Overload of the Motor - Automatic Door

[juangla99]

We have contract to install over 100 automatic door type LiftMaster J H HJ in a warehouse project. The doors have a long time in place and ready and but the project have not start to operate yet and some of these door stop working. The technics of the company come and diagnose that the problem is because some kind of overload of the voltage coming from the branch circuit and he recomend to change the 20A-1P breaker of each automatic door. This have sense?

Actually almost all the motor present damages in the incoming side of the internal transformer of the equipment. Now the technic is recomending to incorporate a voltage regulator in each of the automatic door, explaining that the problem of the transformer is because fluctuation of the voltage, or peak from failure of the lines. A transformer in this kind of door could be damage even if the are not in use (their feeding breaker are ON).

I have the idea that the problem could come from the low use and weak maintenance that force the system but the technician said that this is almost impossible.

Second Question. How to deal with this kind of explanation that the problem is because of some unexpected over voltage situtation, when you see that the technician does not come even with a multimeter to check the problem. (note that these situation are not cover by the warranty!!!)

Thanks for advices and comments.

 

[starbolin]

Over-voltage would, possibly, damage the motors or motor controls but this would need to be verified by a recorder on the supply voltage. Replacing the breakers would have no effect on an over-voltage situation. If the technician is claiming that breakers are not protecting his motors from burnout then a simple solution is to test the breakers to verify that they trip on an over-current condition.

Another test to be done is whether the motors draw more current than the 20A circuit design rating when the motors are stalled as from a door not opening. Your vendor might not like the results of that test.