Choosing the Right Electric Vibrator Motor: What Actually Matters
When choosing a motor for your vibratory application, there are several factors you should take into consideration before making your purchase. It is very easy to get overwhelmed with all the options available in a supplier’s catalog. Buyers tend to focus too much on the specifications such as voltage requirements, force ratings, etc. and overlook the true requirements of their vibratory application. While the specifications of the motor may seem appealing, many times they are misleading.
If you don’t know exactly what you need, you will either end up paying for features that you do not need, or worse yet, you will end up with a motor that will not be able to keep up with your workload. The real key to selecting the right electric vibrator motor is to understand the specific operation that you are going to use it for.
It’s not the brochures version of industrial activity; it’s the actual day-to-day activities that occur during your operation. The characteristics of the material being processed and the actual operational conditions of your motor will greatly impact the selection of the correct motor.
Understanding Your Operation Before Looking at Specs
Before you start looking at the specifications of electric vibrating motors, think about what you want to accomplish. Do you need to move sticky product out of a hopper? Do you need to get wet concrete to set in a form? Do you need to compact product as it travels along a conveyor? All of these tasks will require a different amount of energy (or force) from a vibratory motor. If you do not understand this, you will either not be satisfied with the performance of the motor, or you will pay for unnecessary capability.
The characteristics of the material being processed, whether it be fine powder or aggregate product, will make a big difference in how a motor performs. Wet materials will create different challenges than dry materials. Temperature will also affect motor performance; a motor that is rated for normal temperature will not perform as well as a motor that is rated for extreme temperatures (for example, a motor used in a foundry environment will perform better than one used in a cold storage area).
Mounting Requirements Must Be Taken Seriously
Some applications will require motors to be mounted directly to the frame of the equipment, whereas other applications will require the motor to be mounted independently of the equipment so that the direction of the vibration can be controlled. When the motor is chosen to match the mounting requirements of the operation, numerous problems down the road are avoided. Additionally, excessive vibration will not only reduce the effectiveness of the motor, but could also cause damage to the motor and the equipment.
Specifications That Relate To Performance and Power
While many manufacturers advertise the "force" ratings of their motors, these ratings may not be the most important specifications to consider. What is truly important is whether the motor will deliver enough force at the correct frequency to achieve the desired results for the specific process being performed.
A motor capable of delivering large amounts of force at the wrong frequency will not produce effective motion of the material being processed, no matter how impressive the specifications of the motor may appear.
The Frequency Range Will Help Define Which Motor is Best
Most industrial applications rely on some type of vibration between 1800 and 3600 vibrations per minute. However, the optimal frequency range for a given application depends primarily on the characteristics of the material being processed or settled. Generally speaking, materials with coarse particle size respond more favorably to lower frequencies with greater amplitude. Conversely, materials with fine particle size require higher frequencies with lower amplitude. Some motors have adjustable frequency ranges, which may appear advantageous until it is realized that most applications define their optimal frequency early in the life of the motor and never change it.
Duty Cycles Give a Better Representation
Duty cycles give a more realistic representation of motor capability than peak performance ratings. A motor designed for continuous duty can run continuously without overheating and premature wear. Intermitent duty motors are less expensive initially, but are not built for long term, prolonged operating periods. For operations running 2 or 3 shifts daily, the differences in cost between intermittent duty motors and continuous duty motors will become evident after several months.
Reality Check of Installation
When the electrical specifications of a motor appear straightforward, the fact of the matter is that single-phase motors function adequately for smaller applications or areas where 3-phase power is not available. Single-phase motors are typically less expensive and are easier to install. However, 3-phase motors are much more efficient and can accommodate much larger loads; but they must be installed correctly. Additionally, the voltage requirements for the motor must be compatible with the existing electrical infrastructure. Purchasing a motor that is rated for 480V for a location that is wired for 240V is a very expensive mistake.
Mounting Options Vary Much More Than Most Suppliers Allow On
Foot-mounted motors operate satisfactorily when a solid surface exists to bolt the motor to. Flanged mounted motors are used for applications requiring direct attachment to the surface of the equipment. There are also applications that require resilient mounting to isolate the vibration, while there are applications that require rigid mounting for maximum force transfer. Choosing the wrong mounting option will not only adversely affect the performance of the motor, but can also damage the motor and the equipment it is attached to.
Environmental Protection Ratings
In addition to environmental concerns, the IP rating of a motor will vary depending on the intended operating environment. For example, a motor with an IP rating suitable for a clean warehouse would not last long in a dirty concrete plant or in a facility that requires frequent wash downs. While the initial cost difference between a standard and environmentally protected motor is minimal, the long-term benefits of purchasing a motor that will last, verses one that will fail due to environmental reasons, and the associated lost production time, far exceed any initial cost differential.
Total Cost Considerations – Purchasing Price vs. Long-Term Costs
Price paid for a motor is only a portion of the total cost involved. Less expensive motors that require frequent bearing replacement will ultimately cost money, not save money. The total cost will include the cost of labor to maintain the motor, the cost of replacement parts, and the lost production time associated with maintaining and repairing the motor.
Ball bearings that are specifically designed for heavy-duty service are better equipped to handle radial loads than lighter weight bearings and are generally longer lasting. Some motors use sealed bearings that do not require lubrication, while other motors require periodic lubrication. Applications that do not have a full-time maintenance person should choose sealed bearings regardless of the additional initial cost.
Accessability of the Motor is Important When Maintenance is Needed
Some motor designs require removing half of the installation to access the fundamental maintenance points. Other designs permit inspection and replacement of bearings without the motor needing to be removed from its mounting. Although this distinction may not be important when everything is new, it will become paramount at 2:00 AM when production has come to a halt and each minute counts.
Making the Right Choice
The best electric vibrator motor for any given process is a combination of meeting the requirements of the process and the realities of the process. The motor provides the necessary force and operates at the proper frequency for the material being processed. The motor operates within the limits of the power provided to it and is mounted in a manner consistent with the mounting requirements of the process. The motor is designed to operate effectively in the same environment that it will be operating in, and not in a hypothetical environment.
More importantly, the motor was purchased from a supplier that understands the requirements of the process and asked the relevant questions before recommending a motor. Companies that immediately recommend their most expensive motor without first assessing the requirements of the process are generally the wrong companies to deal with. Companies that ask questions and occasionally recommend a less expensive option are worth considering.
Selecting the correct electric vibrator motor to meet the process requirements of your application will result in a smooth operating process, reasonable maintenance costs, and no production bottlenecks. Selecting the incorrect motor will require you to address those issues.