How to stop generators, fans, and air compressors from vibrating

One thing that is often overlooked in dealing with generators (gen-sets), air compressors, and industrial fans is how they will be mounted. All of these devices create significant vibrations and need to be correctly secured using appropriate anti-vibration mounts. Let's look at a made-up situation for a demonstration. Suppose you have an air compressor that weighs 400 lbs. You could mount this directly to the floor or vehicle that it is riding on, but that would transfer the vibration and noise of the air compressor through the floor and vehicle that it is mounted to. A better solution would be to fasten the air compressor to the floor or frame of your vehicle with the use of anti vibration mounts. Mission Sales and Supply is a great source for a wide variety of vibration isolators. To determine the correct isolator to choose, I would start by visiting their Trelleborg Anti Vibration Mounts Index page. Here you can look for the appropriate category for the air compressor we are working with. Under the Stationary Installation section, we see that these mounts work well with compressors. Let's look at this particular mount.

Novibra M Anti-Vibration Mount

 

If you click on the image of this anti-vibration mount, it will take you to the product information page for this vibration isolator. That page will show you the mounts that are in stock as well as the price for each one. Above the table with the current stock information, you will find a link that says view information on selecting the correct vibration isolator. Click on this link to show the product specification page for the Novibra M. To find the anti vibration mount that will support the weight that we are trying to isolate, we take the total weight of our air compressor (400 lbs.), and divide that by the number of mounting positions (for this example we will assume there are 4). This will give us the load range we should look for on the specifications page. We are thus looking for a vibration isolator that will handle 100 lbs. (roughly 46 kg.). The second page of this pdf can look a little confusing: We start with Diagram 1. Look for the weight you are trying to isolate on the left hand side.

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We find about where 46 kg would fall on the right hand side and we move horizontally across the diagram to the right until we meet a slanted line. The first line we meet is the M100A. This chart is nice because the first slanted line you come to will typically be the mount that provides the best isolation for your desired weight range. If you would like to find the degree of isolation that this anti-vibration mount (M 100 A) will provide, first calculate what frequency your air compressor is running at. This chart uses Hz in its calculation. An easy way to calculate that would be to take the RPM you are running at (let's say 1800) and divide that by 60. This will give you the frequency in Hz (30 Hz). To find the degree of isolation for this anti vibration mount, move directly down into diagram 3 from the point where the weight range we were trying to isolate met the slanted line until you reach the desired Hz (shown on the left side of diagram 3). The slanted lines in diagram three are the degrees of isolation (which are seen on the right side of the diagram. You will see in this example, we pass all of the slanted lines and land below them. This means that this particular vibration isolator will have better than 90% isolation. Anything above 70 is going to be very good in terms of noise and comfort. We looked at this for just one of the anti-vibration mounts in that section. Repeat this process for any of the mounts that you see and compare the degrees of isolation as well as the overall design of the vibration isolator. If you have questions, the staff at Mission Sales and Supply is extremely knowledgeable and would love to run an analysis for you. 

Tuesday the 18th. Thanks for visiting Mission Sales and Supply - Marine Engine Mount and Vibration Isolator Specialists