New Jet mini speed control

After a week without an answer, I wonder: Plonked again? Asked a wrong or boring question? Nobody cares? Nobody knows yet? Very few of our lathes are turned by waterfalls, gasoline, steam, wind, fusion of atomic nuclei, perpetual motion or even an arm or a leg. ;) There are many types of small electric motors and many ways to control and vary their speed. All of us use electric motors, and knowing a little bit about them might be helpful to someone, especially as recent lathes sport electronic variable speed control. The advent of variable reluctance methods has changed some of our notions about methods used to vary motor speed. I started to post a primer re these methods, but quickly realized it would be far OT, plus an arrogance to think I could simplify something that I know little about. Hence my simple question about the mini-jet's type of motor and speed control. Arch

Fortiter,

I don't know about the jet in particular but many of the low HP variable speed motors were actually universal motors with a "voltage regulator" to control the speed. I believe the carbatec lathe has this system. This system does not work on AC induction motors. The electronic system uses a frequency controller and a 3 phase motor. This is what my Oneway has A third system is present on the NOVA DVR.

Greg Kulibert wrote: I don't know about the jet in particular but many of the low HP variable speed motors were actually universal motors with a "voltage regulator" to control the speed. (clip) ^^^^^^^^^^^^^ I have not seen the new Jet minilathe, but I will make the following comment . If, by "voltage regulator," you mean a variable voltage power supply, I would bet dollars to doughnuts that's not what they do. More likely, they use the type of control that is commonly used to control the speed of routers: a solid-state circuit cuts down the width of the AC sine wave, to reduce the on-time per cycle, without reducing the torque. Many of them also use a feedback loop to sense any speed reduction, and correct it. These are not expensive, and they produce good torque throughout the speed range.

Variable frequency three-phase systems are quite expensive, and would not be appropriate on a mini-lathe.