FAQ's

In order to better inform our customers and website visitors alike on some of the most popular topics we encounter, we have decided to begin a list of FAQs. If you have any additional question, please email us with your suggestions and we will do our best to answer them.

1. 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. 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: .8 (pf) x 625 (kVa) = 500 kW

2. What is 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.

3. What is the difference between Standby, Continuous, and Prime power rating?

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.

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.

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.

4. What does an Automatic Transfer Switch do?

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 output of the machine. 10 lead reconnectable can converted to three phase voltages but not single phase.

5. 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