Industrial Fans: Belt Drive or Direct Drive?

Determining the Optimal Drive for Your Industrial Fan

What makes your industrial fan whir? It’s a motor connected to your fan in one of only two ways: direct drive or belt drive. In the former, the motor connects to the fan wheel with nothing in between. In the later, there is a belt (sometimes more than one) connecting the motor to move the fan.

Deciding between a direct-drive fan and a belt-drive fan is fairly straightforward once you know all of your other variables, like fan size, application space, fan speed needs and likely wear and tear in your application. Let’s take a look at the differences to give you a baseline of criteria for which drive to choose in your application.

Direct Drive Fans

There are a number of reasons you might choose a direct drive fan. With the motor attaching directly to the fan wheel, the key benefits include:

Lower Maintenance: Direct drive fans require fewer parts, and thus, usually less maintenance. You have a fan, a motor, and maybe a coupling. When compared to belt drive fans, which require belts, sheaves, and bushings, direct drive is just plain simpler, and Maintenance folks tend to lean toward direct drive for daily maintenance.

Tighter Footprint: This type of fan arrangement is more compact, so it can often fit into a smaller space with the wheel either mounted on the motor shaft or directly coupled to the motor shaft. We frequently see this in applications that are constrained, requiring a compact design to fit the space.

Very Large Fan Applications: In larger fans over the 200 horsepower plateau, a direct drive can be significantly more efficient, adding to the longevity of the fan and motor. This is because of potential power loss when the belt tension pulls on the fan shaft in a lateral direction and burns out the motor too quickly.

Belt Drive Fans

There are several reasons why you may decide to use belt drive. Some key benefits include:

Speed Variation: Using a belt drive and various sheave sizes or diameters allows you to vary your fan speed. This can be especially helpful in material handling applications, in instances where initial estimates might be incorrect, or when speed specifications might change over time.

Less Wear & Tear: Sometimes you don’t want the motor to be as close to the fan operation as it needs to be for direct drive. Instead, you might want there to be a buffer of belts between a motor and a fan to absorb some of the wear and tear that the fan can’t avoid, but the motor can.

Hear it from the Application Engineer

Senior Application Engineer Chet White outlines the key differences in this 3½ -minute video.

When you’re ready to start your project, reach out and connect with one of our application engineers to discuss the details of your specification.

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