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lucasteixeira avatar image
lucasteixeira asked

Victron Quattro 5000 VA with Contactors

Hello everybody,


I intend to install 3x Victron Quattro 5000 VA / 120V/48 V with an Automatic Transfer Switch. I know that the inverter has this feature, however it is more expensive to adjust all of my client's panels than just adapting our circuit to this electrical installation.


The single-line circuit is described below:


k is the command signal to open or close the contactors.


Should I be worried about transients that may harm the inverter and/or loads?


Thanks in advance!

MultiPlus Quattro Inverter Charger
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3 Answers
wkirby avatar image
wkirby answered ·

When the grid fails, be aware that by default there is a N - E relay that closes on the output of the Inverter.
You are also assuming responsibility for anti-islanding now since it out of the control of the Victron equipment. Any failure of latency of those contactors (top and middle) could cause backfeed.

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lucasteixeira avatar image lucasteixeira commented ·

Thanks for your reply.


When you say N-E should it be N-O (normally-openned relay)?


I will ask to the panel manufacturer to assure synchronism between the two contactors.



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markus avatar image markus ♦♦ lucasteixeira commented ·

Neutral to Earth bridge is meant.

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lucasteixeira avatar image lucasteixeira markus ♦♦ commented ·

Thank you!

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Johannes Boonstra (Victron Energy Staff) avatar image
Johannes Boonstra (Victron Energy Staff) answered ·

The remark on the ground relay is correct, in this case the unit will remaining to see the grid voltage so will remain in charger mode and therefore have its ground relay open. this is not what is supposed to happen as its unknown what kind of grid is handled and is the load is on grid or inverter. Beside this the fast transfer between inverter/grid may be an issue for some loads as it is possible to switch from inverter (which is rejecting the grid or had not synced yet ) to grid,

there can be a jump in freq/V.


PS the remark on the anti islanding isn't valid. ONLY when the system is setup to inject power into the grid this is required.

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lucasteixeira avatar image lucasteixeira commented ·

Thank you for your reply.


The command panel will open the upper contactor as it will close the lower contactor when the grid fails.


So, Quattro's AC-in-1 should notice as well the failure of the grid.


I'm studying installing another Normally Closed contactor at AC-in-1.


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pietskille avatar image
pietskille answered ·

I'm running Quattro V1 with this bypass-contactors (20ms reaction time) setup since 2013, no problems so far. Important pointers: break-before-make the two alternating contactors, so as to prevent grid feedback to AC1-OUT which may damage equipment. Ensure that load does not exceed inverter capacity when breaking the grid "bypass" contactor & making the "pass-trough" contactor: it gives the Quattro room & time to sync properly even if it is seemingly already in sync before the changeover.

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