How to choose a 100 to 270 litre compressor for the workshop

A compressor of 100 to 270 litres is the typical choice for a workshop, a body shop or a small department where two or three pneumatic tools work together. In the AMES collection you will mostly find belt-driven piston compressors, from 3 to about 11 HP, with maximum pressures of 10, 11 and 14 bar. A 200 or 270 litre tank and a power between 4 and 7.5 HP cover most cases; below 100 litres the air runs out quickly, while beyond that, for continuous duty, it is worth looking at a screw compressor.

The types

• Belt-driven piston: the most common type. The motor drives the pump unit through a belt (A39B, A49B, B5900, B6000 and similar). One example is the LN1 A39B 270 with 270 litres and 4 HP.
• Two-stage: compresses the air in two phases, for higher pressures and better efficiency on the larger models.
• Silenced: with a sound-absorbing canopy, for working where there are people. An example is the Pulsar Evo BK113-4.
• Vertical: takes up less floor space, useful when space is limited.
• Petrol engine-driven compressor: for those who work where there is no mains power. It is used outdoors only.

How to choose by job

The features to look at

Tank capacity. The data show 150, 200 and 270 litres (a few data sheets give 500). A large tank does not increase the flow rate, but it keeps air available for peaks and makes the motor start less often.

Power (HP). From 3 to about 11 HP. This is the motor power, not how much air reaches the tool: always look at the flow rate of the pump unit as well.

Maximum pressure. 10, 11 or 14 bar. For most tools a few bar at the outlet are enough, so 10 bar is already a good starting point. Take 14 bar only if you have equipment that really requires it.

Power supply. Electric 230/400 V, single-phase or three-phase, or petrol. The more powerful models require three-phase.

Noise. Between 62 and 97 dB(A): the difference between a silenced and a standard model is huge if you work in an enclosed space.

Weight and dimensions. From about 105 to 265 kg, with lengths between 1.45 and 2.05 metres: measure the doorway before ordering.

How to match tools and compressor. List what you will use together, read the air consumption on the tool data sheets and add it up. Choose a compressor whose flow rate exceeds that total, then decide the tank according to how long the periods of continuous use are. An impact wrench used in bursts consumes in jerks and the tank acts as a buffer; a spray painting gun consumes steadily and tests the flow rate.

Common mistakes

• Looking only at the litres of the tank: the flow rate of the pump unit and the HP matter too.
• Underestimating the noise, then finding that nobody can stand more than an hour in the department.
• Not checking the electrical line: a 7.5 HP three-phase on an unsuitable installation trips the protections.
• Using pipes and fittings that are too narrow, which waste the pressure produced.
• Not draining the condensate every day and not checking belt tension and filters.

Frequently asked questions

How many HP does a workshop need?

For two or three tools at the same time you are usually between 4 and 7.5 HP. The exact figure depends on the air consumed by the tools, which you will find on their data sheets.

200 or 270 litres?

If the tools work in bursts or with high consumption, 270 litres gives more autonomy. For lighter use 200 litres is enough.

Belt-driven or direct-drive?

In this range the collection consists mainly of belt-driven models, designed for daily, prolonged use in the workshop.

Do I need three-phase?

The more powerful models do; below that there are also versions powered at 230 V. Always check the data sheet and the electrical line before ordering.

What does "S" or "Extensive" in the name mean?

They are series names from the manufacturer. They do not indicate size on their own: look at litres, HP and pump unit in the data sheet.

You can find the models in the Industrial Compressors – 100 to 270 Litres collection: to choose the right match between tools and compressor, request a quote or ask the AMES technicians for advice.