The Engine Driven Generator for Home Power Alan Trautman The choice of an engine driven generator, or generator as I will refer to it here, is one of the most important choices those considering alternative power can make. You might say to yourself, "I have chosen wind, water or photovoltaics as my alternative power source. What do I need a generator for?" Well, that's what we are here to talk about. The generator has been the backbone of home power generation since the early 1900's. Many farms, ranches, and homes were modernized by the addition of only electric lights. In this day and age of public power, it is hard to imagine not having power lines to every house, everywhere. But in reality, the public power grid has only reached consumers in rural areas over the past 40 years or thereabouts. Many homesteads are still beyond the power grid even today. In the past, the most common way to have these modern electric lights was to use a generator. Early generators were crude by our standards but, never the less, they moved many rural families into the 20th century with electricity. During the 1920's many people living in the mid-West asked, "Why can't we use the wind to create our electricity? After all, the wind has been pumping our water for years." The wind did, and still does, generate electricity for these people. The U.S. government created the REA or Rural Electrification Act just for this purpose. This government plan helped to subsidize the wind power industry and to finance these wind/motor generator systems for the end users. Along with these windmills came the generator. That's right, generators were used along with windmills. The generator was used on days the wind didn't blow enough and the batteries needed recharging. Energy produced by either the windmill or the generator was stored in batteries. The batteries provided a constant source of power, where a windmill or generator could only supply an intermittent source of power. They needed the generator to back up the windmill. This brings us to one of the prime reasons for needing a generator for your home power system. Backup electricity. Let's say your choice of alternative power involves wind, PVs, or water. All these sources depend on Mama Nature doing her thing, and sometimes she doesn't. If for instance your windmill, solar panels or water generator cannot temporarily meet the demand on your system, you can use a generator to make up the difference. The generator allows the alternative source to be sized for average consumption rather that peak consumption. It also reduces the need to oversize the alternative energy source so that the system will recover quickly from periods of no alternative power input. This saves money and provides a second, backup, energy source to boot. Most people want their home power system to meet all their needs without the temporary inconvenience of too little power for peak consumption periods. The generator meets this need in the most cost effective manner. It can be wired into your battery-inverter system so it senses the increased load, starts itself, and carries the increased load until it is removed. The only way to handle this problem without a generator is to increase the size of your alternative energy source, battery pack and inverter. This latter decision will cost more. In many cases, you still wouldn't have the luxury of a back-up electrical system. Another reason for using generators in home power systems is to provide energy for battery equalization. During the use of a battery/inverter system, there is often the need to equalize the battery's individual cells. Equalization is a steady, controlled, overcharge of the batteries. The controllable and constant power output of the generator is ideal for battery equalization. In this instance, the generator will help pay for itself due to increased battery life, and greater system efficiency. At some time, any system that uses wind, water, and even solar will need to be shut down for maintenance. Wind mills periodically need gear oil levels checked, load brushes on the pivot serviced, propeller maintenance, and general nut/bolt tightening. Water power systems need periodic inspection of impellers, generators, water nozzels, and trash racks. Solar systems are virtually maintenance free, but even these require washing and the occasional rewiring job. The generator gives us a low cost, high powered, energy source to backup any other alternative energy source. The world we live in is as unpredictable as a child in a candy store. Natural disasters can flatten windmills with high winds. Ice can clog waterways and stop windmills as well as blanket solar panels. Lightning can do damage to any power source, including the public power grid. With your trusty generator providing a ready source of electricity, any household can be powered to suit your family's needs. If your main power system is the public utility, you just added independence to your household with a generator. You won't have to worry about when the power will come back on. You simply start your generator, and flip the load switch that has been installed between the power line and circuit breaker panel (for safety). Life goes on as you are accustomed. If you a considering home generated electrical power because of your remote building site, a generator can be useful from the initial ground breaking to the finished house. Power tools that are needed in the construction process can be run off of the generator. When the building is finished the generator is then used as your backup power source, practical and initially cost effective. What if, after considering all the available sources of alternative electrical power, you decide a generator should be you main source of electricity? Well, your decision isn't all that radical from a practical aspect. It is probably the most chosen source of alternative electricity today. Generators offer high power for a minimal initial investment. Generators come in many sizes and shapes to suit the consumer's many varying needs. In future issues of this column we will discuss all available types and sizes of generators. I want to aid you in selecting the one that best fits your needs and is most cost effective. Which generator will meet your needs? Well, the first consideration is the amount of electricity the generator will produce. The size or output of a generator is measured in watts. The number of watts you will need depends on the number of appliances you will be using and the energy consumption (in watts) of these appliances. By adding the appliances' ratings in watts, you can determine the size of generator needed. Give careful consideration to appliances which are selected for generator power. Appliance efficiency really counts when you are making your own electricity. Most people who are considering a generator, or any form of alternative electricity, try to stay away from electric heating devices. Electric heat uses lots of energy. Heating chores can be better handled by propane or wood fuel in rural situations. In addition to the running wattage rating of the generator, also consider its surge rating. The surge rating determines how much the generator can be temporarily overloaded and for how long. This factor is critical in determining the size of electric motor that can be started by the generator. Well pumps, refrigerators, washing machines, and capacitor started electric motors typically take up to three times their rated watts to start them. Some types of electric motors can consume over seven times their rated wattage during startup periods. This considerable amount of extra energy will make a larger generator necessary in some cases. It is a good idea to purchase your generator with more capacity than you actually need. This does two things. One, it insures that the generator is not working too hard-- greatly increasing generator life. Two, it allows for the inevitable expansion of your system. Another consideration in generator selection is the speed, measured in RPM (revolutions per minute), at which the generator operates. The 3,600 RPM generators are usually lighter duty than their 1,800 RPM counterparts. This is not always true, but in most cases this does apply. Smaller engines develop their power at the higher RPM. For this reason, they can be made smaller in size and lighter in weight. These small generators are typically air-cooled. The RPM at which an engine runs determines its overall life expectancy. Higher speeds wear the engine's moving parts more quickly, and thus the engine has a shorter life expectancy. The less expensive air cooled small engines will run for between 500 and 2,000 hours before major overhaul. Better made (and more expensive) small engines, such as those made by Honda, will run over 5,000 hours without major maintenance. The greater longevity of the better made engines makes them very much more cost effective. The speed of the generator also determines the amount of noise the generator will produce. The slower it runs the quieter it will be. Noise is an important factor in making the decision on which generator to buy. GET A GOOD MUFFLER! It is more than worth the few extra bucks it costs. A noisy generator will not only bother you, but it potentially will cause problems with any neighbors you may have. When you buy a generator, consider how you will start it. Many small generators are started by hand (recoil rope) only. The larger generators usually are electric (battery) start with a recoil starter as backup. The electric start generators can usually be operated by any member of the family, whereas hand started generators require the strength of an adult to turn them over. A last thought about generators would be about safety. Safety for you and for the generator. Personal safety for the operator is an important consideration many manufacturers take seriously. Some generators (usually cheaper models) don't have muffler guards and simple one knob operating controls. Imagine stopping the generator, like a lawn mower, by pressing the metal bar over the spark plug. Have you ever been shocked by this method? Most medium priced generators have operator safety as top priority. They have automatic chokes, belt guards, circuit breakers instead of fuses, and adequate muffler guards to prevent burns. These medium priced generators also protect themselves if they are somewhat neglected. They have fuel filters, automatic low oil level shut down, automatic overtemperature shut down, and exhaust spark arrestor screens in their mufflers. These items should be included in any generator used in home power service. Well, there you have it, a few ideas to stimulate more informed decisions about a generator use in home power systems. In the coming months we will discuss many specific types of generators, complete with our own test reports. We are looking forward to bringing you information on generator selection, maintenance, utilization, and longevity. I wish to emphasize that all this information is based on actual experience in the field, and is not a parroting of manufacturer's claims. I am looking forward to hearing from you generator users out there. Drop me a line and tell me about your system and experiences. Alan Trautman is a professional mechanic living on his rural homestead in Oregon. He has been making all his own electricity, and using mechanical generators since 1974.