Advanced Power Systems

Q. How large a generator do I need for my home or small business?

A. Every home or small business is different. The size of the generator is based on the type of appliances, equipment, pumps, air-conditioners, and other electrical devices requiring power and your preferred level of comfort. There are some power requirements that will establish a minimum size generator system: 

1) Well pumps usually require 2-3 times the run watts to start the pump. The Franklin Well Pump Company has an informative generator motor starting guide on their website that shows how large a generator kw rating you need for each horsepower pump. The charts are typically designed for three-phase applications with a note to increase the generator size by a certain percentage for 2-wire or single-phase applications. These charts are based on providing a safety factor for the pumps to reduce any voltage drop during startup of the pump motor to prevent heating and premature failure; 

2) Combination heat pump/air-conditioner systems are normally on 60 amp 240v (14400 watts) breakers and use 30 amps (7200 watts) for the heat cycle and the same for the air-conditioning function; 

3) Electric furnaces are typically on 50 amp 240v (12000 watts) breakers; 

4) Hot water heaters operating on 240v power normally use between 20 amps (4500 watts) and 25 amps (6000 watts) depending on the size and efficiency design; 

5) Electric kitchen stoves with oven and top burners are usually on 50 amp (12000 watts) breakers. Combination stoves with a separate top burner are on 30A breakers and the companion oven is on a 30A breaker; and 

6) Air-conditioners come in a variety of sizes and ratings. They need to be calculated based on the BTU output or stated amperage requirements. A general rule of thumb is 4kw for every ton (12000 BTU's) of air-conditioning. Some of the newer high efficiency pump-motors use a bit less. A 2-ton unit is rated at 24000 BTU's and normally will require 18- 20 amps (4300 - 4800 watts) to start the unit and 15 amps (3600 watts) to operate it.

Another factor you must consider is the type of voltage and the impact on available amperage. Your service panel is normally rated at 200 amps @ 240v and the average home uses approximately 140 to 160 amps of 240v power to operate everything at the same time. This 240v power enters your panel as two 120v lines with a neutral so you have both 120v and 240v power available. A single-phase generator system provides the same type of power.

7) The best approach is to calculate voltage and amps and determine the required watts. Your larger appliances (well pump, kitchen stove, water heater, electric dryer, electric heater, and heat pump system) will typically use 240v power and the lights and other smaller appliances will use 120v power.  It is important to consider this difference in doing the load calculations because the important calculation is to determine just how many amps and watts you will need.

For example, if you want to operate your refrigerator (20 amps x 120v = 2400 watts to start), freezer (20 amps x 120v = 2400 watts to start), electric hot water heater (20 amps x 240v = 4800 watts), washer (20 amps x 120v = 2400 watts), and electric dryer (30 amps x 240v = 7200 watts) all at the same time you will need approximately 19200 watts to meet the breaker requirements for these appliances. In reality the circuits and breakers are typically oversized for safety by 15% to 20% and the above appliances will not all operate at peak at the same time so the above load can be handled with a 15,000 watt (15kw) generator set (genset).

The major appliances, pumps, or other motor driven devices that you plan to power with your generator system need to be considered when calculating the minimum size of a generator. Sizing a generator system requires you to honestly assess your electrical power needs and wants when the utility power goes off.

Q. What kind of generator should I purchase - gaseous or diesel?

A. There are a number of factors to consider in evaluating the differences between a gaseous (natural gas or propane) and diesel powered genset: 

Gaseous powered engines can be summarized as follows for Positive Factors: 

1) Quieter engine noise level; 

2) Lower emission output; 

3) More convenient fuel source (natural gas); 

4) Gaseous engines do not have a problem with "wet stacking” like diesels;

5) Less expensive units with air-cooled engines are budget priced. 

There are also some negative LP and NG factors to consider: 

1) More expensive to operate by as much as 3-times the fuel consumption compared to diesels; 

2) Shorter life expectancy by a factor of 10 to 1 for air-cooled models and 3 to 1 for water-cooled models compared to diesel powered gensets; 

3) More expensive to purchase for models over 30kw; 

4) Smaller air-cooled gaseous engines are less expensive than comparable diesels but have a short life expectancy as low as 500-hours depending on engine make and use; 

5) Natural gas (NG) begins to de-rate at +20 degrees above zero and propane begins to de-rate around -20 degrees below zero; 

6) High winds and severe weather can disrupt the flow of natural gas lines with up-rooted trees; and

7) Both NG and propane can become very dangerous if lines are broken and gas discharges.

Diesel engines have a number of Positive Factors: 

1) Engine life for liquid-cooled 1800rpm engines can approach 20,000 hours if properly serviced depending on the application and environment compared to 5-6000 hours on industrial quality water-cooled engine gaseous gensets; 

2) Even 3600rpm diesel engines normally have a 10,000 to 12,000 hour life expectancy with proper maintenance and service under most conditions; 

3) Diesel engines are less expensive to operate. The general rule of thumb for fuel consumption is 7% of the rated generator output (Example: 20kw x 7% = 1.4 gallon per hour at full load). Diesel generators are designed for off-road applications and can operate on dyed or farm-construction diesel fuel which is sold without the road tax and thus is considerably cheaper to purchase;

4) Diesel engines are designed to work under a load for long periods of time and perform better when worked rather than operated under light loads;

5) Diesel engines can operate in very cold conditions with fuel additive;

6) Diesel engines and fuel are safer to operate because of the high flash point of diesel fuel - it is even difficult to start a fire with diesel fuel; 

7) Diesel fuel is easier to obtain during a disaster because it is a necessary fuel for the military, trucking industry, and farming operations; 

8) Diesel gensets are competitively priced for a comparative sized water-cooled gaseous models with the same features; and 

9) The cost of owning a diesel generator system where usage is high is much lower over the long run than gaseous gensets. 

Negative Factors to consider with diesel engines: 

1) Engine noise is usually higher on a diesel compared to a gaseous engine. The use of a properly designed enclosure and sound attenuation system is more critical on a diesel engine system; 

2) A diesel engine is subject to "wet stacking" or over fueling if run for long periods of time with ultra light loads (less than 40% of the rated output). "Wet Stacking" causes the engine to smoke and run rough because the injectors become carbonized. Running a heavy load will usually clean up the over-fuel condition and allow the engine to perform properly. Diesel engines operate better and more fuel efficient when loaded (70-80% of the rated output is optimum); 

3) In sensitive emission areas in some states diesel engines are prohibited from operating over a prescribed number of hours per year to help reduce pollution levels; 

4) Diesel engines require clean moisture free fuel and a bit more maintenance than a comparable gaseous unit; 

5) Diesel fuel storage must be considered relative to required run time in your geographical area. If you live in a severe weather area or are off-grid and use generator power as your utility you might need a large fuel tank due to the possibility of extended generator power usage. Some cities and counties require the generator on-board fuel tanks to be double-wall containment type, which can increase the cost of the generator system. Normally, a trailer mounted generator is exempt from these fuel tank requirements. You need to check with your local planning department for these requirements; 

6) Diesel gensets are typically heavier and require more planning to load and unload than a lightweight gaseous genset; and 

7) A quality diesel genset can cost considerably more than an inexpensive air-cooled gaseous light duty standby genset of the same size. APS recommends the use of liquid-cooled diesel engine gensets in severe weather environments where the potential for long run times is high or for prime duty applications where the generator is the prime source of power. APS carries a number of high quality diesel powered generator products for residential, construction, and industrial applications in sizes 3kw to 2000kw designed to provide years of trouble-free operation. We supply all the major brands and most of the high quality import brands.

Q. What is the difference between a UL2200 rated generator system and a non-UL2200 generator system UL2200?

A. The majority of electrical components used in power generators manufactured in the USA are UL listed or rated. Breakers, switches, motors, wire, and even the generator system are almost always UL rated and carry the UL logo. There are some imports and even some small generator packagers who have utilized some non-UL listed components for gensets or ATS panels being exported. Some of these gensets have apparently made there way into some USA markets. To help reduce this potential problem UL Laboratories has promulgated a new generator system rating (UL2200) which some States, Counties, and Cities have adopted. This new UL rating requires that the generator system as a unit, not just the components, be UL tested and rated. The net effect is that a majority of UL2200 rated generators are the same as before the UL2200 requirement with few exception but are more expensive because of the testing for each different size and model by UL Labs.

Many of the imported units and gensets manufactured by smaller packagers that offer a real value in genset cost and quality are not yet UL2200 rated because of the high cost to do so (each model genset needs to be UL tested) It is safe to say UL2200 has increased the cost of gensets. As would be expected the larger name brand US manufactured gensets from Cummins, CAT, Kohler, Generac, Katolight, and a few others are available in UL2200 models. Some of the other major high quality import brands like Broadcrown, Pramac, and Listter-Petter offer UL2200 models on a special order basis at a higher cost. The net effect of the law has been to increase the cost and reduce the competition. Fortunately, many City and State planning departments have not yet adopted the UL2200 standard which in many cases allows you to pay more for just a few safety stickers. It is normally the State electrical inspection function that regulates whether or not generators need to be UL2200 rated. It is always a good idea to check with the County Planning function to see if they have a generator installation guide and regulation. Check to see if UL2200 is required.

Q. There are a lot of Asian manufactured low-priced generators advertised on ebay and marketed through various discounters – are they a bargain?

A. APS advises caution when it comes to the low priced imports from Asia. In recent years there has been a flood of Asian manufactured gasoline and diesel portable generators using look-alike Honda-type gasoline and Yanmar-type diesel engines packaged in a wide variety of product designs. These units are typically considerably less expensive than the real Honda gasoline generators and the real Yanmar, Hatz, or Kubota diesel engine powered generator systems like the ones APS offers for sale. The old adage of "you get what you pay for" has never been more true than when dealing with these imported Asian generator systems. While the initial cost is low and the products are attractively packaged there are some things you should consider before you purchase one:

1) While the engine on some models tend to run ok and under light operating conditions last for a while, they tend not to do so well in high heat or heavy use environments.

2) The generator ends tend to be more problematic than the engines. Our experience has been they do not hold up for high use applications especially in hot weather.

3. There is very little support for these units and most generator and engine repair centers will not even consider working on them. Other than the company who sold you the portable gasoline or diesel generator or generator-welder you will find few repair centers that will give you the time of day. 

4. We base our observations on our own experience with these inexpensive Chinese imports and the related warranty problems. Our policy of honoring our warranty commitments to customers proved an expensive lesson. We have received many calls from frustrated customers who saved a buck but paid a price. One fellow called us from the Bahamas, who had operated a 6kw diesel import for a total of 4-hours before it failed and wanted to know if parts were available. He concluded that he had thrown away $1800 thinking he had gotten a bargain. 

5. There are some importers who advertise these low cost Asian engines and generator systems with Mercedes or Mann type engine designs indicating they are industrial grade and advanced designs. In truth many of these engine or generator products are 1930's vintage designs and great if you love to spend all your time working on them. There is absolutely no comparison in quality or performance between these low cost engine or generator products and the modern Japanese or European products.

Again, you get what you pay for and saving a few bucks on a cheap engine or generator system will likely cost you money.  If your application is for occasional real light use in a cooler climate you may have some limited success using the cheap imports. Again, you normally get what you pay for and the other old adage, "if it appears to be to good to be true, it most likely is", is so true in the purchase of these cheap imports.

Q. Are any of the Chinese generator imports considered high quality?

A. Yes. Some of the more industrial quality Cummins, Deutz, John Deere, and MTU diesel generator systems seem to be of much higher quality design and feature better components. A majority of these products are designed for 3rd world and non-EPA regulated countries. Are these products of the same quality as those made in USA and European imports? It is too early to know. As for service and parts support, that most likely is another issue and related to the importer of the product in each geographical area or country.  

Q. Is a 3-phase generator end suitable for the average homeowner or small business using single-phase power?

A. A majority of generator packagers typically will use an over-sized 12-wire 3-phase 3-pole generator end for single-phase applications and utilize 2-poles for single-phase. This requires that the generator end is sized approximately 1/3rd larger than the rated single-phase output. This approach of using a 12-lead over-sized 3-phase generator system allows the generator system to be used for both single-phase and 3-phase applications depending on customer requirements. (Example: 10kw engine coupled to a 15kw generator end). There are a number of major brand products that are packaged with dedicated 4-lead single-phase only generators. For the most part these are quality products designed for a specific single-phase application. 

A note of caution: Generator packagers who assemble a 10kw engine & 10kw 3-phase generator end and utilize this configuration for single-phase applications are selling you a potentially problematic generator configuration because the engine will always be oversized for the single-phase output capability and running light loads will make the engine susceptible to "wet stacking".  

APS uses a wide variety of the leading generator ends for both our single-phase and 3-phase applications (Newage/UK & USA, Somers/France, Mecc Alte/Italy, and Marathon/China & USA). The advantage of using an over-sized generator in a 3-phase or single-phase application is to meet motor starting requirements without having to use an overly large diesel engine because of potential problems with "wet stacking". If your generator system will power air-conditioning units, pumps, heat pumps, well pumps, welders, or irrigation pumps you need to have the system calculated by one of our sales engineers to make sure of the proper design and size. APS provides this service free. Proper generator sizing is critical in the generator selection process. APS pre-sets the proper voltage configuration and performs a load test on all of our gensets at the factory before shipment.

Q. What is the function of the electronic controller on a genset?

A. Most of the engine/generator controllers used today are digital and are designed to provide control of the engine and generator safeties and any auto-start function for automatic transfer switch or inverter applications. The controller system, simply described, establishes the bench mark or threshold for safety shutdowns and monitors the operation of the engine and generator functions. The sophistication of a controller is based on the size of the generator and the application. Most modern digital controllers for residential or small business applications are typically a simplified LED indicator for any shutdowns and a start-stop button or auto-start function. These digital controllers are much more efficient and cost effective that the simple key-start and gauges typical on older products.

In the auto-start mode the controller can be used to interface with an automatic transfer switch or inverter/battery system as a standby/emergency genset. A more advanced controller provides real time monitoring of volts, hertz, and amperage in addition to the basic engine/generator safeties and auto-start functions. Complex controllers typically installed on larger generator systems provide engine safeties and shutdowns for low oil pressure, high temperature, engine start over-crank, over/under-speed (hertz), low coolant level, low fuel level, KVA output, KW output, power factor (PF), engine & generator gauges in real time, and often have a communication capability for remote monitoring and starting. APS uses a number of different digital controllers on our gensets depending on the application and customer requirements. All of our generator controllers are off-the-shelf, state-of-the-art design, for long life service and availability. We provide a single-source contact for parts for all of our products now and in the future.

Q. Do 3600rpm diesel generators last as long as 1800rpm gensets?

A. Generally the 1800rpm engine speed will last longer, use less fuel, and are slightly quieter than the 3600rpm units. Most small diesel portable generators in the 3 to 6kw class are air-cooled 3600rpm engines designed to keep the weight and cost down. APS has designed a 3600rpm air-oil cooled Kubota diesel powered portable for severe duty applications that has an expected engine life of up to 9,000 hours. This unit has been engineered to provide reliable power for construction, military, rental industry, and government applications. Our 3.5kw liquid-cooled portable generator systems are rated for 10,000 to 15,000 hour service for a wide variety of battery charging, remote site pumps, RV and other mobile use, and a number of other critical function applications.

Kubota has developed the GL7000 / 7kw and GL11000 / 10kw series quiet enclosed contractor-residential rated gensets using liquid-cooled 3600rpm engines to keep the weight and price affordable with great success. These engines are designed for long-life performance up to 12,000+ hours depending on environment, use, application, and maintenance. APS has units operating in some of the most severe environments in the world with good results. APS has developed several proprietary options for these gensets: 1) Digital controller with auto-start for ATS panels and inverter applications; 2) Remote fuel system for use with 55-gallon drum and other larger fuel tanks; 3) 4-wheel kit with brakes; and 5) compact trailer for contractors and other mobile applications. Kubota offers a remote start kit with a 96’ cord and Key start-stop panel.

APS carries the full line of Kubota industrial engines, generators, and related parts. We offer discount pricing on these quality products around the world.

Q. We want the power generator to supply power to a computer system in our home or business - will we need a special generator design?

A. Most generators sold by APS are designed to power computers. Some of the portable generators with capacitor regulation (voltage control from 5% to 10%) can present a problem for some computer systems if the computer is plugged directly into the electrical circuit and does not use a battery regulated power supply. The majority of 1800rpm and 3600rpm liquid-cooled generators use automatic voltage regulated (AVR-Electronic module) generator systems that provide from 1% to 2% voltage regulation. Another factor that impacts computers is the speed (hertz) control which is normally 3-5% with a mechanical engine governor system and .25% to .5% regulation with an electronic engine governor system. The mechanical governed systems are normally quite sufficient to provide clean power for normal electronics like computers, stereo systems, etc.

For computer service centers and other communication applications like radio stations and relay centers even if they use a UPS system the use of an electronic governor on the diesel engine is recommended. Electronic governors not only maintain engine speed more accurately but provide a much quicker response time to no-load to load conditions which helps prevent voltage drop. Most industrial diesel engines equipped with auto-start can be equipped from the factory with an electronic governor depending on the manufacture and engine design.

Q. What is the difference between standby and prime duty?

A. Standby or emergency service is defined as usage during emergency power outages for the duration of the outage not to exceed 500-hours per year. This rating assumes that the load will be varied and intermittent as it is under normal utility applications. Prime power is defined as regular power used on a daily basis normally 8-12 hours per day which will typically exceed 500-hours per year. Prime duty is typically 10% less than the standby rating. Continuous duty is defined as 24-7 operation and is computed as 5% less than the prime duty rating. In addition to the generator duty ratings there are de-rates for altitude, high heat, and humidity which must be considered when calculating proper generator output.

Q. What does the term "Wet Stacking" mean in a diesel engine?

A. Diesel engines are designed to operate with a load. When a diesel engine operates considerably below the rated output level the engine can start to over-fuel or "Wet Stack". Diesel engines perform most efficiently in the 70-80% range of rated output. When an engine operates for a prolonged period of time below 40% of the rated output it begins to over-fuel. This occurs because the injection tips began to carbonize and disrupt the fuel spray pattern. In commercial generator standby/emergency systems where loads can vary and low output conditions can occur more frequently because of the diverse load applications, an automatic load bank is sometimes used. A load bank will place a "false" load on the generator system to keep the diesel engine properly loaded to prevent a "Wet Stack" condition and automatically adjust the false load to the real load. 

In residential or small business applications a "false" anti-wet stack load condition can be accomplished with the use of an electric heater or other high load appliance to make sure the diesel engine generator system is not allowed to operate for prolonged periods of time below an acceptable level. Once a diesel engine begins to "wet stack" the only way to correct the problem is to load the engine for a couple of hours to burn off the excess fuel and clean up the engine. Some diesel engines are less prone to "wet stacking" than others. Generally, electronically controlled engines and engines with advanced emission systems are less likely to "wet stack". Unfortunately, all diesel engines will "wet stack" if operated for long periods of time considerably below the rated output level. It is for this reason that proper sizing and design is important. APS can help you with all your sizing and design considerations. It is part of our Sales Engineering Service program and it is free.

Q. What kind of maintenance will my diesel generator need and how complicated is it for the average homeowner or small business?

A. Diesel engines require routine maintenance for long-life service. The normal maintenance requirements are about the same as owning a diesel-powered vehicle - oil, oil filter, air filter, and fuel filter. In tropical and cold climates it is advisable to have a water-fuel separation filter system installed. Water or moisture in diesel fuel can be damaging to a diesel engine because the water properties create advanced ignition and accelerated detonation. The engine will need an oil change every 100 to 250 hours depending on the dust conditions where you live. We recommend you change the oil filter every time you change the oil. The filters are normally the screw on type. Air filters need to be changed as required depending on how much dust is in the air.

Diesels need a lot of clean air to operate properly and will suction collapse an air filter if it is allowed to get too dirty. We recommend you check the air filter every 100 hours and every 50 hours in dusty environments. Fuel filters are normally changed every 200 to 250 hours depending on how clean the fuel and dust conditions. Every diesel engine has a recommended service schedule. Like a diesel powered vehicle regular scheduled service is the key to long-life and performance. Normally, the generator end (AC alternator) will not require any service unless you live in a dusty environment. In dusty environments we recommend you use a high pressure (50psi) air hose and occasionally blow out the dust from the generator system. Dirt and heavy dust particles can cause shorts in the internal wiring coatings under the right conditions. High heat and dust are the enemy of power generator.

Q. Will the genset I purchase from APS have adequate operating instructions and service manuals?

A. Every genset sold by APS comes complete with an operators manual for the engine, generator, and controller if applicable. We include any special instructions for any of our added options or features (e.g. APS remote fuel system connection & switch). In addition, most of the manufactures offer factory service and parts manual kits as an option. APS, as part of our Customer Advantage Program supplies each generator system with an Easy-Start Guide with photos for wiring connections, other starting info where applicable, and lifetime technical trouble-shooting support via phone, fax, or e-mail to make it easier for customers to own an APS supplied genset. Our goal is to make owning an APS supplied generator system a trouble-free experience.

Q. How do transfer switches work and can I install one myself?

A. APS recommends that transfer switches be installed by a licensed electrician for safety reasons. A transfer switch should be considered an "either or switch" that allows power to be supplied to the service panel either from the utility or the generator system. There are basically four types of transfer switches to consider: 

1) Manually operated Meter connected switches designed to allow for a low cost and simple and inexpensive installation for generators supplying 7500watts or less; 

2) Manually operated Pre-select panels providing 6 to 10 pre-selected circuits that can be used during any generator supplied power situation; 

3) Manually operated Service rated (e.g. 100A, 200A, or 400A) NEMA-1(indoor rated) or NEMA-3R (outdoor rated) UL rated panels for either single or 3-phase applications; and 

4) Automatic operated Service rated panels. If you are using a small portable generator system and have light power requirements for lights, refrigerator, microwave, etc., the use of the Meter connecting transfer switches can be very cost effective and simple to use and install. You will need to check with your utility company to make sure they allow the use of this type of transfer switch and the approved installation procedure. APS can supply this type of residential transfer switch should you require one.The use of a manually operated Pre-select type of panel is also suitable for use with smaller generators. Many of these type of transfer switch will only allow 120v applications. Check specifications to make sure this type of panel will meet your power requirements. APS can supply this type of transfer switch in both single-phase and 3-phase models.

Service rated manually operated transfer switches allow you to match the size of the service panel (even if the generator is rated lower than the service panel) so you can power any circuit in the panel subject to the limits of the generator output (a 10kw generator is rated for 42Amps @ 240v single-phase and the normal service panel today is rated for 200Amps). This allows you to provide power to any breaker in the panel even though you may not be able to use them all at the same time based on your generator size and what you want to power. These panels normally require an electrician to install. Transfer switch panels are normally sized to match the service entrance panel unless there is an emergency panel installed or you are using one of the small limited output panels for portable generator applications.

This is the normal sequence of events when the power from the utility goes off: 

1) Manually switch the handle on the transfer switch to the generator position; 

2) Start the generator and allow it to properly warm up with the generator breaker in the off position; 

3) Once the generator engine is warmed up to operating temperature engage the main generator breaker to feed power to the service panel. 

When the power returns from the utility the sequence of events is reversed: 

1) Flip off the main breaker on the generator so there is no power to the service panel; 

2) Flip the manual transfer switch back to the utility feed position; and 

3) After the generator engine has run with no-load and cooled down for approximately 5-minutes shut the generator engine down. An automatic transfer switch (ATS) or inverter system with auto-start function is designed to work with the generator auto-start system which is usually a part of the generator controller system. The ATS panel is normally sized to match the service entrance panel amperage size or a special emergency panel (E-panel) created to operate special circuits that are needed during any power outage. The ATS operates with digital logic and a motorized breaker system. To activate the ATS system a two-wire open or closed low-voltage contact system is used and connected to the auto-start function on the generator controller. 

The sequence of events is much that same as the manual transfer switch but done automatically so the generator starts and stops based on utility or battery power supply

1) Utility power goes off or batteries are low and need a charge; 

2) Contacts in ATS panel either open or close (optional) creating an open or closed circuit in the generator controller; 

3) The generator controller circuitry starts the generator for a brief warm up (programmable); 

4) If the power stays off for a programmed period of time (usually2-minutes) then the ATS panel switches the power requirement to the generator side of the transfer switch and the generator becomes the power supplier; 

5) Once the ATS panel senses that the power has been restored from the utility it switches the breaker back to the utility supply side and disconnects the generator from the circuit; 

6) Normally, the ATS panel is programmed to disconnect the generator but let it continue to operate for approximately 5-minutes to cool down or to be ready to return in the event the power from the utility starts and then fails again; 

7) Finally, the generator is shutdown when the open or closed contacts return to the original position before the power outage. One advantage of using an automatic transfer switch in 3-phase applications is the in-phase monitoring system that prevents power transfers when the transfer will damage an out-of-phase electric motor. Another benefit is the automatic exerciser function that regularly starts and runs the generator to make sure it is operating properly and to provide a regular lubrication and system check to assure the unit is run-ready when it is needed - when the power from the utility fails or the inverter system senses the batteries are low and need a charge.

Q. How are warranties handled by APS?

A. APS tries to sell the highest quality products available and we use only the best off-the-shelf components in our own gensets to minimize any potential warranty problems. APS provides our customers with the factory warranty and terms & conditions on products we distribute. On APS private label or manufactured products we provide you with a 1-year warranty on the product components. The engine & generator warranty period is based on the manufactures warranty and terms and conditions, which may be longer.

We also provide you with a single-source contact for any parts or warranty requirement. Normally, it is the customers responsibility to get the product back to the manufacturers warranty station or factory for any warranty support. APS will try and make arrangements for any warranty to be performed by any competent generator or engine repair facility near the customer’s residence or business. The quality of most generator products today is very high. The occasional problem can usually be resolved with a little trouble-shooting and minor repair and this can often be done over the phone. APS provides free product lifetime technical trouble-shooting service to the original purchaser via phone, fax, or e-mail. This valuable service is only available through APS.

Q. What is the difference between standby/emergency use and prime or prime continuous duty applications?

A. A majority of generator products are rated for standby or emergency use. This designation is for generators that will be used less than 500 hours per year and typically for short periods of time when the utility power fails. The prime duty rating is for use when the number of hours per year will exceed 500 and the use is on a regular basis. Prime continuous duty is the rating given for generators that are used 24-hour per day and 7-days per week. These ratings are based on the fact that the generator system will perform at the highest standby rating but when the hours or use exceed the recommended standard for standby the life expectancy can be shortened considerably and the potential for premature failure is increased. It is for this reason that the proper assessment of the application should be declared at the time of purchase. Buying a genset rated for standby duty and using it for prime or prime continuous application is penny wise and pound foolish and will normally void your warranty and cause you premature generator failure. Your generator system should be a long-term investment if properly sized and designed for your application.

Q. Why do well pumps, air-conditioners, welders, and other electrical motor driven appliances require special consideration when sizing a generator?    

A. In general, appliances with electric motors have a much higher start up amperage (LRA) requirement than operating amperage (FLA). A general rule of thumb is a minimum of at least twice the amperage to start a device as to run it. However, some devices can require up to 6 or 7 times the amperage to start as to run. It is for this reason that any residence or business with water wells, large air-conditioners, sump-pumps, or other heavy duty motor applications should consult with a knowledgeable source when sizing a generator system. APS can assist you with all of your motor starting calculations and we can supply you with generator systems designed to provide the best performance and size for heavy-duty motor starting applications.

Q. How are decibel levels calculated on generators?

A. Most generator builders calculate dBA levels at full load operation. This is the honest way to report the noise level. The USA standard is based on the sound level at 21-feet and the European standard is based on the sound level at 23-feet. The calculation of dBA levels involves a complicated mathematical formula which is not the subject of this information. The relative noise level is the best way to understand the relationship of one sound to another. Generator sound levels can best be compared for small to medium generator systems (7kw - 60kw) as it relates to human conversation while a diesel genset is operating at full load;

*Entertainment Industry Quiet / Special and expensive sound attenuated and designed gensets 50 to 55 dBA - barely hear the unit operate at 3-feet / normal conversation next to genset; 

*Ultra Quiet / special sound attenuation design for rental fleets or residential applications56 to 60 dBA - barely hear the unit operate at 10-feet / normal conversation at 10-feet;

*Super Quiet / special sound attenuation enclosure normally with air-scoops and dense foam61 to 63 dBA - normal conversation at 10-feet / quiet operation at 21-feet;

*Residential Quiet / well designed enclosure with air-scoops and foam  64 to 68 dBA - quiet but noticeable at 10-feet / normal conversation at 21-feet. For the average residential application dBA levels in the 64 to 68 range are acceptable to most neighbors and meet most noise level restrictions if any exist. Some engines tend to be noisier than other engines and will have some effect on the overall dBA rating of the unit. Obviously, a 10kw generator is typically quieter than a 40kw if all other conditions are equal.

*Industrial Quiet / well designed enclosure with air-scoop and dense foam69 to 75 dBA - noticeable noise level at 10-feet / loud conversation at 21-feet;

The abatement of noise in diesel gensets is normally a function of the enclosure design, air-flow, and the quality and type of insulation used. Front air-scoops are typically used to remove radiator sound. Special residential grade muffler systems are used to help reduce the engine noise. Barriers can be erected between the residence and the generator system to further reduce the sound level.

APS can supply you with all of the quiet type generator systems listed above. For special residential applications where covenants or city codes require Ultra quiet sound levels APS has developed special acoustically engineered enclosures to meet these requirements. The APS, Kohler, Lister-Petter, and SDMO residential and small business gensets are rated for Residential Quiet applications.

For industrial super quiet applications, such as those required for the movie industry, APS can supply special ultra quiet generators designed to operate in the 50-56 dBA range in both switchable stationary or mobile design, and stationary for industrial and residential high end applications where sound regulations or zone covenants place restrictions on sound levels.  

Q. What are the most important things to consider when purchasing a standby/emergency generator system?

A. This is the most frequently asked question. Our answer is several-fold: 

1) A generator is a major purchase and should be amortized over it's expected life depending on the use and environment where it will be used. For most residential applications a quality generator will last a lifetime if used for standby/emergency backup. For this reason we recommend the purchase of a quality genset with suitable features for your application. A cheap or bargain price is sometimes an expensive lesson; 

2) If your backup requirements are very occasional and you only need limited power during an outage an inexpensive generator system will most likely meet your needs (air-cooled gaseous gensets); 

3) If you live in any of the severe weather areas in the USA or Canada you are likely to need a heavy duty diesel genset and one with high quality features. Most modern diesel engines are reliable and fuel efficient. Glow plug models provide easy starting in cold weather. An 1800rpm model will provide better fuel efficiency and longer life but cost more; 

4) The generator end is the usually the first item to fail with heavy use. The insulation coatings on the windings are based on heat ratings and 'F' is good and 'H' is better. Some major brands manufacture their own generator ends and parts, and repair is usually only available through the manufacturer. APS uses off-the-shelf industrial brands like Marathon, Mecc Alte, Newage, and Somers because parts are readily available and any qualified service repair center can service the generator end; 

5) Controllers are a vital part of most generator systems. The controller monitors the generator engine speed for hertz, the oil pressure and water temperature, and other engine and generator functions. It shuts down the engine if one of the threshold settings for these controls fails. It also provides the auto-start function for the automatic transfer switch or inverter if one is used. APS uses off-the-shelf name brand controllers on our products to make sure they are available if one should fail; 

6) A generator is a mechanical and electrical device that over time will need some service or parts. Make sure you are purchasing a generator system that will be supported in the future from a company that will be there to support you; and finally,

7) know what you intend to operate with your generator and make sure the generator you purchase will handle your load. APS can help you with design considerations, load calculations, and motor starting considerations. In our opinion, these are the most important things you need to consider when purchasing a generator. 

Q. What is the advantage of buying a generator direct over the internet or phone through APS as opposed to buying from a local dealer?

A. APS supplies many of the best generator products available in the world today at the most competitive prices. Our factory direct program removes the middleman and generally saves the customer 10-20% off the normal dealer price. Another benefit is the wide selection of products and our knowledge of available products and specifications. This insures that you get the best generator system for your application at the best possible price. 

The APS Customer Advantage Program gives you protections and support that makes it easier to purchase and own a generator system: 

1) SALES ENGINEERING SERVICE - competent and knowledgeable sales engineers to discuss all your requirements and application and to properly help you size and calculate all motor starting requirements; 

2) CUSTOMER-FIRST - APS support for all parts and warranty assistance on all of our products; 

3) DESTINATION SHIPPING - for trouble-free shipping in the USA we ship FOB destination so we take care of any cargo claims for you; 

4) EASY-START GUIDE - Info & photos for generator electrical connections and controller operation;  

5) AFTER-SALE SUPPORT - free lifetime technical trouble-shooting support via phone, fax, or e-mail. We do our best to honor our commitment to providing you with the BEST PRODUCTS, BEST PRICES, and BEST SERVICE; and

6) FRIENDS REFERRAL PROGRAM - $100 referral fee to you for any of your friends that purchase from APS. Our business has been built on referrals and repeat customers. We treat our customers the way we would want to be treated – as friends.

Call and talk to one of our sales engineers for a generator consultation and assistance for sizing and motor starting applications. We are here to help.


Direct: 855-664-3599