Standard Approach – New Guidelines on Shaft Alignment and Machinery Installation

You can also find this article in MRO Magazine’s April Digital Edition here.

The new standards in shaft alignment and machinery installation are a must-have for anyone involved in rotating machinery.

Without a doubt the most important aspect for rotating machinery is the installation or re-installation of the machine. There are other factors, such as operational procedure and design faults – even incorrect lubrication – however, the main factor is the installation. This is the critical element that dictates the life expectancy of the machine. The famous study of Nowlan and Heap tells us that only 11% of rotating machines run to their full life expectancy. Even if you disputed this study, consider the billion-dollar Industrial Supply Industry that supply’s us with chains, sprockets, belts, sheaves, pumps, motors, gearboxes and so on. If we say that the study is correct then we have to admit that we do not do a good job as installers and maintainers of rotating machines.

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Machine Life Expectancy – What should the maintenance organization focus on?

You can also find this article it in MRO Magazine’s December Digital Edition here.

Recently I have been seeing the P to F interval curve popping up a lot on my LinkedIn feed and in articles that I have read. It was a concept that I was first introduced to when I was implementing Reliability Centred Maintenance into the Engineering and Maintenance department at the plant where I worked at the time. It was a great idea, that if done correctly is maintenance benefit. Why, because its cost savings and cost avoidance. Let me explain this.

Life Expectancy of a Machine - P to F curve

Fig 1. The P to F Interval Curve.

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Maintaining Growth in the Wind Power Industry

You cannot say it’s a new industry because its been around for quite some time however, you can call it a growth industry because yes, it’s still growing. In fact, I can see it getting bigger. My reason for this is that I can see some remote communities taking advantage of this technology, technology that is improving with better power storage for example. I can also see some large manufacturing plants generating their own power to save on the costs because as we know, power is expensive to buy. I cannot say that we are there yet but as costs come down it looks like a viable alternative to what we do now in many cases.

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Dowel Pins: Should we be using them for pinning general purpose machines?

Figure 1 (above) – Can you see the dowel pin in this photo?

Dowels have been used by carpenters for centuries. They would have a length of rod which they would cut the required amount needed from it. It would have been inserted into a joint to give the joint more strength and to stop or reduce the share of forces that are on that joint. Basically, a pin to keep something in the same position. It is not designed to be fastener or a clamp, as something else would meet this requirement. So it’s no surprise that we see them in our industry.

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Understanding Thermal Growth in Your Rotating Machinery – Part 3

There are other issues we should be aware of when talking about a machine’s thermal growth in our rotating machinery and how it affects the machine’s alignment at the coupling. One major factor affecting machinery alignment is Dynamic pipe strain caused by thermal growth. However, there are two types of pipe strain and the other type is also important to know about. Static pipe strain exists when the machines are not even operating. Static pipe strain is a major cause of machine failures and is the result of incorrect fabrication and/or installation, inadequate or missing support, or machine movement after piping is connected. Its effects are relatively simple to measure however, it’s often ignored because repairs or rework are perceived to be costly, but that’s not always the case.

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Understanding Thermal Growth in Your Rotating Machinery – Part 2

In the first part of this article (click here for Understanding Thermal Growth in Your Rotating Machinery – Part 1), we defined what thermal growth in machines is. We used an example of a machine growing equal amounts in the vertical direction. The fix was to lift or lower the machine of choice by a total of 5 thou (0.005“) to compensate for the growth offset. To reiterate this example a little further see below the temperature readings we took on a motor running at approx. 1800 rpm. The first reading (PHOTO – below) the front foot is 51° C and the next reading (PHOTO – below) the back foot is 38° C.

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Understanding Thermal Growth in Your Rotating Machinery – Part 1

Thermal growth is an issue that is very much ignored because many think it too complicated to calculate and compensate for. Some are even unaware that it is an important issue that should be considered. So our aim is to address this issue and hopefully simplify it so that it can be measured and compensated for on a more regular basis. We will do this over a three-part article – Part Two and Three will follow in the New Year. So excuse the pun but we want thermal growth to be the hot issue in 2016!

Fig.1 An example of how hot liquids in the piping could pull the pump up, creating a twist or bent base frame as well as a misalignment between the shafts of the pump and motor.

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Getting the Right Angle in Shaft Alignment

Getting the right angle can pull you out of a jam.

When we think of shaft alignment we usually think of one machine being the stationary and the other machine being the moveable. The normal preference is to use the driven (ie. pump) as the stationary and the driver (ie. motor) as the moveable. The reason behind this is that you don’t want to create pipe strain by moving the pump. Makes sense right? For some who don’t think beyond this, it limits their options. The reality is that you can move either machine and in fact, in the case of say, a diesel engine that is driving a generator, it’s the driven that is normally chosen to be the movable. However, very often moving a combination of both machines will give you the best option with the least amount of correction.

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Alignment Problems: Dancing with a Soft Foot

Alignment of machinery is critical in plant operations, and soft foot conditions are especially troublesome. Here’s how various alignment systems can help.

You would probably think it foolish to have work done on the front end of your car and not have the alignment checked and if necessary adjusted. If the front end is out of alignment the car would start to vibrate, sometimes excessively, right up the steering column into your hands. This would undoubtedly put greater stress on the front suspension and steering, causing expensive damage. You will see this most of all in the tires. You can go through a set of tires pretty quickly when the front end is out of alignment. In addition, your fuel usage will increase because of the extra power required to push that misaligned car around.

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Student Millwrights: Why not hire one for the summer?

Summer is upon us and hopefully the livin’ is easy! For some in the mechanical maintenance world the summer time is a slow time; for others, it’s go go go. For instance, in cement plants they have their maintenance shut down in the winter months when it’s slow because their summer is full steam ahead for production. No matter what industry you’re in, one of your pressing problems is making sure that you have adequate maintenance coverage or man-power over the vacation period. You need the coverage because break downs can happen and do happen when least expected. And how are your staffing levels going into the summer? Most companies I see are still very lean and mean and could actually add one or two new staff members. However, this is deferred. Why? Well because it’s the summer and someone said lets hold off until the fall to get the extra bodies!

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