Axpert invertors

prinslja said:
This is probably the most stupidest question on this thread, but is an "AC Transfer Switch" still necessary when wiring an Inverter between Grid and AC Loads?
:o :erm:
Click to expand...

No, it's not necessary since the Axpert (and many other inverters) automatically transfer the load from the AC to PV / battery as needed.

BUT, you might want to install one, for incase you need to send the inverter in for repairs due to lightning, etc.
 
I have been following the Axpert forum for some time now …. And would like to know the members views on using Solar Frontier 170w high voltage (thin-film technology) solar panels with an Axpert 5kva.

Thanks
dave
 
Valken said:
For all you Axpert/PIP owners out there. You have to give Jaco's software a try at http://aicc.org.za
This is what the software should be and it is stable and gives you all the info that is needed!
Click to expand...

Jaco software only use com port at this stage. Therefore i did write my own to use the usb port to log all the live data and to swich the inverter from utility to Solar Battery mode
 
Hi all,

I have been watching this thread for a long time, reading and learning, cross checking info, and i would like to thank all those that freely shared knowledge from the bottom of my heart.

As a result, I bought an Axpert 5K, a few solar panels, batteries, and a 5.5 KVA Generator, and want to finally install them permanently into the house wiring. Step one will be inverter, batteries and generator to survive the severe 5 day outages we experience where i live. Step two will be to put the panels up, but that will have to wait a bit.

The wiring of panels and batteries i will leave out of the scope of this discussion for the moment.
What this post deals with is the safe wiring of inverter and standby generator permanently into the mains supply, specifically the correct E/L behaviour via neutral earth bonding.

My design, after a hell of a lot of reading, i have posted here:
http://s7.postimg.org/9jgr6kfl7/House_Wiring.jpg

I will update this post and that image as needed to have all details and reasoning described and questions answered, and hopefully it will be useful to someone else. I also have aspirations to get my "going off grid" experience onto a website, but that too will have to wait.

I will be completely replacing the existing DB board, and getting a knowledgeable electrician in to do the COC afterwards.
I do not know such an electrician, so a referral would be great, as i will get him to approve the design before i even start the work.

Let me attempt to talk through the diagram:

I get three phase power to the house delivered to an outside supply box.
These are indicated top left, along with my house's earth spike.
The three live wires go through a breaker, while the neutral does not.

Those cables then run to a box inside the house i have named the Mains/Genset Changeover box.
The three phases run through a prepaid meter, and note that the generator does not or one pays for petrol AND the consumed power. While paying for both is OK in a short term emergency, the idea really upsets me.

Note: I need a mechanism to safely and manually, select between any of the three phases, or the generator if all three phases are not working properly. We have blackouts, brown outs and over voltages all the time, and i have responded in a later post why i need to switch between phases from time to time. I understand the need to balance phases, and there are other houses on our plot that we include in the balancing excercise.

I cannot find 4-input changeover switches in the required current rating, and so have cascaded three regular switches.
I chose the knob type selector switches over the DB board rail mount switches, as those examples of the latter i managed to find are really tough to switch and the wife and kids need to be able to do it easily. I will add lights and voltmeters to the panel so one can easily see the state of the various phases and generator power.

An important note here is that the switches need to be "break-before-make" type, so that you never short phases to each other or the generator.

The first switch is a single throw switch, allowing selection between the first two phases.
Output of that switch runs to a second identical switch along with the third phase.

I now can choose a mains phase between them, and no switch position is ever going to be a problem when phases come on or off.

The output of the second switch is now my mains, much like a house that runs from a single phase, of which i have a Live and Neutral.

These wires are run to a third switch which is a double throw switch. The second input to this switch is the Live and Neutral from the generator itself. This allows safe selection between mains and generator. This switch is wired so that one set of contacts switch between Mains and Generator LIVE, and the second set between Mains and Generator NEUTRAL. This ensures complete separation of upstream wiring.
Side note: The Axpert has a relay that can start a generator when mains power fails or batteries are low. If ever i implement that, this is the switch that will be replaced with the automatic switch. Also, the generator can be started at any time without it being a problem.

FIRST NEUTRAL/GROUND BOND: The generator neutral is bonded to earth BEFORE this switch, so that the bond is isolated when connected to mains, and active when the generator is selected.

Output of this switch, Live and Neutral then is run to the house DB board main switch, along with Earth and Neutral.

I am planning to have a two row DB board, where the first row is used for appliances powered by mains, and the second row dedicated to those that will run off the inverter. Currently, there are three separate neutral bus bars, and this was done to incorporate what i learned on this thread. It is open to criticism; this is why i posted. :)

First row has the mains breaker, which breaks both live and neutral.
Neutral goes to its own busbar.
Live goes to the first breaker that feeds the Axpert Mains IN, feeding the inverter "clean power".

Live also goes to Mains Row E/L, which in turn has its own neutral bus bar, not connected to the first.
After the E\L, live is fed to a couple of breakers that run those appliances that i cannot afford to run off batteries, and i can add more as needed. These appliances are E\L protected.

The Axpert Mains OUT is then fed to its own E/L in the second row of the DB.
This E\L outputs to a third, dedicated neutral bus bar.

SECOND NEUTRAL/GROUND BOND: Note that the Inverter Output Neutral is bonded to earth BEFORE the E/L.
From what i have read, this bond SHOULD NOT exist when the inverter is relaying mains on bypass mode.

From reading it seems the manufacturer has a relay in the case that bonds neutral to earth when supplying from the inverter, and breaks the bond when in bypass mode. I am nervous to make this assumption, and i need to figure out a way to test this. If this feature doesn’t exist, an automatic contactor is required to make or break this bond based on whether there is power on the top row Mains Switch.

After that, it is straight forward, the second E/L feeds a row of breakers.

Your thoughts, ladies and gentlemen, are welcome, and much appreciated.
 
Last edited:
OK, I've read your post and looked at your diagram. Most of it seems fine except the following:
The idea of a 3 phase connection is to have an equal (or close to equal) load per phase - what you are trying to do here is to use one of the 3 phases at any given time, without any load on the other two phases - if that is how you and your neighbours operate that is maybe why you are experiencing brownouts all the time. I'm not at all familiar with the 3 phase kWh meters and don't know how they will register the usage if you only utilise 1 phase at a time, but you might want to get an expert opinion about that as well. Bottom line, using 1 of the 3 phases at a time is not at a good idea.

Then the bonding relay thing - the Axpert does not have a bonding relay in place, if you want a bonding relay, you will have to open the Axpert and tap the power for the bonding relay from the "safety relay" in the Axpert, if memory serves well.

My 2c
 
superdiy said:
The idea of a 3 phase connection is to have an equal (or close to equal) load per phase - what you are trying to do here is to use one of the 3 phases at any given time, without any load on the other two phases - if that is how you and your neighbours operate that is maybe why you are experiencing brownouts all the time. I'm not at all familiar with the 3 phase kWh meters and don't know how they will register the usage if you only utilise 1 phase at a time, but you might want to get an expert opinion about that as well. Bottom line, using 1 of the 3 phases at a time is not at a good idea.
Click to expand...

Hi SuperDIY,

Thank you for the response, i will check out the internal relay option you describe, i think do have a service manual somewhere i downloaded from a local agent.

The three phase meter we use works fine when only on or two phases as far as i can measure, but it is a good idea to contact the vendor and make sure. We have a mix of single and threephase meters for the various units, provided by a non Eskom private vendor. Will revert with findings for posterity.

As for balancing the phases, i didn’t want to include this story in the main post. We have many units on our smallholding, and i go out of my way to spread the load between the phases as evenly as possible as tenants and seasons come and go, and to be as easy as we can on the transformer. The real reason for it is that we live across the road from a huge informal settlement, and there are at least 30 guys stealing power and reselling it without regard for safe wiring, not a breaker in sight, cables on fire, and transformers boiling and exploding every 4 to 8 weeks. Any balancing attempts on our side of the road are totally lost and mostly pointless.

We have lost 10 transformers in the last year. And Eskom is VERY slow in approving our application to have it moved to inside our perimeter. They don’t care much, as the replacement is insurance funded, and they take their time. They are also very hesitant to work on our transformer at all, as the guys got shot at once, and now wait to book a police escort to fix anything that goes wrong, and then only in daylight hours.

Needless to say, all of us are making a mission to vastly reduce our dependency on Eskom.
 
Last edited:
Sjees man, now I understand your dilemma. Well, in that case, I guess the phases will be completely unbalanced as is and your connection to 1 phase at a time would probably not cause more harm, but maybe less, depending on the other illegal connections at that point in time. :)

I want to wish you the best of luck with your project!
 
One of my customers just had some electronics blow up . The neutral on the transformer got loose. Some of thier pcs was zapped with 380v :(
Now the question will the axpert survive such a surge and protect devices connected via it ?
 
Possibly the Axpert is not on-line but the internal change over relay could open quick enough to prevent over voltage damage
 
thehuman said:
One of my customers just had some electronics blow up . The neutral on the transformer got loose. Some of thier pcs was zapped with 380v :(
Now the question will the axpert survive such a surge and protect devices connected via it ?
Click to expand...

This is why you should ideally use a UPS on every PC, even if there is an inverter in the building.
 
thehuman said:
One of my customers just had some electronics blow up . The neutral on the transformer got loose. Some of thier pcs was zapped with 380v :(
Now the question will the axpert survive such a surge and protect devices connected via it ?
Click to expand...

It may.
To survive that your device needs to switch over on high voltage and needs some MOVs to protect for the short period before switch over.

IIRC the Axpert does have MOVs but you can buy them pretty cheaply anyway.

Ideally your load should be isolated with a transformer and switch over, like line interactive UPS to provide protection against that.

The Axpert lacks the transformer when in AC mode.
 
Most of what you have, looks OK from the face of it (I presume this is why I got the PM from you too)... However,

MaSahara said:
Hi all,
My design, after a hell of a lot of reading, i have posted here:
http://s7.postimg.org/9jgr6kfl7/House_Wiring.jpg
...

Note: I need a mechanism to safely and manually, select between any of the three phases, or the generator if all three phases are not working properly. We have blackouts, brown outs and over voltages all the time, and i have responded in a later post why i need to switch between phases from time to time. I understand the need to balance phases, and there are other houses on our plot that we include in the balancing excercise.

I cannot find 4-input changeover switches in the required current rating, and so have cascaded three regular switches.
I chose the knob type selector switches over the DB board rail mount switches, as those examples of the latter i managed to find are really tough to switch and the wife and kids need to be able to do it easily. I will add lights and voltmeters to the panel so one can easily see the state of the various phases and generator power.
Click to expand...

That - is *dangerous*. You will have serious back feeds when switching live running loads from one phase to the other, and due to the phases being out of sync (P1, P2, & P3), you could potentially damage equipment as well when switching the phases if they are under load.

I would recommend you use one phase for normal power (with generator backup), and one phase for PV power (with inverter & PV) and then discard the third phase completely (Eskom won't like you, but it's not against the rules).

Then use a normal change over switch to switch only the inverter between your "normal" phase, and your "PV power" phase in the case that one or more of your phases fail. Your "normal" phase will have backup from the generator, and your "PV Power" will have backup from the PV and/or Change over switch, depending on how the switches are thrown.

Remember when you talk generator and inverter, you need to switch your live *and* neutral, in all instances.
 
bb61bb57c903eee8b0f2ed9e22798fbe.jpg

will fit over weekend
 
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