Generator Goes Over AC Input Current Limit

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alia-rahim asked Jan 2, '24

Generator Goes Over AC Input Current Limit

A split phase system with 2 x Quattro 15000 paralleled as master and slave. The AC1 input current limit in Quattro is programmed to 35A (See picture below).

In total is 70A current input from the generator when generator runs.

The generator is only called at 25% SOC to charge the batteries and supply load at the same time.

The issue here is that when the generator runs it pumps in at 74A when load is high. Why is it not limiting to 70A? Why is the Quattro allowing more current input than whats limited?

Please assist or any ideas would be much appreciated.

Generator input current

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Answer 1 · 2024-01-02T05:22:40Z

Alexandra answered · Jan 02 at 05:22 AM

Does turning it down a bit more not help? That is always an option.

It can be many reasons why it is not on point, one is current sharing on a parallel setup, the other is the 'noise' on the AC from the generator.

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alia-rahim commented · Jan 03 at 04:28 AM

The current setup is tripping our 80A cb. That also means the generator current input went higher than that 74A. So we had to change the input current limit down to 60A.

However this could also mean when the load is high it might still ignore the current input limit and draw higher than 60A. Any thoughts?

Also, could you please explain further on the 'noise' you are referring to?

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Alexandra ♦ alia-rahim commented · Jan 03 at 06:50 AM

RMS readings and peaks are different.

Also if the breaker is getting hot it will trip.

Harmonic distortion. Is one. Also usually a breaker is sized 1.25% higher than the amps expected to be drawn through it.

Weak AC is a good suggestion from @CM.

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Answer 2 · 2024-01-03T04:37:05Z

CM answered · Jan 03 at 04:37 AM

Is weak AC selected on charger side ?

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alia-rahim commented · Jan 04 at 12:50 AM

@Alexandra @CM yes

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CM alia-rahim commented · Jan 04 at 08:26 AM

I want to believe the generator set is having a hard time keeping up with the 400amps current plus AC loads at the same time , probably reduce the input current by 5 and 10 until you get a favorable operating range that doesn’t trip the breaker , also what’s the frequency when the gen is running at those heavy loads ?

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alia-rahim CM commented · Jan 05 at 12:53 AM

50-51 Hz (rounded up from two decimal points)

For the time being the current input limit has been reduced from 70A to 60A. We will have to keep monitoring it.

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