Magnum Inverter Fault question/ Generator rpm too high

camelback75
camelback75 Registered Users Posts: 4 ✭
in Solar Beginners Corner #1
I temporarily have a Generac 5K construction generator hooked up to my system while I'm waiting for my 240V conversion kit for my eco gen 6.5 k. After the generator runs for 15 minutes or so, it begins racing and I get a red fault light on the Magnum remote readout indicating my AC voltage is too high. Can someone help with this? I have a MagnaSine PAE series with a Midnite Classic. Thanks.
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  • firerescue712
    firerescue712 Solar Expert Posts: 95 ✭✭
    #2
    Re: Magnum Inverter Fault question/ Generator rpm too high

    Most construction grade generator outputs are not clean wave forms. Once you get the Generac online, the problem should go away. Just my 2 cents.
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #3
    Re: Magnum Inverter Fault question/ Generator rpm too high

    Sounds to me, if the generator is racing, the inverter is telling you the truth. I'd fully expect a racing genny to be putting out way too much voltage. I'd recommend getting rid of that generator before it burns out your equipment!
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  • camelback75
    camelback75 Registered Users Posts: 4 ✭
    #4
    Re: Magnum Inverter Fault question/ Generator rpm too high

    I believe the inverter, but this is the second generator I've tried and they have both done the same thing. (both construction type gens) I also have a Honda EM5000 I'm hooking up next week when I get the correct receptacle. I just have snow on my panels now. I expected to have my generac eco gen hooked up 2 weeks ago, but there was a problem with the 240v kit. Live and learn. So you think I'll probably be OK when I hook up the Honda?
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #5
    Re: Magnum Inverter Fault question/ Generator rpm too high
    camelback75 wrote: »
    I temporarily have a Generac 5K construction generator hooked up to my system while I'm waiting for my 240V conversion kit for my eco gen 6.5 k. After the generator runs for 15 minutes or so, it begins racing and I get a red fault light on the Magnum remote readout indicating my AC voltage is too high. Can someone help with this? I have a MagnaSine PAE series with a Midnite Classic. Thanks.

    These may be hard questions to answer, but does the generator start racing first and then the Magnum trips offline? Or does the Magnum trip offline and then with the load removed suddenly the Generac starts racing?
    How does the generator behave over 15 minutes if you leave it with no load whatsoever?
    How much power is the Magnum pulling at the time?
    If the generator is air cooled, it is possible that it is starting to overheat and it temporarily dumps the load and goes to a "fast idle" to get more fan cooling. Somewhere along the way in that process there might be a transient overvoltage which trips the Magnum off and requires a complete drop of input or other reset process to cut back in again?
    SMA SB 3000, old BP panels.
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #6
    Re: Magnum Inverter Fault question/ Generator rpm too high

    I guess you have a remote for the Magnum. Try cutting the charge Percentage back to say 30 % and let it run and stabilize the voltage past the time it would take it to start the surging. My guess would be the Inverter is varying the load on the generator with it's charger demand. I have a Magnum that does the same thing on the generator. I don't know if it's the charger or the temperature sensor in the inverter that causes the demand in the generator to oscillate and it will start a cycle that causes the same problem. If it stabilizes with the 30% , then try to increase it to where it's happy. Usually mine is about 80% or so.

    I am going to add this. Normally when the Inverter picks up the Generator the load will shift and the charger will ramp up slowly and the Amp draw is gradual enough where the generator RPM will adjust the change. When it changes it's demand ( whatever the cause ) with the surge there is no ramping up and down, it's a rapid change in demand on the generator. I have seen the demand go from 70 amps to over 140 amps on the chargers output in a second as a overshoot. This is what starts the cycle as the generator and the inverter fight each other over demand and output.

    Here is a tip from the Magnum manual about what may be happening. What it doesn't say is what happens when it goes out of Charger Back-off protection. To me it just goes wide open and causes the problem noted.

    "While charging, the unit may go into Charger Back-off protection
    which automatically reduces the charge current to the batteries. This
    is caused by: 1. The internal temperature is too hot – the charger
    automatically reduces the charge rate to maintain temperature; or,
    2. The AC input voltage falls below 85 VAC – the charger reduces the
    charge current to zero to help stabilize the incoming AC voltage."
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