question

ripper avatar image
ripper asked

Can Quattros in 3 phase change frequency easily?

I might be interested in repowering a diesel electric plant into running a 3 phase Quattro setup running off partly solar. It would require the electric motor to run at different speeds. The current diesel can run 1500, 1600, 1700 and 1800 rpm or 50, 53.3, 56.6 and 60 Hz at the touch of a button.

Is there any way to get the increments off the quattros?

Can I change the frequency under load?

Alternativly power will be produced by a standard 50Hz generator on cheaper fuel than regular diesel. Can the Quattro make 60Hz out of 50Hz incoming? Or does the generator need to charge the batteries for the inverter to make 60Hz?Then it might get too inefficient overall.

Do I need the computer to adjust each unit individually or is there another externally signalled way? Its gonna be 3 to 9 15kva Quattros depending on the plant size.


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

The frequency is to be set at installation time and it is not intended to be continuously variable on demand. Indeed they are engineered to maintain a stable frequency when inverting.
Once connected to the grid or generator, the bypass relay closes and the Quattro will lock to the input frequency, which needs to be in the range that the Quattro is configured for. It doesn't take in 50Hz and then output 60Hz.

You really need to be using a VFD to drive your motor, a proper motor drive with continuously variable frequency to regulate the motor speed - at the touch of a button. There are three phase input models available for large motors.

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Kevin Windrem avatar image
Kevin Windrem answered ·

Victron inverter/chargers can be set to accommodate a wide frequency range (45-65 Hz if I recall correctly). However any frequency change on the input may cause an AC input disconnect until the inverter/charger relocks to the new frequency. During that time, the inverter will run off batteries at the previous frequency. If the frequency changes very slowly the inverter might track it.

In order to make 60 Hz out of 50 Hz, you need separate charger and inverter like the Victron Phoenix lines. The chargers keep the battery bank topped up and the inverter always runs off the batteries. AC output voltage and frequency are then independent of what's coming in.

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ripper avatar image
ripper answered ·

Sadly a frequency converter would add 15 grand easily to the bill. Fuel is too cheap to make that viable... Cheers guys.

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