Skip to main content

ELECTRIC MOTOR VIBRATION ANALYSIS

What is the importance of vibration analysis in electric motors?

Vibration characteristics and balancing


Vibration is defined as a mechanical fluctuation from an equilibrium point. Vibration can also be considered as period vibration. Period vibration is a random vibration or pendulum motion of an object. An example of this is the movement of tires when moving on a gravel road.


There are different types of vibrations that we experience everyday. These are both desirable and undesirable. It is important that we have a basic understanding on vibration analysis and some of its principles.


The most commonly used method for rotating machines is called vibration analysis. Measurements can be taken on machine bearing casings with seismic or piezo-electric transducers to measure the casing vibrations, and on the vast majority of critical machines, with eddycurrent transducers that directly observe the rotating shafts to measure the radial (and axial) vibration of the shaft. The level of vibration can be compared with historical baseline values such as former start-ups and shutdowns, and in some cases established standards such as load changes, to assess the severity.

What is vibration?

Vibration is a "back and forth" movement of a structure. It can also be referred to as a "cyclical" movement.

Benefits

1. Safety - failure of electrical components could be catastrophic, injuring or even killing employees, maintenance personnel or the public.

2. Greater System Security - locate the problems prior to failure greatly reduces unscheduled outages, associated equipment damage and downtime.

3. Increased Revenue - with more uptime, revenue is maximized. With less maintenance on good components and faster repairs of faulty components, maintenance costs care are reduced leading to a better bottom line.

4. Reduced Outage Costs - the cost of an emergency outage is ten times greater than planned maintenance.

5. Reduce Spare Parts Inventory - with improved inspection techniques giving advanced warning of failure, fewer spare parts are required in inventory. What would it mean to the bottom line if your spare parts inventory could be reduced by 10%?

6. Reduced Operational Costs - with the system up and running for longer periods of time, the reduction and improvement of inspections, maintenance, spare parts inventory and outages will reduce the overall cost of operations.

Comments

  1. How is the vibration of a motor measured (in what units)? Do you happen to know where I can find a ranking of motors by least to most vibration over the life of a motor? Or measured in random testing in an apples-to-apple comparison?

    Thanks
    Chris

    ReplyDelete

Post a Comment

Popular posts from this blog

PARTS OF A POWER TRANSFORMER

What are the name of the basic parts of a Power Transformer? We can not deny the fact that only a handful of electrical engineering students are presently familiar with power transformers especially on what it looks like. Unlike a transformer we found in our homes, a power transformer’s appearance and construction is somewhat more complicated. It is not just a simple winding with a primary and secondary terminal although basically any transformer has one. The function that a power transformer plays in an electrical system is very important that an electric utility can not afford to loss it during its operation. Our discussion here will focus more on the basic parts and functions of a power transformer that are usually tangible whenever you go to a substation . Although not all power transformers are identical, nonetheless they all have the following listed parts in which the way of construction may differ.

ELECTRIC MOTOR FRAME SIZE STANDARD SPECIFICATIONS

ELECTRIC MOTOR FRAME SIZE STANDARD SPECIFICATIONS How is electric motor frame size being specified? Motor frame dimensions have been standardized with a uniform frame size numbering system. This system was developed by NEMA and specific frame sizes have been assigned to standard motor ratings based on enclosure, horsepower and speed. The current standardized frames for integral horsepower induction motors ranges from 143T to 445T. These standards cover most motors in the range of one through two hundred horsepower. Typical example of where you can locate the frame is shown in Fig 1.2.D – Frame No. The numbers used to designate frame sizes have specific meanings based on the physical size of the motor. Some digits are related to the motor shaft height and the remaining digit or digits relate to the length of the motor. The rerate, or frame size reduction programs were brought about by advancements in motor technology relating mainly to higher temperature ratings of insulating mate...

ELECTRIC MOTOR NAMEPLATE SPECIFICATIONS

How do we interpret an electric motor nameplate? Motor standards are established on a country by country basis.Fortunately though, the standards can be grouped into two major categories: NEMA and IEC (and its derivatives). In North America, the National Electric Manufacturers Association (NEMA) sets motor standards, including what should go on the nameplate (NEMA Standard MG 1-10.40 "Nameplate Marking for Medium Single-Phase and Polyphase Induction Motors").