FAQS
 Industrial Generator FAQ 
(Frequently Asked Questions)
http://www.dieselserviceandsupply.com/admin/images/man_thinking.jpgMany of our customers rely upon us to provide them with accurate and informative answers to their electrical, engine, generator and controller related questions. Some of which are quite common and we answer quite frequently.  In order to better inform our customers and website visitors alike on some of the most popular topics and issues we encounter, we have decided to begin a list of Frequently Asked Questions.  We plan to expand uponthis section over time and add any other commonly asked question that we encounter.  If you have any additional questions you would like to see showcased here please email us with your suggestions and we will do our best to answer and incorporate them here.
1. What is the difference between kW and kVa?
2. What is a power factor?
3. What is the difference between standby, continuous, and prime power ratings?
4. If I am interested in a generator that is not the voltage I need, can the voltage be changed?
5. What does an Automatic Transfer Switch do?
6. Can a generator I am looking at parallel with one I already own?
7. Can you convert a 50 Hz generator to 60 Hz?
8. How do I determine what size Generator I need?
9     What is the process I will have to go through to get a generator installed and ready for back-up?
10    What should I consider when choosing a generator?
11    How much outdoor space do I need for the generator?
12    Is there someone that can help me decide what generator I need?
13    What is included with the generator?
14    Will there be any other costs that I might incur?
15    How long does a generator take to install?
16    Does a generator need maintenance?
17    What is the difference between running watts and starting watts?
18    How can I determine the running or the starting watt requirement for a tool or appliance?

What is the difference between kW and kVa?
The primary difference between kW (kilowatt) and kVA (kilovolt-ampere) is the power factor.  kW is the unit of real power and kVA is a unit of apparent power (or real power plus re-active power).  The power factor, unless it is defined and known, is therefore an approximate value (typically 0.8), and the kVA value will always be higher than the value for kW.  
In relation to industrial and commercial generators, kW is most commonly used when referring to generators in the United States, and a few other countries that use 60 Hz, while the majority of the rest of the world typically uses kVa as the primary value when referencing generator sets.
To expand on it a bit more, the kW rating is essentially the resulting power output a generator can supply based on the horsepower of an engine.  kW is figured by the horsepower rating of the engine times .746.  For example if you have a 500 horsepower engine it has a kW rating of 373. The kilovolt-amperes (kVa) are the generator end capacity.  Generator sets are usually shown with both ratings.  To determine the kW and kVa ratio the formula below is used.
0.8 (pf) x 625 (kVa) = 500 kW
What is a power factor?
The power factor (pf) is typically defined as the ratio between kilowatts (kW) and kilovolt amps (kVa) that is drawn from an electrical load, as was discussed in the question above in more detail.  It is determined by the generators connected load.  The pf on the nameplate of a generator relates the kVa to the kW rating (see formula above). Generators with higher power factors more efficiently transfer energy to the connected load, while generators with a lower power factor are not as efficient and result in increased power costs.  The standard power factor for a three phase generator is .8. 
What is the difference between standby, continuous, and prime power ratings?
Standby power generators are most often used in emergency situations, such as during a power outage.  It is ideal for applications that have another reliable continuous power source like utility power.  It’s recommend usage is most often only for the duration of a power outage and regular testing and maintenance.
Prime power ratings can be defined as having an “unlimited run time”, or essentially a generator that will be used as a primary power source and not just for standby or backup power.  A prime power rated generator can supply power in a situation where there is no utility source, as is often the case in industrial applications like mining or oil & gas operations located in remote areas where the grid is not accessible.   
Continuous power is similar to prime power but has a base load rating.   It can supply power continuously to a constant load, but does not have the ability to handle overload conditions or work as well with variable loads.  The main difference between a prime and continuous rating is that prime power gensets are set to have maximum power available at a variable load for an unlimited number of hours, and they generally include a 10% or so overload capability for short durations.

If I am interested in a generator that is not the voltage I need, can the voltage be changed?
Generator ends are designed to be either reconnectable or non-reconnectable.  If a generator is listed as reconnectable the voltage can be changed, consequently if it is non-reconnectable the voltage is not changeable.  12-lead reconnectable generator ends can be changed between three and single phase voltages; however, keep in mind that a voltage change from three phase to single phase will decrease the power out put of the machine.  10 lead reconnectable can converted to three phase voltages but not single phase.  For more information, here’s a useful pdf file from the U.S. Army Corps of Engineers.

What does an Automatic Transfer Switch do?
An automatic transfer switch (ATS) transfers power from a standard source, like utility, to emergency power, such as a generator, when the standard source fails. An ATS senses the power interruption on the line and in turn signals the engine panel to start.  When the standard source is restored to normal power the ATS transfers power back to the standard source and shuts the generator down.  Automatic Transfer Switches are often used in high availability environments such as data centers, manufacturing plans, telecommunication networks and so forth. 

Can a generator I am looking at parallel with one I already own?
Generator sets can be paralleled for either redundancy or capacity requirements.  Paralleling generators allows you to electrically join them to combine their power output.   Paralleling identical generators will not be problematic but some extensive thought should go into the overall design based on the primary purpose of your system.   If you are trying to parallel unlike generators the design and installation can be more complex and you must keep in mind the affects of engine configuration, generator design, and regulator design, just to name a few.  For more information and details on paralleling standby generators in critical systems take a look at this informative article.9

Can you convert a 60 Hz generator to 50 Hz?
In general, most commercial generators can be converted from 50 Hz to 60 Hz by professional  engineer.  The general rule of thumb is 60 Hz machines run at 1800 Rpm and 50 Hz generators run at 1500 Rpm. With most generators changing the frequency will only require turning down the rpm’s of the engine.  In some cases, parts may have to be replaced or further modifications made.  Larger machines or machines already set at low Rpm are different and should always be evaluated on a case by case basis.  We prefer to have our experienced technicians look at each generator in detail in order to determine the feasibility and what all will be required.
How do I determine what size Generator I need?
Getting a generator that can handle all your power generation needs is one of the most critical aspects of the purchasing decision.  Whether you are interested in prime or standby power, if your new generator can't meet your specific requirements then it simply won't be doing anyone any good because it can put undue stress on the unit and even damage some of the devices connected to it.  Determining exactly what size of generator to get is often very difficult and involves a number of factors and considerations.  To get more detailed information on this subject, please visit our expanded article on Sizing a Generator.
 
 
Please be advised that all Manufacturer’s instructions, User manuals and Installation Guides take precedence over all and any of the tips listed below.
The information provided is merely intended to serve as a tip to the generator purchasing cycle. CableOrganizer.com cannot be held liable for any experience that deviates from what is listed below.
What is the process I will have to go through to get a generator installed and ready for back-up?
The generator process typically involves:
  1. Site Survey by a licensed electrician
  2. Selection of Generator
  3. Architectural drawing/ permit
  4. Natural Gas Installation
  5. Delivery of unit and placement of panel (this may be done before the gas source has been installed.)
  6. Electrical Installation
What should I consider when choosing a generator?
Get a generator that is rated for the amount of power that you can determine you will need.Look at the labels on lighting, appliances, and equipment you plan to connect to the generator to determine the amount of power that will be needed to operate the equipment. Choose a generator that produces more power than will be drawn by the combination of lighting, appliances and equipment you plan to connect to the generator including the initial surge when it is turned on.
How much outdoor space do I need for the generator?
Make sure you have adequate safe space outdoors to run the generator. In order to provide proper ventilation, some generators require 3-5’ distance on all sides of the generator – check your generator manual for specifics.
Is there someone that can help me decide what generator I need?
If you cannot determine any of the above, you can get our local distributor and ask for a site survey – an electrician will be able to help you make these determinations. You may also use our Generator Selector which contains wattage estimates for many common household appliances; including AC units, tools, refrigerators and even pressure washers.
What is included with the generator?
It is important to find out what does and does not come with the generator you are purchasing e.g. Transfer switch, composite pad (if not, cement slab may need to be poured, which may require a building permit being pulled), battery etc.
Will there be any other costs that I might incur?
Other than the cost of the generator, additional costs that you may incur include:
  • Installation cost
  • Gas or liquid propane cost
  • Lift gate cost
  • Generator Shipping cost
  • Battery cost
  • Permit fees
  • Architectural drawings (if necessary)
Generators come with an installation or owners manual. Be sure to always make reference to the manual if you have any doubts.
How long does a generator take to install?
It takes approximately eight to ten hours to install a standby generator. ** This would be subject to a site survey. Installation includes engine break-in and initial oil and filter change.
Does a generator need maintenance?
Depending on how often power goes out the engine oil and filter will need to be changed once per year or more.
Technical:
What is the difference between running watts and starting watts?
Running watts are the continuous watts needed to keep items running. Starting watts, are extra watts needed for two or three seconds to start motor-driven products like a refrigerator or AC unit.
How can I determine the running or the starting watt requirement for a tool or appliance?
First check the data plate on the tool appliance, if the running watts are not listed. You may use this equation:
Watts = Volts X Amps

Sizing a Generator - How to Determine What Size You Need

Getting a generator that can handle all your power generation needs is one of the most critical aspects of the purchasing decision.  Whether you are interested in prime or standby power, if your new generator can't meet your specific requirements then it simply won't be doing anyone any good because it can put undue stress on the unit and even damage some of the devices connected to it.  Unfortunately, determining exactly what size of generator to get is often very difficult and involves a number of factors and considerations. 
Making a choice amongst single phase, three phase, kW, KVA, welder, standby or motor starting generators can be mind-boggling. To prevent such confusion, this article was developed to help you get a better idea of how the sizing process works and some key things to keep in mind.  This is not a substitute for a certified electrician, which we always suggest talking to before buying, but it should provide you with enough information to get a solid understanding of some of the key things that are involved.

Generator Size Variations:  With the latest advancements in the field of electrical engineering, generators are now available in a wide range of sizes. Generators with power supply capacities of 5kW to 50kW are readily available in the personal and home use markets, while industrial generators are anywhere from 50kW to over 3 Megawatts.  Handy and portable gensets are available for homes, RV's and small offices, but larger businesses, data centers, buildings, plants, and industrial applications need to use the much larger sized industrial generators to meet their higher power requirements. 

Generator Sizing - How Much Power?:  Many people believe smaller generators can be used for standby electric power because they are not running all the time. This is not only a myth but can actually be very detrimental. Unfortunately, generator under sizing is one of the most common mistakes committed by buyers.  Not only does it involve the risks of damaging your new asset (the generator), but it can also damage other assets connected to it, create hazardous situations, and even limit overall productivity of the unit and/or the business relying on it.  If nothing else, the key thing to remember here is that more is always better than less.  
How to Determine the Right Size Engine or Generator: While there is no substitute for having a certified electrician perform an inspection and calculate everything for you, the guidelines below do offer some great starting points and should at least get you started in the right direction:
Know Your Requirements:  Going to a dealer and buying the best or cheapest generator available without any other consideration is clearly not the best approach. It is always better to delve deep into your power generation requirements before making a choice. You can do this in the following ways:
 
- Make a list of the items that need to be powered by the generator
- Make a note of the starting and running wattage of the respective items
- Calculate the total power requirements in KVA or KW
How to Find the Starting and Running Wattage: Getting the right starting and running wattage of the devices you intend to power is crucial for calculating the accurate power requirements. Normally, you will find these in the identification plate or the owner's manual in the buyer's kit of each respective device, tool, appliance, or other electrical equipment.
Ampere - Watt Conversion:  You may often find power requirements of tools stated in amperes. In order to convert the power requirement of a tool from ampere to watts, follow these calculations.
For resistive load: Wattage = amperes x volts

For reactive load: Wattage = (amperes x volts) x load factor
Power Requirement Charting: It often happens that you lose the owner's manual or for some reason can't find the power requirement specification of the tools and/or other electrical devices you're running. Here is a sample power consumption chart that demonstrates some of the typical wattages used for common appliances and tools.  The chart is simply provided as an example to demonstrate how starting and running wattages differ, and how each device has specific consumption needs.  If you have questions over any particular items you can contact the manufacturer, consult an electrician, or contact us for a free consultation.
Different ways of Calculating:  Depending upon the type and number of devices, and the way the generator is scheduled to be used, there are a few different ways of calculating power requirements:
-  Single motor running 
-  Multiple motors running simultaneously
-  No electric motors.
Advantages of choosing the right size generator: Now that you have an idea on how to choose the appropriate size of generator to suit your needs, here's just a few of the benefits obtained by going through that process:
- No unexpected system failures
- No shutdowns due to capacity overload
- Increased longevity of the generator
- Guaranteed performance
- Smoother hassle-free maintenance
- Increased system life span
- Assured personal safety
- Much smaller chance of asset damage
Where to Buy & Role of Dealers and/or Service Providers:  Since you are not only purchasing a substantial company asset, but most likely an item you will need to rely on for prime or emergency electrical power at some point, probably in a crisis, deciding where to buy is also a key consideration not to be overlooked.  The seller's years of experience, whether they are a full service dealer or small commissioned broker, and so forth, all play a role.  

Having been in the business for nearly a quarter of a century, here's just a few of the reasons why you should always consider Diesel Service & Supply, Inc. as your first stop for all your industrial power generation and diesel engine needs:
- 23+ years of industrial experience
- Full service multi-port garage
- Highly qualified mechanics and the industry's top diesel technicians
- High-end testing equipment and de-installation tools 
- Helpful support desk and knowledgeable office staff
- We test all our products
- Always a competitive price!
As this article demonstrates, there are obviously numerous considerations to account for when selecting the appropriate generator for the job.  If you are having a difficult time with it or would like more specific suggestions and recommendations for your situation, contact us today and one of our knowledgeable sales and support staff will be more than happy to assist