I have a friend who is adamantly against putting VFDs on old machines like lathes and mills and whatnot.
It came up while I was showing him the progress of my FP2 renovation and while going over the electrical cabinet I mentioned a lot of people replace this with a VFD instead to get various features like being able to adjust speeds between gears even more finely, and to quickly stop and reverse the spindle for tapping procedures. I don't have need of that for my FP2 though I could see the use for one on my lathe to be able to stop the spindle quickly for threading to a shoulder perhaps.
Well he said that's a really bad idea, that his father (retired electrical engineer) has told him that VFDs puts more strain on the motor and that the square wave they produce are bad for the motor and often lead to the motors windings risk burning out.
That motors need to be designed for use with a VFD to begin with, and that especially older motors like in "old iron" machinery are susceptible to being destroyed if tried to run with a VFD. He was deeply critical of what he thought was the "modern trend of everyone and their dog mounting a VFDs on their machines".
I should add we're not located in america but in Finland and 3-phase is standard residential power here so nobody needs a VFD to make an old industrial machine run in ones garage.
I dunno, I have never heard of people burning out their motors on VFDs except when they try and run a motor too slow, then it tends to heat up and the fan also can no longer provide adequate cooling in those cases. I am somewhat skeptical of his claims but he does have someone who used to work a place that built induction motors.
What do you guys think?
It came up while I was showing him the progress of my FP2 renovation and while going over the electrical cabinet I mentioned a lot of people replace this with a VFD instead to get various features like being able to adjust speeds between gears even more finely, and to quickly stop and reverse the spindle for tapping procedures. I don't have need of that for my FP2 though I could see the use for one on my lathe to be able to stop the spindle quickly for threading to a shoulder perhaps.
Well he said that's a really bad idea, that his father (retired electrical engineer) has told him that VFDs puts more strain on the motor and that the square wave they produce are bad for the motor and often lead to the motors windings risk burning out.
That motors need to be designed for use with a VFD to begin with, and that especially older motors like in "old iron" machinery are susceptible to being destroyed if tried to run with a VFD. He was deeply critical of what he thought was the "modern trend of everyone and their dog mounting a VFDs on their machines".
I should add we're not located in america but in Finland and 3-phase is standard residential power here so nobody needs a VFD to make an old industrial machine run in ones garage.
I dunno, I have never heard of people burning out their motors on VFDs except when they try and run a motor too slow, then it tends to heat up and the fan also can no longer provide adequate cooling in those cases. I am somewhat skeptical of his claims but he does have someone who used to work a place that built induction motors.
What do you guys think?