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Karl avatar image

MultiPlus 24/3000/70-50 Inverter Configuration Type

What type of inverter configuration is incorporated in the MultiPlus 24/3000/70-50?
Does it incorporate an isolating transformer?

or is it transformerless?

If it incorporates a transformer can you please let me know the impedance of the load side winding?

I am attempting to calculate the external part of the fault loop impedance (equivalent grid side impedance) for an installation (house load) that is connected to an EasySolar 24/3000/70-50 (which incorporates a MultiPlus 24/3000/70-50) as its sole source of supply?

Thank you for your time and help with this.

Multiplus-IIEasySolar All-in-One
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2 Answers
Matthias Lange - DE avatar image

The transformer is only used in inverter mode. If grid is available it will be pass-through directly to the loads via relays:

(This picture is in the manual and on the backside of the front panel.)


multi123000.png (141.3 KiB)
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Hello M.Lange,


Nice, thank you for sharing this.


Take care,

Karl T.

Rob Duthie avatar image

Hi Karl

Yes all Victron inverter chargers have an toroid isolating transformer. The impedance i don't know.

I just use a Fluke power multi tester for earth line impedance testing, as there is so many variables, any connections add to the impedance etc.

I had installation of a easy solar 12/ 1600/70 watt unit which had a loop line test of 18-20Ampsat the the end of circuit, or furthest socket outlet.

Measure with a meter to get a ball park figure Current = Voltage / Resistance = Amps


Regards

Rob D

NZ

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Hello Rob,
Thank you very much for taking the time to reply, it is a great help and much appreciated.


Are you able to point me towards Victron documents that describe or specify that a toroid isolating transformer is used and that perhaps might also list some specifications for it?

When you say loops test of 18 to 20 Amps is this perhaps 18 to 20 Ohms measured for the impedance of the at circuit that you tested? or does you meter list amps that you need to convert to Ohms using the equation you specified?

We are measuring around 8 to 9 Ohms at the EasySolar 24/3000/70-50 with a Fluke multi tester and about 12 at the site main switchboard.

Thank you for your time and help with this, take care and be Well,


Karl T.

Perth Australia

Hi Karl

It is a fact they use transformer, just take the cover off and have a look. I haven't seen any documentation yet. I have taken a few apart and they all have a transformer inside.

The Amps is calculated by the power multi tester and tells you in amps and resistance if required. This earth loop fault current is required so you know you have enough energy to trip the circuit breakers under fault condition's. As per AS/NZS 3000 regulations.


Regards

Rob D

NZ

Hello Rob,

That is great, thank you very much for further clarifying this, it is a big help.

That is useful to get the trip current also. We checked the screen of the tester and ours displays this also (you learn something everyday :) Than you).

Nothing beats looking under the cover in regards to the coil for sure.

It would be good if Victron provided more detailed specifications from this point of view for their transformers, however, also. Utilities in Australia (and New Zealand) have specific standards and test pass requirements with respect to the external part of the circuit connected to an installation. It appears to be an evolving territory as to how these carry over when an offgrid system displaces a grid connection.

Many offgrid inverters have challenges producing enough current to trip the full variety of circuit breakers than can be encountered in existing domestic and commercial installations.

Thank you for all your time and help with this, it is much appreciated.


Take care,

Karl T.