Top 10 Reasons Why a Strobe Light is an Analyst’s Best Friend: #4 – Belt Inspections

Belt inspections are singled out from other types of inspections due to the difficulty of using a strobe light on a lower frequency and belts often run at <500 rpm. Rather than a simple key or mark, you are trying to find some recognizable lettering on the back of the belts at a relatively slow flash rate – it can be virtually impossible.

An easier technique is to flash at least 1000 cpm or higher and lock in on a multiple of belt rpm rather than 1x. Once you have a lettering pattern frozen, you can tune away slightly and perform the same slow motion inspection on the belts, accurately assessing belt condition even while flashing at 2x or 3x belt speed.

This tip is provided by Scott Dow, Senior Instructor of Mobius Institute.

Come back to our blog next week to read #3 in our Top 10 Reasons Why a Strobe Light is an Analyst's Best Friend. To learn more about IMVAC and the event nearest to you, visit vibrationconference.com.

Top 10 Reasons Why a Strobe Light is an Analyst’s Best Friend: #5 – Belt Drives: Bent Shafts and Pulley Wobble/Runout

Although a dial indicator would be the preferred method for accurately determining the degree of faults like these, a strobe can often help when the machine cannot readily be shut down. We start with the same basic Slow Motion Study approach (are you sensing a pattern…?)

Starting with the driven shaft, by lining up the edge of the pulley or shaft with a fixed point on some structure behind it, you can watch for any movement of the shaft that shouldn’t be there in both the radial direction (runout, eccentricity, bent shaft, etc.) and the axial direction (cocked pulley, bent shaft, etc.).

This tip is provided by Scott Dow, Senior Instructor of Mobius Institute.

Come back to our blog next week to read #4 in our Top 10 Reasons Why a Strobe Light is an Analyst's Best Friend. To learn more about IMVAC and the event nearest to you, visit vibrationconference.com.

Top 10 Reasons Why a Strobe Light is an Analyst’s Best Friend: #6 – Structural Looseness

Ever see amplitudes increase drastically at 1x? Did you know that a strobe light is a great way to inspect for structural looseness, often the cause of such a sudden increase (literally – something broke)? To do this, we utilize the very same Slow Motion Study techniques we discussed previously.

By tuning to the frequency of interest and then tuning slightly away from that, you will be amazed at some of the things you can see happening on the structure. Sometimes you need to play a bit with your flash rate but you will find this to be a useful technique in finding broken welds, loose feet, housing distortion, loose and broken fasteners and many more causes of abnormally high amplitudes.

This tip is provided by Scott Dow, Senior Instructor of Mobius Institute.

Come back to our blog next week to read #5 in our Top 10 Reasons Why a Strobe Light is an Analyst's Best Friend. To learn more about IMVAC and the event nearest to you, visit vibrationconference.com.

Top 10 Reasons Why a Strobe Light is an Analyst’s Best Friend: #7 – Verifying 1x

One mistake I’ve seen made over and over is an analyst fails to verify that what they believe to be 1x is actually 1x. This happens for one simple reason: more than one single flash rate will cause a single mark to appear. What about 1/2x, when the flash rate is once every two rotations? Or 1/3x?

The simple test is to double your flash rate from what you believe to be 1x. If two marks appear, meaning you are now flashing twice per rotation, you are correct. If not, you have more work to do.

This tip is provided by Scott Dow, Senior Instructor of Mobius Institute.

Come back to our blog next week to read #6 in our Top 10 Reasons Why a Strobe Light is an Analyst's Best Friend. To learn more about IMVAC and the event nearest to you, visit vibrationconference.com.