Advatech
After Sales Support

kW stands for kilowatts (1000 watts) and kVA stands for kilo-volt amperes (1000 volt amperes). kW represents ‘actual power’ an electrical system has. It shows how much power is being transformed into useful output. While kVA represents ‘apparent power’ that shows how much is being used. The primary difference between kW and kVA is the power factor or efficiency of the electrical system. The average power factor of a generator set is 0.80.

Standby Generator set is a backup genset which is used for emergency situations only like blackouts (“brownouts”). It is intended to run for a short period of time at variable loads until the main power source is back.

Prime Generator set on the other hand is intended to run for a long period of time at variable loads as the primary source of power for the operation and generally has around 10% overload capability for a short period of time. It is used mostly in remote areas like mines and construction sites where there is no power grid.

Continuous Generator set is almost similar to Prime Generator set. The difference is that Continuous Generator set has base load rating which means is can run for a long period of time but at a constant load.

The formula to calculate kVA if kW and power factor (pf) is given is, kVA = kW ÷ pf.

Example:              kW = 200, pf = 0.80

                                kVA = kW ÷ pf

                                kVA = 200 ÷ 0.80

                                kVA = 250

The formula to calculate kW if kVA and power factor (pf) is given is, kW = kVA x pf.

Example:              kVA = 250, pf = 0.80

                                kW = kVA x pf

                                kW = 250 x 0.80

                                kW = 200

Sizing a generator set is a bit complicated and so it must be dealt with utmost care. The generator size/rating that you need will depend on a number of factors. It is advised that you consult one of our Account Managers/Sales Engineers or a qualified Professional Engineer that can compute the best generator size for you.

1. Loads (equipment): Whether it is full load or select loads only, you must identify all the equipment that you will be running so that you can choose the right genset size/rating. Buying too big genset will cost you to spend significant amount of money and not maximizing the genset’s capacity or it could lead to genset underloading. While buying too small genset can lead to overloading or operating fewer equipment than what you have planned.
2. Genset designated location: It is important that you have identified a good area to install your genset. It has to be structurally stable and with levelled base. You sure wouldn’t want to buy a big genset only to end up not able to use it because of space problem.
   1. For Open-type genset: It is a must that the genset is installed inside a room or under an enclosed area to protect the genset from outdoor risk especially from the elements of weather. The area must be well ventilated and spacious enough to allow a comfortable access for the operator during operation and maintenance. Typically, a minimum of 1 meter distance on all sides of the genset must be clear of any obstruction. The room must have (a) an area where the genset can get a sufficient amount of fresh air to help cool the genset unit and (b) an area where the exhaust and hot air produced by the genset unit are directly expelled out of the room. In this circumstance, an exhaust pipe extension and radiator ducting are needed to be installed.
   2. For Silent-type (with enclosure) genset: Usually, this type of genset is installed in an open area (no walls and/or roof) or outside of any structure since it has a soundproof and weatherproof enclosure to protect it. Just don’t forget to consider your nearest neighbor or the requirements of your subdivision when it comes to installing a genset. However, if the genset will be installed inside a room, you may refer to ‘a. For Open-type genset’.
3. Installation: Typical genset installation requires the following:
   1. Radiator ducting – Used to expel hot air from the genset radiator. Not needed when genset is installed outside of a room.
   2. Exhaust pipe extension – Used to expel smoke, fumes and hot air from the genset engine. Needed when genset is installed inside a room.
   3. Power cables – these are the wires that usually connects the genset and the transfer switch; Automatic Transfer Switch (ATS) or Manual Transfer Switch (MTS)
   4. Ground cable – this is the wire that connects the genset system directly to the earth.
   5. Control wires (when using ATS only) – these are the wires that allows the ATS to control the genset during any power interruptions.

Advatech’s standby rating generator set can run continuously for 8-hours at 100% full load. However, it is advised that during genset operation, the fuel (diesel) level should be closely monitored and/or re-filled to avoid unnecessary shutdown.