3-phase quattros switch off under load

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mufassa asked Dec 11, '22

3-phase quattros switch off under load

Going through some testing on a recent install. 3 Quattros (15k) in 3-phase config. If there is a small load, i.e. 3kW, and the device is set to 'Off' from 'Inverting' on the Cerbo GX menu, supplied voltage seems to go crazy for a fraction of a second (contactors bounce, lights flicker, etc) before the inverters switch off. All loads on AC-1 out.

No such behaviour happens if I open the contactor under load between AC1-out and dist board, and switching on under the same load exhibits no bad behaviour

is this expected?

MultiPlus Quattro Inverter Charger

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Answer 1 · 2022-12-11T17:52:13Z

nickdb answered · Dec 11, 2022 at 05:52 PM

Why on earth are you doing a test like that?

Grid isn’t synced so it will be a dirty shutdown.

Sounds pretty normal for those conditions.

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mufassa commented · Dec 11, 2022 at 06:54 PM

The shutdown - i.e. Quattro set to off - is done from the GX menu.

Why would grid sync be an issue? AC1-in relays open in Inverting setting, how is grid in any way involved?

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Answer 2 · 2022-12-11T18:03:48Z

Alexandra answered · Dec 11, 2022 at 06:03 PM

If you have a GX and ideally you should, you will have errors like unexpected device shut down error 1. error 10.

But a three phase should be shut down from a GX device because of the phase and grid synchronization.

But yeah a dirty shutdown.... Not cool. You can install the safety switch assistant and an emergency switch if rapid shut down is needed.

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Answer 3 · 2022-12-11T19:52:19Z

Kevin Windrem answered · Dec 11, 2022 at 07:52 PM

If I understand correctly, the OP is turning off the Quattros from the GX menu. Quattros are inverting (GX device is Inverter Only or no AC input) then the mode is switched to Off. This does not seem like a "dirty" shutdown to me. Should be clean without any voltage spikes on the Quattro output.

The only thing I can think of is the load is sending power back into the Quattros when it is turned off. I think that would take more than an inductive load but could be wrong.

What happens if you use the switch on the front of the main Quattro?

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shaneyake commented · Dec 11, 2022 at 11:47 PM

This is my understanding too. I would think it is inductive loads interacting with the transformers in the inverters.

Tuning off inverters from GX normally works well. Possibly check firmware on the inverters to make sure they are all the same.

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