Like any generator application, you’ve got a series of variables that will affect what you want to do and what the generator can do.
Resistive heat, or heat strips, are an ideal load for a generator. Stable, simple, easy to balance, they’re no different than what is used to load test generators - resistive elements. I can’t speak to Kaleb’s heat pump setup, but mine has 10kW of heat strips. I’m guessing Kaleb’s and yours are probably larger? So that would dictate the base load for your generator, along with whatever loads in the house (lighting, etc.) you might want. The killer when it comes to sizing generators, especially for a home application, is motor loads. Single phase motors, such as AC compressors and furnace blowers, are notoriously inefficient and draw substantial amounts of power to start. That's why you might have a well pump that’s 3/4 HP and need a 5kW (or larger) generator just to start it. My four ton AC compressor takes a minimum of around 16kW to start it - but the running current is relatively low compared to starting current. Here’s another variable - your Winco can probably do a much better job at motor starting than your Generac. Why? Because that Wisconsin engine has a lot of mass in it - the Generac doesn’t. The mass of the engine components and flywheel provide inertia that keeps things turning when a load is applied, preventing the engine from slowing down significantly. As for your Lennox furnace needing “clean” power, you’re probably OK. Here’s why: It may be frequency sensitive - so as loads are turned on and off the generator speeds up and slows down slightly, and speed is what determines frequency. If it has a “window” that it can operate within, say, 58 Hz-62Hz, you might be OK until a large load hits it and the speed drops off enough to take it out of that window. It might also be sensitive to the waveform that is produced by the generator. A generator won’t produce a clean sine wave, no matter how good it is. It will be “lumpy” and “lean” in one direction or the other for a number of reasons. However, I’m betting it probably would work, the Lennox folks are just being picky and covering their bottoms. Utility power is an average value over a given time - that is, depending on the time of day, loads on the system and the distance from the generating plant, the waveform and frequency of your power varies, too. Have you attempted to run the furnace off of one of your generators? I’m betting the Winco would do it without a hitch. -D > On Feb 16, 2021, at 6:34 PM, Randy Bennell via Mercedes > <mercedes@okiebenz.com> wrote: > > Dan and Jim appear to be the experts so I will sort of address this to them, > but anyone else that knows should pitch in too. > > My understanding is that one needs a whopper of a generator to power up > electric heat. Not only big enough but tough enough to run for long periods > of time at high load. > > So, how well would it work for someone like Kaleb and his heat pump? If it is > cold enough to need his electric elements as well as power his heat pump, how > much generator would he need. > > The other thing I am wondering about is what sort of generator one needs. I > have acquired a couple generators - a Generac that is rated at something like > 7500W and an older Winco powered by a 2 cylinder Wisconsin motor on propane > or natural gas - 10KW on propane but only about 8KW on natural gas. > > My concern is that I am told that my newer Lennox gas furnace wants clean > power and neither of my generators is capable of providing it. Should I look > for another in the form of an inverter generator or are they even likely to > produce power clean enough to satisfy the furnace? My other thought is > whether an inverter could be powered by one of my existing generators and > produce a clean sine wave power that would be capable of powering my furnace. > > Randy > > > _______________________________________ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
