Niel
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Joe:
You need to be concerned about input power not force. Power [1] is work per unit of time or Force x distance / unit of time.
Most small generators have operational efficiencies of between 93% and 97% [2]. As a result if you want to have a 5KW generator as a power station you should plan on providing that generator with at least 5.5KW of mechanical power though the input shaft. I am providing little bid of a safety margin here.
Niel
15 years ago
Source: [1] http://en.wikipedia.org/wiki/Power_(physics)
[2] http://www.jcmiras.net/jcm/item/93/
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Bob W
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Hello and thanks - While I am not in this line of business I was struck by the lack of answers and will hopefully guide you to a dealer in residential units with installation. I work in oil and gas and not generators so no tainted answer here. First google home generator safety and there are good articles.think Safety, Safety, Safety. Follow the National Electrcal Code. I say no homebrew equipment or homeowner intallation for safety reasons. The losses, imbalances, ground fault characteristics, etc can lead to heating and fires. Then there is the carbon monoxide potential and so correct outdoor location and indoor carbon monoxide sensors are a must. This does require transfer gear which is essential in a hard wired power source run through code required circuit breakers. The small 1800 watt unit has circuit breakers built into the unit along with the required grounding connection. One horsepower is 746 watts and then take if from there as to efficiency. An alternate is such as my home generator which is a Coleman at 1600 watts. It is placed at the edge of the patio well away from the house and powers a lamp and refrigerator using temporary wiring usually for 2 days. The argest "portable" unit install was on the company hazmat vehicle with a past company and it was around 8K watts and made by Onan. So how much do you want to run? The fan motor in the A/C may be 3/4hp and the compressor 3/4 hp. Google a table of load values for the home. From what I read this last summer during hurricane season people were paying $15000 for an 8K home stationary unit and switchgear. So 8K before efficiency losses at a rounded value of 750 watts per HP would be about 11 hp and with losses about 15hp. A google of generators shows 7.5K watts with a 15hp motor so I think the physics is on target.. Again think Safety and use a commercially designed and installed system.
15 years ago
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Niel
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Bob:
I am not sure that you or I have answered the original question, but you have supplied a lot of information concerning sizing a generator of domestic applications.
Thank you - Niel
15 years ago
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Joe
ASKED BY
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To Neil & Bob,
Thank you so very much for you time, knowledge and answers to my question. You both supplied me with the info I needed to find the answer I was looking for. It's a pleasure to have this opportunity to participate in a fourm such as this were there are so many very intelligent people willing to help with any question.
So, thank you both very much and yes, my question was answered completely.
Joe
15 years ago
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