Every shop has experienced it – a process grinds to a halt because a coil, or solenoid, has burned out. As with all industrial components, failure is a matter of when, not if. But there are plenty of ways to maximize the life of these coils. The key is to recognizing what conditions cause one to go out prematurely.
Here’s a quick rundown of the why:
Solenoid Fail Point 1: Electrical Supply
Generally, the most obvious reason for a solenoid to burn out is to mis-apply the electrical supply. Coils which use Alternating Current (AC) require both proper voltage and frequency to operate. Direct Current (DC) coils must receive the proper voltage level. Typically, staying within a +/-10% of a solenoid’s rating will keep you in business.
Beyond that, things get a little tricker.
Fail Point 2: Temperature
Extreme temperatures are never a good thing for you – and a coil feels the same way. Temperature beyond what it is rated for can drastically shorten service life.
An induced ambient temperature above the rating will degrade the insulation between the winding, and cause shorts. Rapidly cycling a solenoid on and off keeps it from dissipating heat caused by inrush current. Inrush current occurs during initial energizing and draws current up to five times the rating as the coil is pulled in. This can also be seen for extended periods of time if there are issues keeping the valve from shifting completely.
However you slice it, if you are keeping the temperature at extremes, you will see premature failure.
Fail Point 3: Contamination
Contamination by sea water was the cause of failure in the solenoid pictured at the top of this post.
If the operating fluid becomes contaminated, that can lodge in the spool and body, or cause rust to form. When this happens, a high current condition can become extended, which will cause overheating and failure. Contamination can also cause a valve to fail to shift completely, which would hold both coils on a double solenoid valve as energized simultaneously. In this case, the first energized coil will fight the second coil, causing current to rise.
These are just a few common reasons you can find if you are suffering from solenoid burnout. If you are having this issue at your plant, contact Kaman Fluid Power’s expert staff. We can investigate for these, or any other issues causing part failure, and find solutions that can save you money and reduce downtime.
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