How do I select the right machine?

Buying a compressor that is too small will waste valuable time and money. Buying a compressor that is too large will waste valuable fuel and money.
(If you are not using the air compressor outside you might consider a stationary air compressor, please refer to the section: How to select my stationary air compressor)

There are two parameters that determine the size of an air compressor:

1. Required operating pressure (Bar or PSI)
2. Maximum required air usage (Capacity in cfm, m³/min, ltr/sec)

1. What is the maximum required operating pressure?

This significantly depends on the type of work you are performing. For example, air tools typically require about 6 Bar of operating pressure. We usually select an air compressor rated at 7 or 7.5 Bar to compensate for the loss of air pressure in your air hose system. Blasting work (sandblasting) often requires the same working pressure. However, those working with blasting systems frequently desire more pressure, sometimes up to 9 or even 10 Bar. Pipeline testing applications often operate with 20 Bar or more. Optical fiberglass blowing systems mostly require a working pressure of 13-15 Bar.

2. What is the maximum required air usage?

To determine this, add up all the air tools or work that will be used simultaneously. When considering the compressor, add approximately 30% to the calculated air capacity. This addition serves as a reasonable buffer against unknown or uncommon compressor usage.

Avoid simply totaling all the air tools that will be used throughout the workday, as this will lead to an inflated capacity.

Below is a list of some air tools and their average air usage at 6.5 Bar (90 PSI):

• Angle Disc Grinder – 180mm / 7”: 180-280 ltr/min (5-8 cfm)
• Chipping hammer 2 kg: 350 ltr/min (12 cfm)
• Chipping hammer 5 kg: 430 ltr/min (15 cfm)
• Pickhammer 9 kg: 900 ltr/min (32 cfm)
• Paving / concrete breaker 15 kg: 750 ltr/min (27 cfm)
• Paving / concrete breaker 20/25 kg: 1300 ltr/min (46 cfm)
• Paving / concrete breaker 30 kg: 1700 ltr/min (60 cfm)
• Paving / concrete breaker 40 kg: 1850 ltr/min (65 cfm)
• Grease Gun: 115 ltr/min (4 cfm)
• Impact Wrench - 3/8”: 70-100 ltr/min (2.5-3.5 cfm)
• Impact Wrench - ½”: 115-140 ltr/min (4-5 cfm)
• Impact Wrench - 1”: 285 ltr/min (10 cfm)
• Needle Scaler: 220-455 ltr/min (8-16 cfm)
• Speed Saw: 140 ltr/min (5 cfm)
• Sandblasting 7mm nozzle @ 7 Bar: 5000 ltr/min (180 cfm)
• Sandblasting 10mm nozzle @ 7 Bar: 7000 ltr/min (250 cfm)

For sandblasting nozzle capacities, add 10-15% for nozzle cavitation and wear.

Do I need an air receiver tank with my air compressor?

The size of the compressor tank, usually measured in liters or m³, should align with the overall type of usage. In most cases, portable air compressors are modulation controlled and have significant hose lengths; therefore, receivers are not commonly used.

Budget

Your available budget sometimes limits the choice you have in the number of selected air compressors. We are here to help you find the right compressor for every budget. Once you have determined the required pressure, capacity, and budget, you can use advanced search to fill in these criteria, and you will find the right compressor for your needs.

How to Choose the Right Electric Air Compressor?

In the category: How to choose the right machine?

Choosing a compressor with insufficient capacity is a waste of time and money. Conversely, opting for a compressor with too much capacity results in wasted energy and money.

(If you do not use the compressor indoors or need to use it at different locations within your business, please refer to “How to choose the right mobile compressor?”.)

Determining factors for the capacity of an air compressor

There are two crucial parameters:

1. Required operating pressure (bar or PSI)
2. Maximum air usage required (capacity in cfm, m³/min, ltr/sec)

1. Maximum required operating pressure

The necessary pressure heavily depends on the type of work being performed. Pneumatic tools typically require about 6 bars of pressure. We often choose a compressor with a capacity of 7 or 7.5 bars, accounting for pressure loss in the piping system. Sandblasting work often requires the same working pressure, but those using sandblasting systems sometimes desire higher pressure, up to 9 or even 10 bars. Compressors used for truck maintenance generally have a capacity of 13 bars, while for engine start air, more than 30 bars are often needed.

2. Maximum air usage

Sum up all the pneumatic tools that will be used at the same time and add 30% to the compressor's capacity for unforeseen or unusual usage. Avoid overestimating the needed capacity by not summing up all tools used throughout the day.

Below is a list of pneumatic tools and their average air consumption at 6.5 bars (90 PSI):

• Angle Grinder – 180mm / 7”: 140-220 ltr/min (5-8 cfm)
• Chipping Hammer: 85-310 ltr/min (3-11 cfm)
• Cutting Tool: 115-285 ltr/min (4-10 cfm)
• Drill, reversible or straight-line: 85-170 ltr/min (3-6 cfm)
• Dual Action Sander: 310-370 ltr/min (11-13 cfm)
• Grease Gun: 115 ltr/min (4 cfm)
• Impact Wrench - 3/8”: 70-100 ltr/min (2.5-3.5 cfm)
• Sandblasting Head 7mm @ 7 Bar: 5000 ltr/min (180 cfm)

Do I need an air receiver tank with my compressor?

The size of the tank, in liters or m³, depends on your usage. For short and concentrated air supply, such as with a nail gun, a small tank suffices, while prolonged air usage, as with a wrench, sandblaster, or sander, requires a larger tank. The general rule is: the maximum capacity in ltr/min divided by 2 gives an indication of the needed tank size.

Electricity

The choice of a stationary compressor can be limited by the available power supply. Ensure your network is powerful enough to start and run the compressor.

Budget

Your budget may limit your choices. We are here to help you choose the right compressor, regardless of your budget. Once your criteria are defined, you can select the appropriate compressor through advanced search.

If in doubt or for assistance in selecting the right compressor, contact us at +32 56 61 67 01 or by email: sales@machineryresale.be.

How to Choose the Right Generator?

Selecting the appropriate generator capacity for your project or business is crucial but can prove complex. A poor choice, whether it's a generator that's too small or unnecessarily large, can lead to frustration and extra expenses. Here is how you can avoid this common mistake and select the ideal generator for your needs.

Determining the Right Capacity

Necessary Considerations

Generators are available in a wide range of capacities, from 5KW to 50KW and beyond. Your choice will depend on the wattage requirements of the essential equipment and lighting for your home or business. Carefully selecting the right capacity is key to establishing a reliable backup generator system.

Common Pitfalls

A frequent mistake is choosing a generator with insufficient capacity. This often happens to those who are not familiar with the specific formulas for calculating generator capacity.

Practical Examples

Condition #1 – Without Motor Loads

When your requirements do not include motor loads, you can sum up the total wattage of appliances and lighting to determine the needed generator capacity. For example, the sum of ten 100-watt lamps, a 1200-watt coffee machine, a 1250-watt toaster, and a 1500-watt hair dryer indicates a need for a 5 kW generator.

Condition #2 - With Motor Loads

In scenarios where motor loads are present, it's important to consider the starting wattage of motors. This ensures that the generator can provide the high starting current required. For appliances with induction motors, an additional 25% capacity is recommended. For instance, a heating device with a blower motor; upon starting, it alone would demand 4-6 kW from the generator.

Capacity in kVA

Capacity is often expressed in kVA. To calculate the required kVA from kW, divide the kW by 0.8. This is a useful rule of thumb for correctly estimating the required generator capacity.

By following these guidelines, you can make an informed decision when selecting the right generator, thus saving time, money, and ensuring a reliable power source for your needs.