As we explore different components and elements of air compressors, we come across the all-important question – should I choose a direct drive or belt driven air compressor?

Many people feel that a belt driven air compressor is the best option.

That’s because they tend to be quieter and more efficient, provided the belt system is adequately lubricated. 

However, the flip side is that a belt will always need maintenance – and in time, you’re going to need to replace or repair that belt to avoid any downtime.

As with all air compression, the correct answer is all about your processes, applications, and the functionality you need from your compressor!

Here we’ll explain in a little more detail how a belt driven air compressor works and how it stacks up against a direct drive alternative.


Belt Driven Air Compressors vs Direct Drive

The first thing we need to note is that if you’ve settled on a rotary air compressor, the decision-making isn’t over.

These compressors come in both direct drive and belt drive models – each is a valuable piece of machinery but works very differently.

  • Belt driven air compressors have a belt connected to the compressor pump motor. As the motor runs, it turns the belt, which powers the pump.
  • Direct drive compressors have a crankshaft connected directly to the motor, without any part in between.

We’ve briefly mentioned the advantages and disadvantages of both designs, but it’s worth noting that direct-drive compressors can be easier to maintain.

They don’t require oil or lubrication and can be more powerful.


Is a Belt Driven Air Compressor Right for My Business?

Choosing a suitable compressor for your facility isn’t always easy, and there are benefits to both options.

If adjustability is a crucial factor, a belt driven air compressor is a good bet. You can adjust the power and speed as you need to, so they’re far more versatile.

That said, a direct drive compressor is a good investment if you’re hoping to minimise maintenance requirements or need a higher power output from your compression equipment.

Here’s a handy way to help identify the ideal solution:

  • Cubic feet per minute (CFM) is a vital metric – and establishes the volume your compressor needs to produce, depending on the application.
  • If you calculate all CFM demands for all processes, you can then add a 30% buffer to ensure you’re covered for any extra contingencies.
  • Don’t worry too much about having a belt or not, but base your choice on the CFM (or ACFM, actual cubic feet per minute). 

Investing in a compressor with the right speed, power, and capacity is the essential element. 

The ACFM is a useful figure since this is calculated according to different variables to give a more accurate output indication.


Benefits of a Belt Driven Air Compressor

Let’s summarise the benefits – and disadvantages – of a belt driven air compressor.

Pros of a Belt Driven Air Compressor

  • Belt driven compressors are more flexible, and you can change the pressure settings and run your compression at varying speeds and power as required.
  • For example, if you’re running pneumatic tools at 100 PSI, but your compressor is set to 90 PSI, you can replace the pulley, and you’re good to go.
  • Maintenance is often a downside to belt driven air compressors, but they remain economical and easy to maintain. Usually, it’s a case of lubrication and a monthly check on the belt tension.
  • You’ll need to factor in oil and filter changes, which are recommended between 500 and 1,000 hours of use.

Cons of Belt Driven Air Compressors

  • Wear and tear is a consideration, and if belts break, you will need to replace them.
  • It’s essential to check the pulley alignment regularly and make sure the belt tension is correct.
  • Improper belt alignment can impact the pressure at which the motor runs, causing overload or belt failure, so periodic inspections are vital.
  • Belt driven air compressors aren’t suited to exposure, so workplaces with very high or low temperatures are not ideal.

How to Choose the Right Belt Driven Air Compressor

As we’ve mentioned, the right compressor will depend on the applications of your rotary screw compressor and factors such as:

  • The environment in which the compressor will operate.
  • Frequency and duration of each expected use.
  • Initial budgets, energy efficiency, and maintenance considerations.
  • The flexibility requirements in terms of pressure and speed.

It’s also crucial to evaluate the performance of your chosen compressor regarding PSI, horsepower, CFM and RPM – each of these factors can affect the safety and functionality of your compressor, given the specific output and pressure requirements that come with each compressor.