VFD for induction motor in band saw
In fact, the manufacturers of this particular band saw sells the induction motor / VFD drive as a servo axis. The customers don't know the difference but they just cannot cut straight and the saw bands don't last very long.
However, the manufacturer doesn't care very much. So one customer asked another band saw manufacturer to help. He replaced the induction motor and VFD with a real servo system and the saw works just perfect now.
Another application was a coil winding machine where a rotating flyer winds the copper wire around a winding form with 5 steps (winding a coil for a two-pole chiller stator). While winding, the winding form drops from one step to the next when the proper turn count of each step is reached. It is essential that the cross-over, the connecting wire between the individual steps, is always at the same spot.
Using induction motor and VFD, it was just not possible to do that. The cross-over wire climbed everywhere but not where I wanted it to climb. I never experienced this kind of problem with a real servo drive. Here I can put the crossover exactly wherever I want it to be.
However, the manufacturer doesn't care very much. So one customer asked another band saw manufacturer to help. He replaced the induction motor and VFD with a real servo system and the saw works just perfect now.
Another application was a coil winding machine where a rotating flyer winds the copper wire around a winding form with 5 steps (winding a coil for a two-pole chiller stator). While winding, the winding form drops from one step to the next when the proper turn count of each step is reached. It is essential that the cross-over, the connecting wire between the individual steps, is always at the same spot.
Using induction motor and VFD, it was just not possible to do that. The cross-over wire climbed everywhere but not where I wanted it to climb. I never experienced this kind of problem with a real servo drive. Here I can put the crossover exactly wherever I want it to be.
