments.. those can increase the voltage beyond 300 volts..

I'll find the explanation of how they can make 3 phase from 2 wires from high tension wires and 2 transformers and post it later.

I'm sure it's 3 phase from 2 transformers. I used binocular to look at the wires. The wires are tangled so I can't tell the details. But the following is one explanation of how to get 3 phase from 2 transformers.

http://forums.mikeholt.com/showthread.php?t=144067 (better source.. )

https://www.diy-forums.com/threads/three-phase-from-2-transformers.279495/

 

[kiki_danc]

I'm sure it's 3 phase from 2 transformers. I used binocular to look at the wires. The wires are tangled so I can't tell the details. But the following is one explanation of how to get 3 phase from 2 transformers. https://www.diy-forums.com/threads/three-phase-from-2-transformers.279495/

If you will google "3 phase from 2 transformers".. many explanations would come out.. for example:

http://forums.mikeholt.com/showthread.php?t=144067

best explanation in the following from above.. "It's called "open delta". If you Google this term, you will get all kinds of info.

"Picture three transformers providing 240/120V 3� 4W service that you mention. Now remove one not center-tapped. The voltage and phase across the terminals where the removed transformer was formerly connected is still the same.

BTW, POCO's still do this. "

here it says "open delta".. so I guess it answered what kind of transformers I have.. an open delta.. btw.. are you an electrical engineer?

 

[Tom.G]

Yes, I looked at the link you first posted and the links in it. They are all talking about using 2 transformers fed from a 3 phase generator and 3 phase distribution system. That's 3 phases with a 120° phase shift between them on three wires. You stated there are 2 wires in the high tension distribution side, not 3. Even the wikipedia diagram about half way down the page shows a 3 phase supply. How can you receive three different phases on 2 wires? There is only on way to connect a meter or transformer to them

 

[kiki_danc]

Yes, I looked at the link you first posted and the links in it. They are all talking about using 2 transformers fed from a 3 phase generator and 3 phase distribution system. That's 3 phases with a 120° phase shift between them on three wires. You stated there are 2 wires in the high tension distribution side, not 3. Even the wikipedia diagram about half way down the page shows a 3 phase supply. How can you receive three different phases on 2 wires? There is only on way to connect a meter or transformer to them

There are 3 high tension wires above it.. but there is only one terminal per transformer.. I can't see where the third one taps to... where should it be theoretically? Maybe you can find the third wire?

 

[kiki_danc]

There are 3 high tension wires above it.. but there is only one terminal per transformer.. I can't see where the third one taps to... where should it be theoretically? Maybe you can find the third wire?

View attachment 231459

I think I found the third wire.. it's tapped to small terminal (shown in red lines) at left transformer (connecting to the front most high tension wire)… the 2nd is hidden.. the rear high tension wire is connected to the terminal at right transformer

Whatever. It's an Open Delta Transformer.. so the Siemens 120/240V split phase is compatible by connecting to the 2 phases of 3? If yes. I'll order at amazon now and be done with all of this :)

 

[kiki_danc]

I think I found the third wire.. it's tapped to small terminal (shown in red lines) at left transformer (connecting to the front most high tension wire)… the 2nd is hidden.. the rear high tension wire is connected to the terminal at right transformer

View attachment 231460

Whatever. It's an Open Delta Transformer.. so the Siemens 120/240V split phase is compatible by connecting to the 2 phases of 3? If yes. I'll order at amazon now and be done with all of this :)

reviewing my electrical plans.. my wires in admin breaker is 8mm^2 and ground is just 3.5mm^2 to main circuit breaker... so I can't use line to ground because the ground wire size is made smaller because we always use line to line in my place. Anyway in the US.. when you connect line to neutral and get 120 volts.. and you touch the neutral wires in other places in the building or room. won't you get electrocuted? So I'm thinking if I really connect line to ground.. and touch other ground wires.. I may get electrical shock? no?

Whatever, the siemens 120/240V split phase is good to go.. isn't it.. when it's written protection mode includes L-L.. I assume it uses discrete MOV that heats up instead of moving the current to ground.. (?)

 

[Tom.G]

Yes, the Red looks to be the long-lost third wire. And the diagram in post #85 is similar to what I suspected when you said only 2 wires, I just wasn't familiar with the Open Delta configuration. (I learned something new. GREAT!)

But I still don't comprehend why you won't supply 120V thru a transformer to the 24VDC supply. The 240V SPDs won't keep the spikes below the 300V input rating of the supply. That was a limitation you stated earlier in the thread. Can you explain?

Cheers,
Tom