[RE-wrenches] Generator surging

[Mac Lewis]

Do you hear audible changes in generator rpm?

I believe that generator has the RDC2 controller that you can log into with
Sitetech. There is a parameter that adjusts the sensitivity of the governor
(I can dig up the exact parameter later). A Kohler tech can adjust this and
I'm betting it will help, or at least rule out the generator control loop.

What's your altitude?



On Thu, Mar 19, 2020, 1:20 AM William Miller <william at millersolar.com>
wrote:

> Mac:
>
>
>
> I know well what the AC input mode is.  This is the project that had the
> excessive THD on the voltage waveform (>26%f).  Here is a link
> <https://millersolar.com/MillerSolar/case_studies/25_GFI%20Tripping/GFI_Tripping.html>
> to the case study.
>
>
>
> As you can see, we resolved the problem by changing the AC input mode to
> Backup.  After recent rains started and generator run became necessary, the
> client started noticing flickering of lights and refrigerator operation was
> unreliable. We examined the E-Gauge data and could see rapid fluctuations
> in the generator output.  At one point we saw generator power range from
> 19kW to 12Kw and back in about 2 seconds.
>
>
>
> We isolated the generator into a load bank and it was rock solid.  We
> tried lots of things but when we reconnected the generator to the Radians
> and switched to the Radians to Generator input mode the surging stopped.
> Unfortunately, the Generator mode causes tons of THD, as noted in the case
> study.
>
>
>
> So we can’t use Generator because of THD, and we can’t use Backup (or
> Support or UPS) because in all these modes the generator surges.
>
>
>
> By the way, this is a newish Kohler 30RCL.  This should be a rock-solid
> match to a 24 kW Radian system.
>
>
>
> Like I said, we tried lots of things.  What stopped the surging was to
> open the AC input breaker to Inverter 1.  It did not help to open the input
> to Inverters 2 or 3.  I don’t have a clue as to why this is so…
>
>
>
> We tried taking Inverter 1 out of the system--moving inverter 2 up to
> Master and Inverter 3 to Slave 1.  The generator still surged. So if anyone
> started to think Inverter 1 was the problem, this was not confirmed.
>
>
>
> We are certain the neutral bonding is exactly as it should be.  We tripled
> checked this when chasing the THD problems.  We also adjusted input AC from
> 30 to 50 (per port), no improvement.
>
>
>
> I must say Outback has been very available to us as we try to figure these
> problems out.  I am fortunate that I am working with a senior engineer.  We
> are both currently stumped, but we are going to consult again tomorrow and
> see if any other ideas come to us.
>
>
>
> Thanks everyone for the input.  More soon.
>
>
>
> William Miller
>
>
>
>
>
> *From:* RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] *On
> Behalf Of *Mac Lewis
> *Sent:* Wednesday, March 18, 2020 6:35 PM
> *To:* RE-wrenches
> *Subject:* Re: [RE-wrenches] Generator surging
>
>
>
> Hi William,
>
>
>
> Do you know what your AC input mode is?
>
> I'd try playing with this mode.
>
> If you have a generator, I'd try switching between "generator",
> "support".  You may quickly see a difference.  There is a small diode
> symbol that shows up on the Mate3s screen during generator charging.  I
> don't fully understand what that means but I know that it can affect how a
> generator works with the Radian.
>
>
>
> Also, you may try lowering the charging current and see how the generator
> responds.
>
>
>
> What type of generator?  Whats your AC input limits?
>
>
>
> On Wed, Mar 18, 2020 at 6:56 PM Jerry Shafer <jerrysgarage01 at gmail.com>
> wrote:
>
> Adjust the generator max output in the outback down and see what happens
>
> Jerry
>
>
>
> On Wed, Mar 18, 2020, 4:04 PM William Miller <william at millersolar.com>
> wrote:
>
> Friends:
>
>
>
> I have a 24kW Radian system that is acting up.  The problem is when the
> generator is running, it surges.  Voltage and power go up and down.  We
> connected the generator to a load bank and there was no surging.  This
> makes me think the problem is in the Radian system.
>
>
>
> Has anyone else experienced this?
>
>
>
> Thanks in advance for any input.
>
>
>
> William Miller
>
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> --
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>
> Mac Lewis
>
> "Yo solo sé que no sé nada." *-Sócrates*
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