VFD Pulley Setup?

Jim, I don't know what a sensorless vector is. The VFD was a christmas gift from my son. 'bout a hundred bux.
Many modern VFDs have SV mode, also sometimes called CV or something else. Basically they keep the torque constant from 0 to the motor rated speed. Increases the low speed motor performance. You normally need to set a parameter if your VFD is so equipped.
 
Our vari-speed Bridgeport was reconfigured by the machine shop that had it to remove the variable speed parts as the ratings were shot so they rebuilt with different bearings and single pulley and VFD.

works fantastic except for squat for torque on lower speeds.

Easy to select back gear but having the pulleys in place would allow proper torque increase with rpm decrease as well as variable vfd speed

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I kept the step pully on my RF30. Use a range of 30 -90 Hz on my VFD. With that range I can go from 1/2" end mill to 2" face mill in aluminum without changing belts. The only challenge I had was the motor on my mill while a genuine Marathon (from Wisconsin) motor the shaft size was non-standard for the frame. As I recall it was 1mm smaller diameter than the standard for that motor frame. Had to bore out the pully to get it onto the new motor.
 
Another vote for "keep the steps". I have vfd's and step pulleys on both my lathe and mill. A ratio that will run a 3/8" end mill will stall out on a 1" drill.

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I'm trying to program the Hz range on my VFD to go between 30 and 120 but it won't go over 50hz even though I raised the max hz. The booklet has a chart but it doesn't say what the various settings do or what effect changing them makes. I just spent an hour pushing buttons to no avail.
 
It took an hour or two of messing around with the settings to find the right combination to allow mine to go over 60hz on mine too. Keep trying it's in there!
 
Your original post question, leave the original pulleys reduction as it is now.
I have my milling machine set to the middle range. If I ran it off 60Hz 3 phase I think that setting was 1150RPM. I never have had the need to change the belt settings. I have a Hitachi VFD.
I don't think I've seen anywhere in this thread what brand and model of VFD you have. So getting help with the program parameters is not possible.

My VFD lets me display the spindle RPM, as it knows what Hz it is running the motor at, and there is a program parameter in mine that is a conversion ratio of motor shaft RPM, to spindle. It is very handy when wanting to set the SFM of a cutter like HSS to not exceed 100. I use the speed potentiometer on the VFD. It's another project to mount a remote start/stop, and speed pot. I just never get to it.
 
I finally found the info on my unit which is the YL600. I had to change 8 parameters spread over a half dozen pages and proportion them to the frequencies I wanted. Many of these had titles that made no sense to me. I would have never guessed this in a million years without help. Now I have the VFD set up for 30 to 120 hz. It's still gets a bit shaky on startup on the low end so it may need some tweaking but at least it's usable so I can install it now. My unit displays only frequency so I made up a cheatsheet in Excel to derive spindle RPM at 30-60-90-120 hz. Thanks all for the help.
 
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It just occurred to me while programming my VFD that it seems to have no shutoff. Do I have to put a switch on the input?
 
For an E stop, you really, really want the VFD dynamic brake to bring it to halt as soon as possible. Most have external control provision - just wire the run switch inline with an E stop button and you're good to go. Pop the switch, it'll being the motor to stop as soon as it can by shunting the coils through resistors. Powering off the VFD won't do this. Mine stops in about half a second, rather than lazily winding down like it would if you just switched the motor off by isolating it.
 
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