We’re Constantly Asked Questions Regarding Our Generators, You Can Find Our Answers Below.
Many of our clients rely on our team to provide them with informative and accurate answers to all of their electrical, engine and generator related questions; this is why we’ve decided to put together a blog full of our FAQ’s.
What’s The Difference Between KW and KVA?
The main difference between KW (kilowatt) and KVA (kilovolt-ampere) is the power factor. Unless it is defined and known, the power factor is an approximate value, and the KVA value will always be higher than the value for KW. In relation to commercial and industrial generators, KW is most commonly used when referring to generators in the Unites States, and a couple of other countries that use 60 Hz. The majority of the world use KVA as the primary value when referencing generators.
Generators are usually shown with both ratings and to determine both the KW and the KVA ratio, this formula is used:
.8 (pf) x 625 (KVA) = 500 KW
What Is A Power Factor?
The power factor is sometimes referred to as ‘pf’, and is typically defined as the ratio between kilowatts (KW) and kilovolt amps (KVA) that is drawn from an electrical load. Power factor is determined by the connected load of the generator; the power factor on the nameplate of a generator relates to the KVA and KW rating (see the above formula).
A generator with higher power factors transfer energy to the connected load more efficiently, 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.
Standby, Continuous and Prime Power Ratings: What’s The Difference?
Standby generators are most often used in emergency situations, such as during a power outage. It is ideal for applications that have another continuous, reliable power source such as utility power. It’s recommended usage is most often only for the duration of a power outage and regular maintenance and testing.
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 and gas operations.
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. They generally include a 10% or so overload capability for short durations.
I’m Interested In A Generator That Is Not The Voltage I Need… Can The Voltage Be Changed?
Well, generators are designed to be either reconnectable or non-reconnectable. If a generator is listed as reconnectable, the voltage can be changed, ergo if the generator is non-reconnectable, it is not changeable. 12-lead reconnectable generator ends can be changed between three and single-phase voltages; however, be sure to keep in mind that a voltage change from three phase to single phase will decrease the power output of the generator.
Can A Generator I’m Looking At Run Parallel With One I Already Own?
Yes, generator sets can be paralleled for either redundancy or capacity requirements. Running generators parallel to each other allows you to join them electrically, to combine their power output. Paralleling identical generators will not be problematic but some comprehensive thought should go into the overall design, based on the primary purpose of your system.
Now, if you’re trying to parallel unlike generators, the design and installation can be more complex. It’s important to keep in mind the effects of engine configuration, generator design and regulator design.
Is It Possible To convert A 60 Hz Generator To A 50 Hz Generator?
Generally, most commercial generators can be converted from 60 Hz to 50 Hz. The general rule of thumb is 60 Hz generators 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 will be required.
How Do I Know What Size Generator I Require?
Getting a generator that can handle all of your power generation requirements is one of the most important aspects of the purchasing decision. If you’re interested in prime or standby power and your new generator is unable to meet all of your specific requirements, it won’t be doing anyone any good. Determining exactly what size of generator you need is often very difficult and involves a number of different factors and considerations.
It’s easiest to make a list of things you’ll need to consider, including:
- Items that need to be powered by the generator.
- A note of the starting and running wattages of the items.
- The total power requirements in KVA and KW.
