Anyone whose job involves servicing electric motors has encountered the problem of a missing nameplate. Other articles in the Motor Doctor series have covered ways of determining the specifications of a motor lacking the nameplate, but what if you are trying to figure out how to wire that motor?
A critical element of motor servicing technique is being able to determine whether or not a replacement motor that is not an exact duplicate of the original is suitable for the application. As a technician, you must consider a number of factors, but this article focuses on one of the more important issues: nameplate amps.
How often do you encounter this problem in the field? The motor
in question continually nuisance trips. You look at the motor and the application:
the motor appears to be running properly; the driven load is working properly;
and yet the motor seems to keep overheating and tripping.
When it comes to assuring that a motor provides consistent service for the longest time possible, it’s important to pay attention to the bearing system. Bearing system failures are one of the most common mechanical breakdowns in the field.
Dealing with a user’s complaint of a noisy motor can be a frustrating experience. After all, the perception of noise is extremely subjective (just ask the parents of teenagers). Not only does the range of human hearing differ considerably among people, but it also varies by specific frequency.
When you energize a motor, you get two
outputs: a desirable one (work) and one that is not so desirable (heat).
Equipped with this knowledge, you can understand why one of the
criteria you must consider when selecting a motor for an application is the
effect of operating temperatures on that motor.
When choosing a replacement motor, you can often use the motor's nameplate to help you in making the selection, but a nameplate doesn't always provide you with everything you need to know.
Motor efficiency remains one of the top issues in our industry, but when you talk about efficiency, often you're talking about trade-offs. The Motor Doctor explains all the factors involved.