Closed Loop in the vernacular of motor speed control involves the verification of the motor’s actual speed back to the drive, for automatic adjustment to maintain constant speed under changing motor load, ambient and drive supply voltage conditions. Phew! So what is the big deal about closed loop?
There are many applications where speed accuracy and repeatability are critical to the product being produced. Even a few seconds variation in bake time of a pizza can alter the finished product. The same is true for silk-screened product being dried; salt on pretzels or sugar on donuts; parts being coated / painted / heat treated.