Weird Inverter Issues

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  • Battling BobBattling Bob Registered Users Posts: 20
    Re: Weird Inverter Issues

    This section of armored cable was the original genset connector that came with the Generac propane set we had near the house ten years ago. Three other gensets have been connected through that cable over the years. When I bought the big Hardy Diesel 15KW and put it out in my shop, I buried new #6 all the way to the house--but of course, spliced it into the old connector at a junction box for the last twenty feet into the inverter. Should have replaced that last section while I was at it, as this was a little too close to disaster for comfort.
  • RCinFLARCinFLA Solar Expert Posts: 1,469 ✭✭✭✭
    Re: Weird Inverter Issues
    This section of armored cable was the original genset connector that came with the Generac propane set we had near the house ten years ago. Three other gensets have been connected through that cable over the years. When I bought the big Hardy Diesel 15KW and put it out in my shop, I buried new #6 all the way to the house--but of course, spliced it into the old connector at a junction box for the last twenty feet into the inverter. Should have replaced that last section while I was at it, as this was a little too close to disaster for comfort.

    #6 will get a little warm at full load on a 15kW. I know you won't load it with SW's charging to that level but if you are turning on some other things during pass through like a hot water heater or A/C, plus full charging on SW, you might load it pretty good.

    I am using 10' SOOW for a portable connect cord. I could not find 4/4 SOOW locally so made due with 6/4 SOOW for the cord. It gets pretty warm when running full charging on two SW+5548's and running hot water heater at same time. I keep that cord limited to 50 amps on my 15kW portable (on wheels) generator. Because of the heavy insulation on SOOW cord, #6 should be limited to about 45 amps. I run the left over 13 amps over to my two SW4048's via second 8/4 cord in 30 amp gen outlet socket.

    The most I have ever pushed charging my 1100 AH batteries is a little over 200 amps @ 51 volts.
  • Battling BobBattling Bob Registered Users Posts: 20
    Re: Weird Inverter Issues

    Good points. I can say, though, that we have no self-initiating draws over four amps--that's what our washer, dryer and the combination of refrigerator and freezer draw if they happen to be running. Our water heater is a propane flash heater. I never charge at over 20 amps a leg--so at max, we'd be pulling 32 if everything happened to be running at the same time. (Actually, not even then--they're not all on the same leg.) I never fire up any of the big-ticket items, like my air compressor, with the genset running.

    So far, the new wiring hasn't shown any tendency to get warm at all. All the really weird symptoms--the voltage pushing and spiking, the sudden drop-off in amp draw of the bottom inverter, and all that, have disappeared. The system ticks right along, charging at more or less equal amps per leg, and dropping off like it's supposed to. I did pull the series stacking cable, as I have nothing in my system that requires 240.

    I did, though, have the bottom inverter kick out with an input relay failure last night when I shut down the genset with the fridge compressor running--so I'll be double-checking all my new wiring today to make sure I'm not melting somewhere else, because it didn't do that the first night after the rewiring job. Again, no input relay failure happens if I go to the trouble to turn off the fridge and freezer before I shut down the genset--but that's a pain, and surely there's a symptom there that needs to be attended to.

    As for Blackcherry04's excellent suggestion about zipping in to the repair shop with it--that's a 300-mile trip (at least) with a dubious outcome. There's a very well-known Trace fix-it man in Redmond, Oregon--but even he is having trouble coming up with some vital parts. I can get a rebuilt 4024 from him for $1800, but that doesn't seem to make sense compared to a little over $2000 for a Magnum Energy.
  • Battling BobBattling Bob Registered Users Posts: 20
    Re: Weird Inverter Issues

    The Schneider Electric Tech Support guy (yes, it IS possible to talk to someone!) addresses my "Input Relay Failure" issue--the one that occurs when I happen to trip the genset breakers to OFF when the refrigerator or freezer compressors are running. He says I can put a 50 Mfd 370 VAC motor run capacitor "across the load, in parallel." (I don't know if this smooths out any backfeed from a running compressor, or what.) So...given two terminals with multiple spade connectors on such a capacitor, do I simply splice into the appliance cord and wire the capacitor hot-wire in, hot-wire out from one terminal and neutral in, neutral out from the other terminal?


    Am hoping for the most basic, Tab A to Slot B, "adapted to the meanest understanding" advice here, folks. Am not generally conversant with theoretical shorthand.
  • RCinFLARCinFLA Solar Expert Posts: 1,469 ✭✭✭✭
    Re: Weird Inverter Issues
    The Schneider Electric Tech Support guy (yes, it IS possible to talk to someone!) addresses my "Input Relay Failure" issue--the one that occurs when I happen to trip the genset breakers to OFF when the refrigerator or freezer compressors are running. He says I can put a 50 Mfd 370 VAC motor run capacitor "across the load, in parallel." (I don't know if this smooths out any backfeed from a running compressor, or what.) So...given two terminals with multiple spade connectors on such a capacitor, do I simply splice into the appliance cord and wire the capacitor hot-wire in, hot-wire out from one terminal and neutral in, neutral out from the other terminal?

    Without knowing precisely what is the inductive load of the compressor, it can be dicey to place a cap of that size across it. 50 uF is likely more capacitance then the inductive compressor so it over compensates the power factor making the load alway capacitive (except during startup).

    You should stay away from perfect compensation (PF of 1.0). Generally less then 0.9 or greater then 1.1 is okay. Perfect compensation is resonance condition that can create high voltage ringing when compressor relay deactivates.

    http://www.famousparts.com/romorunca1.html
  • Battling BobBattling Bob Registered Users Posts: 20
    Re: Weird Inverter Issues

    The "full load amp" draw of the fridge compressor appears to be 6.5 amps--don't know whether that tells what I need to know or not. It appears to run at about 2 amps according to the SW's meters. As for power factor, and all that, I haven't a clue.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Weird Inverter Issues

    you can purchase a killawatt meter from our host or even some major stores like home depot or lowes. it will indicate power factor among many other useful things.
  • Battling BobBattling Bob Registered Users Posts: 20
    Re: Weird Inverter Issues

    So--finally got a Kill-a-Watt meter, which pegged the Power Factor on the fridge in a range from .98 to 1.0. The KAW is also showing me using about 109 watts with the compressor running, which seems awfully low to me--the inverter shows a load of about 3 amps when it's running.

    Anyway, applying this PF reading to the question about wiring the capacitor in parallel across the load... What would that accomplish, and what does the power factor reading tell me about the size of the capacitor to use?
  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Weird Inverter Issues

    PF above .9 is great, no need to do a thing.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
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  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Weird Inverter Issues
    So--finally got a Kill-a-Watt meter, which pegged the Power Factor on the fridge in a range from .98 to 1.0. The KAW is also showing me using about 109 watts with the compressor running, which seems awfully low to me-

    Actually for many of the newer fridges and freezers I've checked out, 109 watts isn't out of the ordinary, unless it's a power pig with ice makers etc. They sure don't suck power like they used to:D.
  • RCinFLARCinFLA Solar Expert Posts: 1,469 ✭✭✭✭
    Re: Weird Inverter Issues

    My large 27 cu-ft side-by-side with auto ice maker, that is about 4 years old, draws 126 watts while compressor is running. It averages about 1.1 kWH per day.

    Beside compressor consumption, there is also defrost cycle, ice maker tray ejection heater, fans, water valve solonoids and small timer motor.

    The only thing I can believe the refrig is involved with the inverter issue is providing enough loading on one side of stacked inverters to ensure that side is not backfeeding and releases, while the other inverter is backfeeding. With both stay connected to ACin, the generator acts as a coupling transformer, just moving power from one inverter to other inverter. With only one still engaged then it is truely pushing power into generator. Checkout the ACin green lights. Green LED on means power relay is still engaged to ACin.

    You would think the stacking interconnecting cable would provide info to ensure if one ACin releases the other should also. The stacking cable seems to only provide 180 deg sync clock when running off grid and when one inverter is turned off (either switched off or alarmed off) it turns the other inverter off.
  • Battling BobBattling Bob Registered Users Posts: 20
    Re: Weird Inverter Issues

    Yeah--I sure don't know what this means. The inverters aren't stacked any more, as one of the measures I tooks was to remove the stacking cable. I have never used the 240 volt capacity, so figured inverter interaction was one more variable to eliminate.

    What didn't change was that when the refrigerator compressor is running, it will kick the inverter into an "input relay failure" when I shut down the genset. If it is not running, shutdown is normal.
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