The repair for each of these three motors ran into the hundreds of thousands of dollars. In industrial applications, perfect voltage conditions are rare. Losses, not current levels alone, are the true source of heat.
These losses are a destructive factor to windings and a significant reason for bearing damage. This justifies the need for accurate knowledge of operating load level. Only accurate load level calculations can give reliable measurements of excessive losses and overheating in the motor. Power condition Electric motors in manufacturing plants generally need to be derated because of poor power conditions in order to maximize their useful life.
According to the derating curve, the higher the level of unbalance, the lower the acceptable level of steady state load. For example, if a hp motor has an unbalance factor of 3 percent, the motor should be derated to 0. The frequent use of variable frequency drives VFDs can result in detrimental effects to electric motors because of the condition of power in manufacturing facilities.
Severe distortions are evident. This scenario shows a NEMA derating of 0. Effective service factor T he key to finding the most frequent causes of overheating is accuracy in estimating load level. This can be identified by looking at only currents and voltages. The formula for calculating effective service factor is:. Effective service factor provides predictive maintenance professionals a solid conclusion of stress on any particular motor load application.
In another example, data gathered using a dynamometer showed a hp motor under test was running a nearly full load, Voltage distortion was poor due to a previously unidentified silicon controller rectifier defect in the power supply. The resulting NEMA derating factor of 0. Regardless of nameplate service factor, any motor operating above 1. Poor voltage conditions are frequent and can be caused by a variety of reasons.
Finally, as stated before, check that the motor you are using is properly sized for the application. A motor that is too small will not be able to dissipate heat quickly enough, causing it to overheat.
This seems simple, but we know that changes are made in the design process, and upgrading the motor size can be an overlooked step. This has been a Groschopp Tech Tip. For more information about any of our products or to view other Tech Tips please visit us online at www. In this video we discuss how to select a gear motor in four simple steps by choosing an integrated gear motor.
This video continues our discussion of selecting a gear motor by pairing the separate components. Now we look at how to select a motor based on the reducer selected for the application. In this video we begin our deep dive into gear motor selection. There are two methods for pairing motors and reducers to create the optimal gear motor. Here we begin with the first method by taking a look at gear box selection.
This video covers the important application criteria that need to be considered when selecting a gear motor. Right Angle reducers are great for applications where size and space are at a premium. With the ability of the the output to turn a 90 degree corner. Planetary reducers are ideal for applications requiring high torque in a small package and an output shaft with coaxial alignment.
We'll discuss the construction, characteristics, advantages and disadvantages of Planetary gearboxes. Parallel shaft gearboxes are an ideal solution for continuous duty applications; applications requiring low torque; applications with higher ambient temperatures; or applications that are cost conscious.
In this video we discuss planetary gearboxes. Learn the ins and outs of how these reducers work as well as their advantages and disadvantages. As we round out this video series, we will share several motor calculation formulas and other tools to help you with the selection process. In this video we discuss the construction, characteristics, advantages and disadvantages of BLDC Motors.
We'll also look at the BLDC motor performance curves for speed, torque and efficiency. In this video we discuss the construction, characteristics, advantages and disadvantages of AC Motors. We'll also look at the AC motor performance curves for speed, torque and efficiency. In this video we discuss the construction, characteristics, advantages and disadvantages of DC Motors.
We'll also look at the DC motor performance curves for speed, torque and efficiency. In this video we discuss the construction, characteristics, advantages and disadvantages of Universal Motors. We'll also look at the Universal Motor performance curves for speed, torque and efficiency.
This is part two of our discussion on application criteria. It seems obvious, but we like to remind our customers to always consider the maximum size and weight of motor their application will allow, and to know what kind of life expectancy the motor will need to have.
This video and the next cover important application criteria, first we'll focus on application constraints that need to be taken into consideration during the design process. Associated problems include clogged ducts and high ambient temperature.
How to help motors keep their cool One way to keep your motors cool is by reducing the excessive load that the motor handles. Testing the motor as part of a routine maintenance program also reduces the possibility of failure due to excessive heat. Use the appropriate testing methods to find hot spots within the motor windings. Ensure that your motors have the proper protection in place.
That protection includes thermostats and overload protectors. One piece of a good maintenance plan, these devices ensure that the motor is not operating at damaging temperatures. Electrical motors are often some of the most expensive assets in your facility.
With proper maintenance and common sense, extending their useful lifespan becomes a little easier. Yale Materials Handling Corporation. Beckhoff Automation LLC. ABB Power Conversion. By using this website, you agree to our use of cookies. This may include personalization of content and ads, and traffic analytics.
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