Do you use a braking resistor?

[Wade Lippman]

I have, after a month of fussing, decided on the new VFD for my Jet 1642. However, it comes with and without a provision for braking resistor. The without is cheaper and smaller. I asked the manufacturer if I needed one. He asked a lot of questions about the machine and how I would use it, and replied "probably not".

So, those of you with VFD equipped lathes... have you tried without braking resistors and how has it worked out?

[Robert Hayward]

The VFD on my Oliver jointer has braking capabilities and if I am remembering correctly also has the option of installing a larger resistor for braking on heavier loads. During VFD set up I chose five seconds as the braking time and have never changed it. Do I need the head to stop in five seconds in my hobby shop? No, if it coasted to a stop it would still be good, but it sure is nice to have. My single phase table saw is another story though. I would love to have five second braking on that.

Not even sure if my 3520b VFD has a braking resistor or not. Do not recall thinking I needed the lathe to stop quicker like I do with the table saw. So I am guessing I do not need braking on my lathe.

[Michael Schuch]

I have Hitachi VFD on my SouthBend 13" metal lathe. I put a fair size braking resistor on it. I the only time the braking resistor is actually used is during an emergency stop via the emergency stop button. The emergency stop, stops FAST!

For normal operation I doubt you would ever need a braking resistor. I have a half dozen other machines with various VFD's, none of them have braking resistors. The table saws all stop in a couple of seconds as programmed.

[Steven Cooper2]

the drill press has a stop time of 1 second and have had no issues with it.

On the table saw, I'm at 4 seconds, and it works well with both fulll kerf blades and the dado stack. I had it at 3 but it would trip the VFD with the dado stack.

I'm also rebuilding an old GROB 18" metal bandsaw which I plan on putting a VFD, probably going to get a model with a resistor in this case. Even without though I imagine it would stop in a reasonable amount of time.

[Reed Gray]

I actually don't know. I remember with my 3520A, if I had it in the high speed range and had a sizeable bowl blank on it, it would trip the converter. I can see where it might come in handy for bigger pieces.

robo hippy

[Brice Rogers]

With a heavy piece and a braking resistor, it would probably be good to use a chuck or faceplate with a grub screw to keep the piece and chuck/faceplate from unscrewing. Don't ask me how I would know. :rolleyes:

[Neil Strong]

The VFD on my wood lathe was not meant to be programmed by the user. It came with whatever brake setting the manufacturer thought most appropriate for the motor size and swing on the lathe.

I have had the VFD enclosure open but can't recollect seeing an additional resistor attached outside of the VFD unit itself. There could have been one inside of the VFD unit itself as that is quite large in itself, but I presume that most of the braking is achieved through phase shift.

What I can say is that I rarely need to have more braking than the pre-set. Occasionally a very heavy or large diameter piece will be a bit slow to come to a stop. Of course, there is always the handwheel to grasp to provide additional braking... I wear leather gloves when turning, so a bit of friction isn't going to be an issue there. The only issue with that method is that you do have to reach through the line of fire to do that.

I did have an issue with the lathe braking too quickly when I was turning very long thin 3mm spindles that were held between chucks... the chuck on the headstock end would stop relatively quickly with the braking while the weight of the chuck in the tailstock end without braking kept spinning and the 3mm spindle would just twist apart. The solution was to turn the power off to the lathe at the wall. That way the VFD couldn't apply any phase shifting/braking and the momentum in the motor would very slowly and smoothly coast down to a stop.

[Dick Strauss]

Starting and stopping the lathe too often with a large piece can cause the VFD to heat up a fair amount. This localized heating in the VFD can shorten its lifespan. Whether a resistor is worthwhile is up to you.