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generator problem

Discussion in 'Home Power and Microgeneration' started by Cat 22, Oct 24, 2010.

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  1. Cat 22

    Cat 22 Guest

    I have a 5700 watt Mcculloch FG5700AK generator. When its under a
    good load its ok,but when the load is light/none the freq jumps way
    up. The speed sounds about normal, but the frequency measures 180 HZ
    at very light/no loads and under quarter load or so the freq drops
    back to close to 60 HZ.Output voltage is ~120vac and it does vary
    some depending on load. I discovered this when we had a blackout and
    i tried to run my new furnace on the generator, it would show fault
    led's if the fridge kicked on (momentary voltage sag). or if nothing
    else was running besides the furnace.
    I measured the noload freq with a fluke meter t ~180Hz- and at first
    i thought i just didnt have a connection to the meter probe, but
    under load (the lowest load i tried and still got 60Hz was 700 watts)
    it drops back to right about 60Hz
    Its a new Coleman CP9C Echelon furnace, my old carrier weathermaker
    8000 worked fine on the generator. One big difference is the Coleman
    draws very little power.

    I had thought abut putting this on the furnace circuit:
    "Tripp Lite LC 1800 Line Conditioner / AVR System LC1800"
    or maybe this:
    "Tripp Lite LCR2400 Line Conditioner - Automatic Voltage Regulation
    with Surge Protection"
    Would an ordinary Computer 1200VA UPS do?

    Any ideas? Why does the freq act like that? Time for new generator?

    Thanks
    Cat22
     
  2. Cat22

    Cat22 Guest

    I think you are right, the fluke is reading harmonics or something when
    there is little to no load. All my other stuff (2 fridges a freezer some
    cfl lights and a microwave) run fine, its just this furnace that seems
    sensitive to the generator output.
    What do you think about either of the two items i listed above to help
    clean the power? Would I be wasting my money?
    Thanks
    Cat22
     
  3. Try a resistive load in parallel with the furnace. Such as a 100w
    incandesant bulb.
    If you have a Kill-a-watt, see what the Power factor is of the furnace.
    The 100w bulb might pose enough of a resistive load to the generator to
    make things stable.
    I agree with Ralph that the brushes or slip rings may be worn or dirty
    causing havoc with the generators exciter circuit. But it could be that
    furnace motor has lousy PF. Is it a capacitive start or does it have a
    start winding?

    Cheers
     
  4. Josepi

    Josepi Guest

    Some things I observe.
    The frequency is probably only a function of spikes (as another poster
    stated) scrwwing with the zero crossing detector in the Fluke. Since the
    freq. measured is a direct 3rd harmonic I would say that is a definite.
    Heavier loads tend to disapate the 3rd harmonics or bury it in bigger
    amplitude fundamentals for the meter.

    Since you have a mechanical waveform generation, if your frequency varied
    you would hear the motor increase in speed by that ratio. I doubt you are
    hearing that freq. change.


    Are there sepearte feedback sensor inputs for the generator regulator? Not
    likely but, If so some other options come to mind.

    The UPS may have more harmonics than your genny. Some fo these cheaper units
    give off slightly filter squarewaves.

    The line filters may help but I am not familiar with those ones usage or
    response.

    Do you have a scope with memory?


    I have a 5700 watt Mcculloch FG5700AK generator. When its under a
    good load its ok,but when the load is light/none the freq jumps way
    up. The speed sounds about normal, but the frequency measures 180 HZ
    at very light/no loads and under quarter load or so the freq drops
    back to close to 60 HZ.Output voltage is ~120vac and it does vary
    some depending on load. I discovered this when we had a blackout and
    i tried to run my new furnace on the generator, it would show fault
    led's if the fridge kicked on (momentary voltage sag). or if nothing
    else was running besides the furnace.
    I measured the noload freq with a fluke meter t ~180Hz- and at first
    i thought i just didnt have a connection to the meter probe, but
    under load (the lowest load i tried and still got 60Hz was 700 watts)
    it drops back to right about 60Hz
    Its a new Coleman CP9C Echelon furnace, my old carrier weathermaker
    8000 worked fine on the generator. One big difference is the Coleman
    draws very little power.

    I had thought abut putting this on the furnace circuit:
    "Tripp Lite LC 1800 Line Conditioner / AVR System LC1800"
    or maybe this:
    "Tripp Lite LCR2400 Line Conditioner - Automatic Voltage Regulation
    with Surge Protection"
    Would an ordinary Computer 1200VA UPS do?

    Any ideas? Why does the freq act like that? Time for new generator?

    Thanks
    Cat22
     
  5. Guest

    a steady load, like lights, to get the total load to 700 should allow
    the furnace to run just fine. DON'T let the refrige cut in while the
    furnace is running.

    Only a dual conversion UPS (full online) big enough to handle the
    furnace would do any good.
     
  6. Bruce Gordon

    Bruce Gordon Guest

    What you need is to run the power to the furnace thru an Isolation
    Transformer, which will knock down the spikes in the power from the
    genset. We used to have a whole bunch of SOLA Power Conditioners that
    were BIG Heavy Ferro-Resonant Transformers with an LC Tuned Secondary
    Winding, to take the Spikes out of our Generated Power for a big Xerox
    Copy Machines and other sensitive loads.
     
  7. Cat22

    Cat22 Guest

    I'll rig it up and see what happens, I have a small electric heater i
    can use to load it also i can vary that load down to 750 wats
    I do have a kill-a-watt, My feeling now is that its the dip when
    something comes on that is causing the furnace to drop out

    Cat22
     
  8. Cat22

    Cat22 Guest

    its a Coleman CP9C060B12 gas furnace.
     
  9. Cat22

    Cat22 Guest

    the furnace specs say its 7.0 amps total unit draw
    The motors are variable speed, DC i believe.
     
  10. Cat22

    Cat22 Guest

    My installer told me before i bought the furnce that it would run on a
    generator, the guy who came to look at what was happening when i called
    them said it should run on a generator but he didnt know why it wasnt
    They do, everything i throw at it works except this new furnace, the old
    1995 carrier weathermaker 8000 had run on it several times
     
  11. Cat22

    Cat22 Guest

    how can i determine if I have that?
     
  12. Liquid80

    Liquid80 Guest

    responding to http://fuelzilla.com/homepower/generator-problem-54076-.htm
    Liquid80 wrote:
    We're you able to figure out the issue with your furnace and generator?

    I'm in NJ and was out of power from hurricane sandy for 5 days with a sick
    1yr old.
    I am looking to get a generator that will work with the same furnace that
    you have
    so I don't have to go through this again in the future if it ever happens
    again. I'm
    thinking of making a connection from whatever generator I get directly to
    the
    circuit breakers in the house with something like an interlock kit
    (interlockkit.com) but I want to know that the furnace will run correctly
    before I
    make the investment.
    My furnace is brand new Coleman Echelon 9.c.
    I'm looking at either gas or propane generators.

    Any advice is greatly appreciated!
     
  13. Neon John

    Neon John Guest

    I live way back in the mountains, literally 20 miles from anywhere.
    Power outages are a regular occurrence thing here. I messed around
    with several "solutions". I built this 10kW generator for summer use
    to run my AC.
    http://www.neon-john.com/Generator/Generator_home.htm
    (bottom of the page.)

    I used this generator when I was in the restaurant and concessions
    business and used it to power my house in the winter where I heat with
    propane and wood.

    http://www.neon-john.com/Generator/Quiet_pack_55G/Quiet_home.htm

    This is a very quiet generator and will almost start my 2.5 ton
    central AC unit but not quite.

    Like the other generator, it required me to roll it outside, connect
    the cord to the dedicated outlet, then lug the fuel containers. As
    I've gotten older, that's gotten harder to do so a year ago I solved
    my problem once and for all. I installed this generator

    http://www.norwall.com/products/Gen...dPackaged-w{47}200-Amp-Service-Rated-ATS.html

    and a 500 gallon propane tank. Norwall seems to have the best prices
    every time I look around but do shop a bit.

    I have about $4000 in my installation. I installed the generator
    myself but had a contractor do the utility tie-in. I could have done
    it myself in TN but the local inspector has a rep for harassing DIYers
    so I paid the guy a little and got a hassle-free inspection.

    This is what I should have done years ago. When the power goes out,
    the generator's control system waits 10 seconds to make sure it really
    is an outage. It cranks and closes the transfer switch 5 seconds
    later. This is especially nice when the power goes off when you're in
    the middle of a wellpump-fed shower!

    Our longest outage since I installed this system was 4 days after a
    tornado. Middle of summer, hot and humid. My AC worked just fine so
    I was cool, comfortable and clean (electric well pump, remember).

    At the light load my house normally presents, my unit uses between 1/4
    and 1/2 gallon of propane an hour. That's around 1000 hours or 41
    days of capacity, assuming no refill. I keep the tank full.

    I do not recommend natural gas. First, it makes less power than
    propane. Second, during mass disasters such as just happened, the
    natural gas supply frequently goes down because the pumping stations
    are taken out. Plus the little bit of survivalist in me wants total
    control over my fuel source.

    If you don't like the looks of a propane tank, have a direct burial
    one installed. Then only a little dome sticks up out of the ground.

    Something else you might consider. I moved my vital loads
    (refrigerators and lights and wood stove fan) to a sub-panel and power
    that panel from a 5kW UPS that I scrounged from a data center. I also
    scrounged enough batteries (they change them out on a schedule, not
    when they go bad) to power my "vital bus" for 48 hours. Before I
    installed the Guardian, that carried me for a day or so without having
    to get the generator out.

    With the Guardian, when I don't need AC, I only run it about half the
    time. The rest of the time I run on UPS. That way I can sleep at
    night without the generator noise and still have everything I need
    except hot water and the well pump. I have a large enough tank on the
    well pump to last a day as long as I don't flush the toilet or try to
    take a shower.

    Living back in the hills like I do, I've learned to incorporate
    redundancy into everything vital. I still have the diesel generator
    if the Guardian fails. I have the UPS. I primarily heat with wood
    but I have a little propane heater hanging on the wall for in case I
    run short of wood or just don't feel like lugging it in. My stove's
    electric but I have a propane powered Coleman stove in the closet so I
    can cook when the generator is not running.

    My advice is don't mess around with jerry rigs and do it right.
    Install a propane powered automatic generator. I like my Generac but
    the Kohlers are nice too. Do NOT get a Coleman. They are LOUD. My
    neighbor bought one based on price. That lasted one power outage. He
    replaced it with a Guardian.

    One last thing. Mount the generator above the flood plane. On the
    coast of NC where they put cabins up on 20 ft stilts, I've seen
    standby generators on cantilevered platforms off the side of the
    cabin.

    The propane tank has to stay on the ground and flooding won't hurt it
    but it does have to be strapped down (use mobile home anchors) or it
    will float away!

    John
    John DeArmond
    http://www.neon-john.com
    http://www.fluxeon.com
    Tellico Plains, Occupied TN
    See website for email address
     
  14. Vaughn

    Vaughn Guest


    Good thoughts, but natural gas sure is convenient if your gas system
    survives your particular natural disaster. The last four hurricanes
    here haven't caused a bobble in our NG service. After each hurricane, I
    have had all the fuel I wanted without standing in one damn line!

    So what happens if the natural gas system goes out? Well I'm a bit of a
    survivalist also! That's why I have four 100# propane tanks and a
    little trailer to take them for refilling should it ever become
    necessary. Turn off the NG valve, turn on the propane valve, and make
    one quarter-turn mixture adjustment and I am back in business!

    Still, I envy Neon John's buried tank.

    Whatever you decide, think about your fuel supply and know how much fuel
    your generator takes per hour. Then do the math! Figure both the cost
    of running your generator through a long outage and how long you can run
    with available fuel. Then either have a realistic plan regarding where
    your fuel will come from after a disaster, or have a sufficient supply
    stored away. Propane has the advantage that it never goes bad. Diesel
    stores longer than gas, but it still can have issues.

    Vaughn
     
  15. Bruce Gordon

    Bruce Gordon Guest

    My Brother, "The Engineer" is rebuilding his home in a mid-sized city in
    Utah. He installed a 1K USG Propane Tank, underground in his yard, and
    has NG piped into the house. He also has a 55 USG Drum of 80/87 Aviation
    Fuel, sitting on steel stilts, and bolted to the floor and Garage Wall.
    All this is to support his Generac 20Kw TriFuel Genset that lives in the
    SECURE Generator Room, under part of the Double Garage ground level
    Floor. Primary Fuel will be the NG Feed from the local NG Pipeline.
    Should that fail then he can switch, the Genset, the Kitchen Stove, the
    house H&AC, Hot Water Heater, and the Cloths Dryer, over to the Propane
    Tank. The 80/87 AvGas is for the vehicles, and if in dire straights, can
    feed the Genset. The Genset can run the WHOLE House, or can be used to
    charge an Outback 3648 Inverter with 2500 AmpHours of Battery that also
    can run the whole House. The Inverter, Charge Controllers, & Batteries,
    live in a Separate Electrical Room next to the Generator Room, under
    another section of the Garage Floor. He has twin Outback MX-80 Charge
    Controllers, that ties his 6Kw of Roof Mounted Solar Panels, to the
    Battery Bank. Barring a Nuclear Air Strike in his valley, he is setup
    for just about any eventuality. Just Say'en..... YMMV....
     
  16. David Lesher

    David Lesher Guest

    Your gas utility goes to to GREAT lengths to keep the gas from
    failing. If it does, it's an enormous economic hit to them.

    I recall ~50 years ago the utility lost gas pressure to a
    part of a suburb. They had to go to each house, shut off the
    gas at the meter, then restart the gas in that neighborhood
    and bleed. Then go to each house again, open, and light every
    appliance. Repeat in neighborhood after neighborhood.
    It took days.

    When PG&E blew up San Bruno, parallel pipelines kept the
    Peninsula and San Francisco going; in NTSB testimony PG&E said
    restarting the city alone would have taken three+ months.

    When max usage draws heavily on a system, the utility can add some
    higher-Therm propane to the mix.

    While gas transmission pipelines do have compressors, often they
    are cannibals, burning some of the gas they ship. In any case,
    the utility has local storage.

    As I recall, much of NYC lacks natural gas distribution, but in
    places where disasters have hit, the gas is often the utility that
    keeps going.
     
  17. Youngster. Ptfui. How's about when they switched over
    from (so-called) "Town Gas" to natural gas. Same problem.
    Had to shut down everyone and then reconfigure all
    those burners...

    Or... when the parts of the US that were transferred
    and merged into the sixty cycle electric grid...
    Only a small portion of NYC is natural gas deprived. There
    are areas next to the ocean where buildings were badly
    damamged enough that the utility shut off all fuel
    to the neighborhood.

    There are similar, and more widespread, issues where
    lots of NJ and Long Island just Isn't There anymore.

     
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