kVA Generator | 50-625 kVA Diesel Generator Sets

Q: What is the difference between kVA and kW on a generator?

kVA is apparent power, the total current the alternator and cables must carry. kW is real power, the part that does useful work. On a standard diesel genset the power factor is 0.8, so kW equals kVA times 0.8. A 100 kVA generator delivers 80 kW.

Q: What size kVA generator do I need?

Add the running kVA of every load that operates simultaneously, then check the starting kVA of the largest motor, usually 5 to 7 times its running current. The generator must cover both figures. Send the load list and we will size it, including the surge case.

Q: Do you supply generators between 50 kVA and 625 kVA?

Yes. The standard range runs from 50 kVA to 625 kVA prime, or 55 to 688 kVA standby, in 12 frame sizes with Cummins, Perkins, Volvo, Weichai, Yuchai, SDEC and Yangdong engine options. Larger sets up to 3000 kW are built to order.

Q: What is the difference between prime and standby kVA rating?

Prime rating is for continuous operation with a 10 percent overload for one hour in twelve. Standby rating is for mains failure only, limited to around 200 hours a year, and is typically 10 percent higher than prime. Running a standby-rated set as prime shortens its life.

Q: Can you supply 60 Hz and other voltages?

Yes. Standard build is 50 Hz at 400/230 V. We also build 60 Hz at 480/277 V, 440/254 V, 380/220 V and other site voltages. The kVA rating stays the same, only the alternator winding changes.

kVA Generator Range

Prime and standby ratings for every set we build — both figures shown, because the number on the nameplate is not always the number you can run.

Prime kVA (PRP)	Prime kW	Standby kVA (ESP)	Standby kW	Model
50 kVA	40 kW	55 kVA	44 kW	JJP-M40GF
75 kVA	60 kW	83 kVA	66 kW	JJP-M60GF
100 kVA	80 kW	110 kVA	88 kW	JJP-M80GF
125 kVA	100 kW	138 kVA	110 kW	JJP-M100GF
187 kVA	150 kW	206 kVA	165 kW	JJP-M150GF
250 kVA	200 kW	275 kVA	220 kW	JJP-M200GF
312 kVA	250 kW	344 kVA	275 kW	JJP-M250GF
375 kVA	300 kW	413 kVA	330 kW	JJP-M300GF
437 kVA	350 kW	481 kVA	385 kW	JJP-M350GF
500 kVA	400 kW	550 kVA	440 kW	JJP-M400GF
562 kVA	450 kW	619 kVA	495 kW	JJP-M450GF
625 kVA	500 kW	688 kVA	550 kW	JJP-M500GF

Sizing by kVA? Detailed pages: 100 kVA generator · 200 kVA generator · 250 kVA generator · 375 kVA generator · 500 kVA generator — amps per phase, dimensions, weight, fuel consumption and price for each size.

Ratings at 0.8 power factor, 400/230 V, 50 Hz. 60 Hz builds and other voltages quoted on request. Larger sets up to 3000 kW available — send us the kVA you need.

kVA vs kW: What Actually Changes the Quote

A kVA generator is rated in apparent power; a kW rating is real power. The gap between them is the power factor, and for a standard diesel genset that factor is 0.8. So a set sold as 100 kVA delivers 80 kW to the load — the other 20 kVA is reactive power the alternator has to carry but the load never converts into work.

This matters because the two numbers are not interchangeable in a quotation. If you ask for a 100 kVA generator and the supplier ships a 100 kW set, you have bought 125 kVA — roughly 25 percent more machine than you asked for, and you paid for it. If they ship a 80 kW set labelled as 100 kVA, you got what you asked for. Ask which figure is on the nameplate before you compare prices.

The formula

kW = kVA × 0.8 (power factor)
kVA = kW ÷ 0.8
Amps (3-phase) = kVA × 1000 ÷ (1.732 × volts) — a 100 kVA set at 400 V delivers about 144 A per phase

Motor loads, transformers and UPS systems all pull current that does not convert to useful work, which is why the kVA figure — not the kW figure — is what actually sizes the alternator and the breaker.

kVA to kW Conversion Table

The numbers buyers ask for most, plus the next size up in each direction.

Rating	Real power at 0.8 PF	Same kW, expressed in kVA	Same kVA, expressed in kW
50 kVA	40 kW	62 kVA	50 kVA
75 kVA	60 kW	94 kVA	75 kVA
100 kVA	80 kW	125 kVA	100 kVA
125 kVA	100 kW	156 kVA	125 kVA
150 kVA	120 kW	188 kVA	150 kVA
187 kVA	150 kW	234 kVA	188 kVA
200 kVA	160 kW	250 kVA	200 kVA
250 kVA	200 kW	312 kVA	250 kVA
312 kVA	250 kW	390 kVA	312 kVA
375 kVA	300 kW	469 kVA	375 kVA
437 kVA	350 kW	546 kVA	438 kVA
500 kVA	400 kW	625 kVA	500 kVA
562 kVA	450 kW	702 kVA	562 kVA
625 kVA	500 kW	781 kVA	625 kVA
688 kVA	550 kW	860 kVA	688 kVA

Why Buyers in the Middle East, Africa and the Commonwealth Quote in kVA

If you are sourcing from the UAE, Saudi Arabia, Nigeria, Ghana, Kenya, South Africa, the UK, Malaysia or Singapore, your tender documents and your consultant's load schedule will almost certainly be written in kVA. That is not a translation problem — it is the standard. IEC and BS practice sizes the alternator in apparent power, and the kVA figure is what appears on the datasheet, the type test certificate and the shipping documents.

Buyers in North America work the other way round, in kW and in amperes at 480 V. If you send a US-specification enquiry to a supplier who quotes in kVA, or the reverse, the two quotes will look 20 percent apart when they are describing the same machine. We quote both figures on every datasheet so the comparison is unambiguous.

UAE · Saudi · Qatar

kVA ratings at 50 Hz, 400/230 V. Ambient above 40°C derates the set — tell us the site temperature and the rating we quote will be the one that holds at that temperature, not the catalogue figure measured at 25°C.

Nigeria · Ghana · Kenya

kVA is the working unit across West and East Africa, and Perkins-powered sets carry a strong resale and parts reputation in this region. We supply Perkins, Cummins and Weichai options in the same kVA frame.

South Africa · UK · Malaysia

kVA plus a noise figure. Where a sound level is specified in the enquiry — 65 dBA at 7 m is common — a silenced canopy is a line item, not an upgrade nobody quoted.

How to Size a kVA Generator

Sizing starts from the load list, not from a rule of thumb. Three figures decide the rating:

Running kVA — the sum of every load that operates at the same time, with motor loads converted from kW to kVA at their own power factor (typically 0.8–0.85 for motors, higher for resistive loads).
Starting kVA — the largest direct-on-line motor will draw 5–7 times its running current for a few seconds. If that surge exceeds what the alternator can supply, the set stalls or the voltage collapses, no matter how comfortable the running load looks.
Duty — prime (PRP) for continuous or unlimited-hours operation, standby (ESP) for mains failure only. A standby-rated set run as prime will not last; the derating between the two ratings is real, not marketing.

Send us the load list and the duty and we will tell you which kVA rating covers it, including the surge case. Where the answer lands between two catalogue sizes, we say so rather than quoting the larger one to be safe.

kVA Generator Questions

What is the difference between kVA and kW on a generator?

kVA is apparent power — the total current the alternator and cables must carry. kW is real power — the part that does useful work. On a standard diesel genset the power factor is 0.8, so kW = kVA × 0.8. A 100 kVA generator delivers 80 kW.

How do I convert kVA to kW?

Multiply kVA by the power factor. At the standard 0.8 PF, 50 kVA = 40 kW, 100 kVA = 80 kW, 250 kVA = 200 kW, 500 kVA = 400 kW. To go the other way, divide kW by 0.8: 200 kW = 250 kVA.

Why do some countries quote generators in kVA instead of kW?

IEC and BS practice rates the alternator in apparent power, so tenders, load schedules and type test certificates across the Middle East, Africa, the UK and most of Asia are written in kVA. North America works in kW. Both describe the same machine — the conversion is 0.8 power factor.

What size kVA generator do I need?

Add up the running kVA of every load that operates simultaneously, then check the starting kVA of the largest motor — usually 5 to 7 times its running current. The set must cover both. Send us the load list and we will size it, including the surge case.

Do you supply generators between 50 kVA and 625 kVA?

Yes. Our standard range runs from 50 kVA to 625 kVA prime (55 to 688 kVA standby), in 12 frame sizes, with Cummins, Perkins, Volvo, Weichai, Yuchai, SDEC and Yangdong engine options. Larger sets up to 3000 kW are built to order.

What is the difference between prime and standby kVA rating?

Prime (PRP) is for continuous operation with a 10 percent overload for one hour in twelve. Standby (ESP) is for mains failure only, limited to around 200 hours a year, and is typically 10 percent higher than prime. Running a standby-rated set as prime shortens its life — the derating is real.

Can you supply 60 Hz and other voltages?

Yes. Standard build is 50 Hz, 400/230 V. We also build 60 Hz at 480/277 V, 440/254 V, 380/220 V and other site voltages. Tell us the frequency and voltage in the enquiry and the kVA rating stays the same — only the alternator winding changes.

kVA GENERATORS