Our records reveal that the number one cause for actuator failure is motor damage due to these two mistakes:
If you find your actuator lifeless despite repeated attempts to power it, you may want to bring your nose close to the motor for a quick sniff. Burnt smell is a common sign of motor damage. This smell is not similar to slightly burnt meat or a campfire, it is an unnatural smell that is common with burnt electronics. If this is what your motor smells like, it is very likely it is beyond recovery. Fear not, however, give us a call and our engineers will get you fixed up!
The easiest way to prevent this is to simply make sure that there are no obstructions to the actuator’s travel path and you are working within the actuator’s rated load. This article will discuss how a fuse matches up against a current sensor to prevent permanent damage to your actuator should these mistakes occur.
The fuse is the most common electronic safety device, but will it keep your actuator from burning out? The simple answer is… probably not. The problem with fuses is that it requires an excessive amount of current before it blows.
Here is an example of a Resettable Circuit Breaker’s operation characteristics, which is less sensitive than regular fuses but you will notice the trend is very similar. As you can see, the breaker will not blow unless you have a really large current spike or a prolonged current draw. This is great for detecting short circuits, which is why our control boxes are equipped with fuses.
Actuators, on the other hand, are likely to burn out before drawing the current required to blow the breaker. Here is a Current vs Load graph of our PA-14 Mini Linear Actuator. One would assume that a high force would yield a high force, following the linearity of the trend. In actuality, obstructions and largely excessive forces will simply prevent the actuator from moving and will cause the actuator to draw about 100% of the rated current, thus never blowing the breaker. The actuator will continue to draw power and develop heat until the motor windings burn out and break the electrical connection. At this point, the actuator will produce the previously mentioned burnt smell.
Why might one use a fuse to protect the actuator you may ask? Two words, cheap and simple. An automotive fuse blade type fuse with a small holder can be purchased for a few bucks and can be spliced onto almost any electrical circuit. It is tricky trying to get the correct fuse rating to ensure that it blows before your actuator does. This requires familiarity with the actuator’s current characteristics (can be found on our website) and intimate knowledge of your application’s current demands. There are lots of fuse ratings and fuse styles including fast-blow fuses. This makes it easier to conduct the trial and error testing if you so desire.