300 kVA power class
300 kVA Diesel Generator (240 kW)
A 300 kVA diesel generator delivers 240 kW at a 0.8 power factor. This is the rating that appears in hospital, cold store and food processing specifications, because it is the smallest size that can normally carry a building services load while still accepting the load step of a chiller or a large compressor.
Ratings
Ratings at a glance
| Parameter | Value |
|---|---|
| Prime power (PRP) | 300 kVA / 240 kW |
| Emergency standby (ESP) | 330 kVA / 264 kW |
| Rated voltage and frequency | 400/230 V, 50 Hz (380/220 V or 60 Hz on request) |
| Rated speed | 1500 rpm, four-pole (1800 rpm for 60 Hz) |
| Full-load current | 433 A per phase at 400 V |
| Typical duty | Standby for building services and technical loads; prime power for cold stores and plants |
Specification envelope
What is normally inside a 300 kVA set
| Item | Typical range | Why it matters |
|---|---|---|
| Engine | Six-cylinder, 9.0-11.0 L, electronic governor | Load step recovery with chillers and compressors |
| Alternator | Brushless, class H insulation, IP23, AVR controlled, 2/3 pitch common | Harmonic content with non-linear loads |
| Fuel consumption | 43-49 L/h at 75% load (180 kW) | Fuel planning for long outages |
| Base tank autonomy | 400-500 L, 8-10 h at 75% load | One shift or one day of autonomy without a bulk tank |
| Noise at 7 m | 67-74 dB(A) canopy, 80-86 dB(A) open frame | Boundary limits at hospitals and hotels |
| Weight | 2.6-3.2 t open, 2.8-3.4 t canopy | Slab design and crane or forklift access |
| Footprint | Approximately 3.9-4.4 m x 1.4 m canopy | Yard space and service clearance |
Sizing
What decides 300 kVA or 400 kVA
- Chiller staging. One chiller compressor may be under 240 kW of running load, but the permitted start kW of the set is what limits the design. If the sequence starts two compressors together, the next rating up is usually the honest answer.
- Non-linear loads. Variable speed drives, LED lighting and UPS systems add harmonics. A 2/3 pitch alternator and a generously sized neutral are common answers, and the alternator has to be checked against the harmonic current.
- Cold store pull-down. Refrigeration compressors running at full load after a defrost or a door opening behave differently from a steady load; the peak is what the set has to accept.
- Redundancy. Where two sets are wanted for N+1, most projects buy two 300 kVA machines rather than one large set and a small standby, so that either machine can carry the critical bus alone.
Applications
Typical 300 kVA applications
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Hospitals and clinics
Operating theatres, sterilisation, medical gas plant and refrigeration, defined by an essential load bus rather than the whole building.
-
Cold stores and food processing
Compressor loads with a high starting demand and a long running period after a mains failure.
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Malls and mid-size hotels
Standby for lifts, lighting, pumps and part of the air conditioning, with an ATS on the essential board.
-
Quarries and batch plants
Crushers and mixers that start on load, often as prime power on sites with a weak grid connection.
Options
Options usually specified at 300 kVA
| Option | What it changes |
|---|---|
| ATS rated 630 A | Changeover for the essential board, interlocked so that the mains and the set can never be paralleled accidentally |
| Alternator winding | 2/3 pitch and a full-size neutral where drives and UPS loads dominate |
| Enclosure | Canopy with critical silencer, or containerised where the set stands outdoors for years |
| Control panel | AMF with alarms and event log; remote monitoring where the site is unmanned |
| Fuel system | Bulk tank with a transfer pump and a day tank, where autonomy beyond one day is required |
Questions
300 kVA questions we are asked
How many amps does a 300 kVA generator produce?
433 A per phase at 400 V three-phase. A 630 A main device is the usual choice, which leaves headroom for the standby rating of 330 kVA, or 476 A, without changing the switchgear.
What size tank gives 8 hours of running?
At 75% load the set burns 43-49 L/h, so 8 hours needs roughly 350-400 L of usable fuel. A 500 L base tank covers that with a margin and keeps the fuel below the usual bunded-tank thresholds.
Can the same set run in parallel later?
Only if it was ordered with a paralleling-capable control panel and a suitable alternator. Retrofitting parallel operation means replacing the controller and adding load sharing and protection, so it is cheaper to specify it at the quotation stage even if the second set comes later.
How much does a 300 kVA generator weigh and how much space does it need?
Around 2.8-3.4 t in a canopy, on a footprint of roughly 4.4 m by 1.4 m. Allow at least one metre clear on the radiator and door sides for airflow and service access, and a lifting plan for the installation day.
Is 300 kVA enough for a small hospital?
For the essential load of a small hospital it usually is, provided the block load is staged. The decisive number is not the total connected kW but the largest load step the engine can accept, and the medical gas, theatre and refrigeration loads have to be listed individually.
Related
Other pages in this range
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Diesel generator sets
Ratings, voltage and frequency combinations, and what belongs in an enquiry.
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200 kVA
160 kW, for smaller essential boards and single critical loads.
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400 kVA
320 kW, the next step where chillers start together.
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Request a quote
Send the load list and site conditions, and we reply with the rating and build options.
Need a 300 kVA specification?
Send the essential load list, the largest load step and the site conditions. You will get a rating, a fuel figure and the alternator and switchgear that go with it.