Cast iron piston compressor WK900-7-5/500P input power 5.5 kW, intake 880 l/min, pressure 10 bar, air receiver 500 l, voltage 400/50 V/Hz
Code: WK900-7-5/500P
Related products
Product detailed description
WALTER Cast-Iron Piston Compressor - WK900-7,5/500P
WK900-7,5/500P is the 5.5 kW class version with the largest pressure vessel: a 3W three-cylinder cast-iron unit, power input 5.5 kW, intake 880 l/min, effective delivery 740 l/min at 10 bar and 902 rpm, mounted on a 500 l horizontal tank. It does not differ from the 270 l tank variant by a single unit parameter – it only differs in how much air the machine has available before the motor must switch on. Power supply 400 V / 50 Hz, noise level approx. 80 dB(A), 3-year warranty after registration at waltercesko.cz.
A half-cubic-metre reserve is not bought for power, but for stable pressure in the distribution system. A 500 l tank delivers approximately 1,000 litres of free air per cycle at a typical two-bar switch differential, which is double that of the version with a 270 l tank. This is a machine for a workshop with a fixed distribution system, several take-off points, and sudden peaks – where average consumption is not the concern, but that minute when everyone draws air at once.
Configuration of this machine
- Cast-iron unit — 3W · 902 rpm · single-stage compression
- Pressure vessel — 500 l · horizontal
- Horizontal design
- Three-phase 400/50 V/Hz
- Standard pressure of 10 bar for common pneumatic tools
Why choose this model
1,000 litres of reserve per cycle instead of 540
The difference between the cut-in and cut-out pressure is typically 2 bar. A 500 l tank delivers approximately 1,000 litres of free air over this range, whereas a 270 l tank delivers only 540 litres. This is not about higher power – it is a larger buffer tank situated between your tool and the unit, cushioning every consumption surge before it manifests as a pressure drop on the gauge.
Approximately 11 motor starts per hour instead of 20
With a continuous draw of 300 l/min, a 500 l tank lasts about 3.3 minutes and refilling takes 2.3 minutes – the total cycle is therefore approximately 5.6 minutes, resulting in roughly 11 starts per hour. The same unit on a 270 l tank has about 20 starts under identical conditions. A piston compressor does not wear down from operating hours, but from starts: every start-up is a current peak and a moment when the lubrication film is at its thinnest.
Short-term capacity for draws exceeding 740 l/min
Tools that draw more than the machine provides are not automatically excluded – it is a matter of how long they run. At a draw of 1,000 l/min, there is a deficit of 260 l/min, which is drawn from the tank: from 500 l you can sustain this for approximately 3.8 minutes, from 270 l only 2.1 minutes. That is the difference between whether you can blast the whole part in one go or have to wait halfway through.
3W three-cylinder and 902 rpm – headroom, not speed
An intake of 880 l/min divided among three cylinders in a W-configuration ensures a smaller air delivery per cylinder, a smoother compression cycle, and a better-balanced crankshaft mechanism. The speed of 902 rpm is approximately 25% lower than the 1,202 rpm of the 3.0 kW class – with a comparable piston stroke, this means a proportionally shorter sliding distance of the piston ring per hour of operation.
Who is it for
It suits workshops with fixed piping and multiple take-off points where exact consumption cannot be planned: metalworking with a batch-used sandblasting box, a body shop with two bays and a preparation area, or a joinery with several machines on one air network. The common factor is that the machine is intended to remain in one place, be hard-wired, and not require daily manual intervention. Conversely, those who move the compressor around the workshop or lack the floor space for a 500 l tank will be more satisfied with the 270-litre version.
Typical applications
- Central source for fixed piping with three or more take-off points
- Batch sandblasting and blasting – the 500 l reserve covers peaks exceeding 740 l/min for several minutes
- Body shop: grinder, pneumatic chisel, and blow-off gun on a single circuit without pressure drops
- Paint shop with an HVLP spray gun in continuous operation, without pressure pulsations
- Metalworking with pneumatic clamping and tools that are triggered irregularly
- Operations where the machine is located in a separate room and the piping runs across the entire hall
Where to choose a different model
You sandblast or blast continuously, not just in batches
The tank cannot compensate for a permanent shortage; it only delays it by a few minutes. Opt for the four-cylinder 7.5 kW class with a delivery rate of 1,100 l/min on the same 500 l tank – it provides sufficient reserve even for a 3 mm nozzle in continuous operation.
You want the same performance but have limited space in the workshop
A horizontal 500 l tank occupies a significant footprint. The vertical version of the same 5.5 kW unit stands on a 270 l tank, reducing the footprint by approximately half. The trade-off is a smaller reserve: instead of 1,000 litres of free air per cycle, you get approximately 540.
You already own a pressure vessel with a valid inspection
Do not buy a second one. The 5.5 kW unit alone on a base frame can be connected to your existing tank – the inspection and certification remain your responsibility; we will confirm the scope of delivery by phone.
What the figures tell you — calculated values
The values are calculated and are meant for comparing the models with each other, not as guaranteed figures.
Design and technology
Related models and alternatives
WK900-7,5/270P
Same 5.5 kW unit on a smaller 270 l tank: smaller footprint, wheels, but approximately double the number of motor starts.
WK1500-10/500P
Same 500 l tank, but a four-cylinder 7.5 kW unit with a delivery rate of 1,100 l/min at 768 rpm.
VWK900-7,5/270P
Vertical version of the 5.5 kW unit with a 270 l tank – saves floor space where there is no room for a horizontal tank.
HWK1200-10/500P
When your equipment requires 13 bar: 960 l/min at 725 rpm on the same 500 l tank.
Frequently asked questions
- What specifically do I gain with a 500 l tank when the unit is identical to the 270P version?
- Three measurable benefits. The free air reserve per cycle increases from approximately 540 to 1,000 litres. The number of motor starts at a constant demand of 300 l/min drops from roughly 20 to 11 per hour. And you can maintain a short-term demand exceeding the machine's capacity – for example, 1,000 l/min – for about 3.8 minutes instead of 2.1. The output and working speed remain the same; what changes is the pressure stability and the load on the motor.
- Can it handle sandblasting?
- It depends on the nozzle and how long you blast continuously. A gun with a 3 mm nozzle consumes between 500 and 1,000 l/min. The machine can handle continuous operation up to approximately 700 l/min. Above 740 l/min, you are working from the tank reserve – at a draw of 1,000 l/min you have approximately 3.8 minutes before the pressure drops to the cut-in value and you must pause. For continuous sandblasting, the correct choice is the four-cylinder 7.5 kW class.
- How long does it take to fill the 500 l tank?
- The calculation gives approximately 6.8 minutes from zero to 10 bar without demand. This is an isothermal estimate based on the formula: tank volume multiplied by pressure divided by effective delivery; actual filling is usually slightly longer. In normal operation, however, the machine does not fill from zero – it only tops up by 2 bar between the cut-in and cut-out pressures. For a half-cubic metre tank, this practically means one thing: start the machine a few minutes before the shift begins and you won't have to worry about filling again.
- How much condensate accumulates in a half-cubic metre tank?
- Significantly more than in a smaller one, as the tank simultaneously acts as a cooler and all condensed water from 740 litres of discharged air per minute ends up at the bottom. Draining at least once a week is a requirement for this size, not a recommendation – un-drained condensate causes internal tank corrosion, water in the air, and consequently water in the oil, which can be identified by a lighter shade of the lubricant. Failure to comply with the prescribed maintenance is also grounds for rejecting a warranty claim.
- Can I move it around the workshop?
- Assume that you cannot. A half-cubic metre horizontal tank with a three-cylinder unit is a machine designed to be placed on a level surface and stay there – you will need a forklift or a pallet truck to move it. Delivery is via pallet transport, so please prepare equipment, not manpower, for unloading. If you need to move the machine around the workshop, choose the version of the same unit with a 270 l tank.
The machine comes with a 3-year warranty after registration with the importer. Warranty terms, the maintenance schedule and a comparison of all 28 models are in the category WALTER cast-iron piston compressors.
Ventilek’s tip
A big tank is like a full tank of petrol: the motor runs less often, and the air is there whenever you reach for the gun.
Additional parameters
| Category: | Air compressors |
|---|---|
| Warranty: | 3 years |
| EAN: | 5905122000158 |
| Compressor type: | Piston compressor |
| Pressure: | 10 bars |
| Suction power: | 880 l/min |
| Air delivery: | 740 l/min |
| Pressure vessel volume: | 500 L |
| Design of pressure vessel: | Lying down |
| Connecting: | Quick coupling DN 7.2, Ball valve 1/2" |
| Motor power: | 5.5 kW |
| Mains voltage: | 400/50 V/Hz |
| Speeds: | 902 rpm |
| Number of cylinders: | 3 |
| Number of grades: | 1 – single-stage compressor |
| Lubrication: | Oleic |
| Noise: | 80dB(A) |
| Dimensions: | 2000 × 610 × 1250 mm |
| Weight: | 253 kg |
| Accessories: | Pressure regulator, Wheels, Handle, Quick coupler, Ball cock |
| Engine: | Electric |
| Soundproofed: | No |
| Drive: | V-belts |
| Air dryer: | No |
| Retrieved from: | Professional |
| Development: | Stationary |
| In stock: | External warehouse |
Demonstrace výkonu litinového pístového kompresoru GK880-55-500 💪🏭
Product rating
Be the first who will post an article to this item!
WALTER Kompressortechnik - Innovative Solutions for Compressors
- About the company WALTER: WALTER Kompressortechnik is a renowned manufacturer of air compressors and accessories, known for its quality, reliability and innovative technologies. The company focuses on providing highly efficient solutions for various industries.
- Product portfolio:
- Screw compressors: we offer a wide range of screw compressors that are designed for maximum energy efficiency and long life. Ideal for high demanding industrial applications.
- Reciprocating compressors: these compressors are robust and reliable, suitable for smaller applications and workshops where high flexibility and low running costs are required.
- Mobile compressors: lightweight and easily portable compressors that allow easy use in a variety of locations, ideal for construction and field work.
- Scroll and special compressors: provide quiet operation and are suitable for specific applications requiring minimal vibration and noise.
- Innovation and quality: WALTER emphasizes continuous development and improvement of its products to ensure maximum customer satisfaction. Their compressors are equipped with advanced technologies to optimise performance and save energy.
- Customer support and service: the company offers comprehensive service, including installation, maintenance and diagnostics, ensuring the long-term reliability and efficiency of their equipment.
