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  1. #14
    Join Date
    Apr 2005
    Location
    Tampa, Florida
    Posts
    1,634
    Quote Originally Posted by motoguy128 View Post
    a 2000 Watt inverter generator is around $1300-$1500. A 6.5kW is a little overkill for just running a couple lights and the furnace. Plus a 2000 Watt unit is portable enough for camping, tailgating and other uses. .
    I hope people don't actually pay that much. The reputable dealers in town weren't selling them for that much even post-hurricane. I bought mine from Mayberry's (google it) as have a couple of other locals. Couldn't be happier. I've heard good things about the Yamaha inverter generators as well but haven't come across one yet.

  2. #15
    Join Date
    Feb 2003
    Location
    Huntsville,AL
    Posts
    4,125
    what is an 'inverter generator' ??
    this seems to be an oxymoron --

    a generator is a device driven by an engine [usually] to make electricity;
    an inverter changes direct-current to alternating-current type electricity.

    BTW, during an event such as an ice storm,
    one can hookup a furnace much easier & cheaper than having a transfer switch!
    get a quote from 'sparky' or HVAC tech for such.
    the Pros have such info.

    BTW, I consider an event to be an emergency when lives are at risk immediately; else it is just an undesireable event.
    Last edited by cem-bsee; 02-04-2009 at 03:18 AM.
    harvest rainwater,make SHADE,R75/50/30= roof/wall/floor, use HVAC mastic,caulk all wall seams!

  3. #16
    Join Date
    Jun 2007
    Location
    louisville ky
    Posts
    107
    if i tell them i hooked the furnace to the generator will it void my warranty? i have a gooman furnace.

  4. #17
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    Quote Originally Posted by tpa-fl View Post
    I hope people don't actually pay that much. The reputable dealers in town weren't selling them for that much even post-hurricane. I bought mine from Mayberry's (google it) as have a couple of other locals. Couldn't be happier. I've heard good things about the Yamaha inverter generators as well but haven't come across one yet.
    The Honda and Yamaha which use inverters, and automatic "eco" throttles that actually modulate the RPM at part loads, use much less fuel and are much quieter. Yes you can get a basic 2000Watt gernator for almsot half that price.

    There are several other methods of generating a sine waveform from a DC generated power. I don't remeber the exact terms, but cheaper generators use less expensive methods to convert DC to AC than inverters and therefore have imperfect sine waves that may cause problems with some electronics without their own power conditioner.

  5. #18
    Join Date
    Apr 2005
    Location
    Tampa, Florida
    Posts
    1,634
    Quote Originally Posted by cem-bsee View Post
    what is an 'inverter generator' ??
    this seems to be an oxymoron --

    a generator is a device driven by an engine [usually] to make electricity;
    an inverter changes direct-current to alternating-current type electricity.
    You're almost there. These inverter generators have high-speed alternators built into to their flywheels and the output from the engine generator is actually DC voltage, just like your car's alternator. They then (internally) strap a pure sine-wave inverter to that DC generator and have that create the AC output. The inverter has direct control over the throttle and varies the RPMs based on load, which means great efficiency and a smaller, lightweight generator. Since the AC is generated solely by the electronics of the inverter, you always get perfect 60 cycle pure sine-wave AC power.

    Compare this to a traditional generator where you have an engine, governor, and separate generator portion. These generators must remain at some multiple of 60Hz constantly to maintain the 60Hz on the AC output. They also depend on a crude mechanical governor to maintain the 60Hz which is why they rarely put out a true 60Hz. No load or full load, they'll be cranking away at the same RPMs (usually 3600 RPM for the cheapies, 1800 RPM for the better-quality pad-mount generators). Most of the cheap traditional generators also don't put out a true 120v RMS either, usually they're a bit weak on the peak voltage.

  6. #19
    Join Date
    Nov 2008
    Posts
    1,673
    "An emergency is a situation which poses an immediate risk to health, life, property or environment."

  7. #20
    Join Date
    Jul 2007
    Location
    Tulsa, OK
    Posts
    986
    Only run the gas furnace if less than 7,000 watt generator.
    That said even the best of intentions from Honda and others that are considered portable on the spot for extension cord hook up use all require non dirty power for control boards and a good ground that is isolated to an earth ground as well as frame ground. Remember if in fact (which you cannot) determine is the correct rotation when started. Small units just start and can go the wrong direction which is reversed polarity issues and one has a control board code-out.

    Finally just put a 370v 7.5 uf cap inline to the black hot feed into the heater and it cleans up dirty power. Do the best tweaking of the governor to maintain at least a minimum constant 110v at 58 Hertz but under 128v at 62 Hertz ***UNDER FULL LOADING, DO NOT USE ECONO MODE IF IS AN OPTION*** and only run not more than two inductive motor loads as appliances together such as the heater and the refrigerator together. "The TV is a resistive load so go for it and wi fi !!!!!!

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  8. #21
    Join Date
    Jun 2007
    Location
    louisville ky
    Posts
    107
    if i tell them i hooked the furnace to the generator will it void my warranty? i have a gooman furnace.

  9. #22
    Join Date
    Feb 2003
    Location
    Huntsville,AL
    Posts
    4,125
    the last I heard, an alternator produces alternating current, as in my cars made after about 1975.

    before that, my cars had generators, giving direct current.

    I have replaced a bad diode inside an alternator which quit charging my dc battery.

    so, are the <$1000 'emergency' generators producing a/c or d/c within the windings?
    from HONDAPOWEREQUIPMENT.com:
    How does the inverter work?

    Honda 's inverter technology takes the raw power produced by the generator and uses a special microprocessor to condition it through a multi-step process.

    First, the generator's alternator produces high voltage multiphase AC power. The AC power is then converted to DC. Finally the DC power is converted back to AC by the inverter. The inverter also smoothes and cleans the power to make it high quality. A special microprocessor controls the entire process, as well as the speed of the engine.

    Honda uses only high quality inverters in our generators, which produce stable, consistent power.

    The end result? Clean enough power to run even the most sensitive electronic equipment.
    ***
    I wonder what is 'high voltage' to Honda? [for me =>69kV, per IEEE].
    ***
    that site suggests sizing the generator with more than 2.5x the furnace blower wattage --
    Last edited by cem-bsee; 02-05-2009 at 11:30 PM.
    harvest rainwater,make SHADE,R75/50/30= roof/wall/floor, use HVAC mastic,caulk all wall seams!

  10. #23
    Join Date
    Jun 2007
    Location
    louisville ky
    Posts
    107
    Quote Originally Posted by cem-bsee View Post
    the last I heard, an alternator produces alternating current, as in my cars made after about 1975.

    before that, my cars had generators, giving direct current.

    I have replaced a bad diode inside an alternator which quit charging my dc battery.

    so, are the <$1000 'emergency' generators producing a/c or d/c within the windings?
    from HONDAPOWEREQUIPMENT.com:
    How does the inverter work?

    Honda 's inverter technology takes the raw power produced by the generator and uses a special microprocessor to condition it through a multi-step process.

    First, the generator's alternator produces high voltage multiphase AC power. The AC power is then converted to DC. Finally the DC power is converted back to AC by the inverter. The inverter also smoothes and cleans the power to make it high quality. A special microprocessor controls the entire process, as well as the speed of the engine.

    Honda uses only high quality inverters in our generators, which produce stable, consistent power.

    The end result? Clean enough power to run even the most sensitive electronic equipment.
    ***
    I wonder what is 'high voltage' to Honda? [for me =>69kV, per IEEE].
    ***
    that site suggests sizing the generator with more than 2.5x the furnace blower wattage --
    my generator has a 120 volt ac 240 volt ac and a 12volt dc

  11. #24
    Join Date
    Feb 2003
    Location
    Huntsville,AL
    Posts
    4,125
    my question is what is the 'high' voltage out of the mulitphase generator which goes to the invertor?
    480?

    not the output of the whole unit.
    harvest rainwater,make SHADE,R75/50/30= roof/wall/floor, use HVAC mastic,caulk all wall seams!

  12. #25
    Join Date
    Jun 2007
    Location
    louisville ky
    Posts
    107
    i called the company that put my furnace in and ask about running it off of a generator. they said turn the main breaker off. use a 10 2 wire and put male ends on both ends. plug one end in the generator and plug the other end in the plug the refrigerator is plugged in to and the furnace will work. does that sound right?

  13. #26
    Join Date
    Jan 2009
    Location
    Central NJ
    Posts
    29
    Technically that could work if the refrigerator circuit is the same as the furnace. That said do yourself a favor and call a licensed , insured electrical contractor to hook you up with a 4-6 circuit transfer switch to plug your generator into. If you inadvertently turn on your main circuit breaker while the generator is running you risk severly injuring someone or possibly even killing them. A transformer will transform voltage in either direction so your utility transformer that transforms 13kV-240/120 will transform your 120v to 13kv.
    A lineman working on a downed power line he thinks is dead could be injured or killed because Joe homeowner didn't connect his generator properly. Another point that was referenced is most new electronic board furnaces need a good clean solid ground to function. Reversed single phase polarity will not make single phase motors run backwards. A single phase motor has to be internally wired to run a different rotation if it is capable of reversed rotation.

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