question

yep avatar image
yep asked

Motor aircon running wild when generator starts powering the Victron Quattro


I have the following challenge:


When switching from battery operation to generator operation, the airco engine runs wild for a moment, sometimes resulting in a malfunction in the Quattro (and I am sitting stiffly upright in bed).


Situation without shore power and on battery operation:

Immediately when the generator is running AND gains access to the Quattro (via an external relay), the AC output on the Quattro supplies the voltage and frequency equal to the generator. The power will still come from the batteries! The generator will then run unloaded for a while (more voltage and higher hertz number). If after a few seconds the INTERNAL relay in the Quattro switches, it draws the power from the generator and no longer from the batteries. The drop in speed due to the load reduces the voltage and frequency. Delivery from the batteries is zero from that moment on.


How do I prevent AC out from passing through the higher frequency of the generator? Thanks in advance!

MultiPlus Quattro Inverter Charger
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3 Answers
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wkirby answered ·

The Quattro must synchronise with the incoming AC Voltage. The Frequency AND Phase must match before the internal bypass relay will close. A lot of current could flow, probably short circuit, if the internal bypass relay simply closes if even one of the above parameters is not the same as the incoming AC waveform.
So, what you have observed is normal. The Quattro will frequency shift to match the phase angle and frequency of the incoming AC waveform. With the internal bypass relay still open, the Quattro will track the AC waveform of the incoming AC for a while.
At this stage it is not passing the incoming AC through, it is still powering the load with the batteries to get the best match to the incoming AC until it is satisfied that it is safe to close the bypass relay and then allow the incoming AC through. This synchronisation process is most necessary and cannot be prevented.
On some occasions the Quattro cannot lock to the incoming AC because it is out range or it cannot track it and then it presents an error.
The increase in frequency is going to have more of an effect on the RPM of the air conditioner motor than the Voltage.

Surely the generator should not be over RPM even with no load. I think that is the source of the problem overall.

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yep answered ·

Hi Wkirby,


Thanks and totally clear.

I will try a different solution.


Regards,


Yep

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yep answered ·

Problem solved.

When the generator has warmed up, a signal from the power box activates a relais which connects the generator with AC-in on the Quattro.

That same signal activates another relais with a timer which disconnects the motor in the airco unit for about 10 seconds. In the meantime the internal relais in de Quattro is already closed and after that the airco motor starts.

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