Treadmill motor on rong fu rf-30.

[RJSakowski]

Another possible avenue for a dc motor is a digital system. The difference between a commanded speed and actual could fairly easily be programed to increase pulse width or voltage to maintain the commanded speed. . I would still use an encoder to monitor speed.

 

[Bruce Billett]

I have one of these mills The belt change is a bother. So I found a couple of treadmills people were throwing/giving away. Mostly the belt seems to have failed and they didn't want to bother with replacing? I pulled the motor and controller from the treadmills and used the them to repower my mill. Added a tach to the system and it has been great! I don't know how much ACTUAL HP it has but the motor is rated at 2.5 HP. The whole belt drive I struggled with but found that if I used the existing J belt .25" wide it would fit into the V belt pully well. Ain't perfect but it works. I now have a lathe and I expect I will turn down my existing V pully to the J belt one of these days. More for grins than anything else. Mounted a control box on the back base of the mill to hold the controller. Speed control consists of a remote 10k pot and a 2 position toggle switch for start/stop in a small plastic laser scanner box I salvaged. My Tach readout is next to it in a small plastic kit box. I have (according to my Tach.) very good control down to about 10RPM or so up to around 2K. Machine gets flaky (machine vibration) much above about 1500 RPM. But then what do you expect for a rf30 mill. Also never go there except to see what would happen, DON'T!
I have had no issues with torque other than at first when I hadn't gotten the belt tight enough. Biggest issues I had was figuring out the existing electronic drive, but in truth I like trying to figure out how to make something it wasn't designed for work for me. I tried a few of the after market PWM systems and what not, but never got the performance I wanted. If it ain't broke, don't fix it! Controls are just a bit bulky but I got the room. Found a scrap 4"X6"X10" metal box for the controller added a fan from an old computer and it has been working great.
I use a Hall effect sensor for my tach. No feedback.

b

 

[Hawkeye]

I have a lathe and an RF-30 running off the same VFD (switchable) and a drill press on a second VFD. My X2 CNC mill (much smaller) is run by a treadmill motor with a PWM module. Also a belt grinder that runs well on a treadmill motor. Treadmill motors run at a higher RPM than induction motors. Not bad for small diameter endmills or grinders, but not good for heavier cuts or larger diameter tools.

I heartily recommend 3-phase motors and VFDs for machines that size.

 

[Bruce Billett]

I suppose I would have to agree with this. I have NO experience with heavy tools and would think the little treadmill motor would not do the job. On my RJ it's been no issue.
The whole 3 phase thing is an issue, I can get it, but the cost is WAY high for install. Getting a converter? I have a friend that ran into this and got a converter but found that the efficacy of the converter was horrible. However there certainly are some good cases for doing this. After all the tool set was designed for 3 phase for a reason

 

[mattthemuppet2]

If you can get the dc motor and controller for free it’s a great option. I have tm motors on my lathe, drill press and 6x26 knee mill and they’re great. Belt and countershaft system varies but the only time I’ve struggled on the mill is with large (3/4”+) drills in steel as it can trip the overcurrent protection on the board. Upping the controller board would help with that, as would using an intermediate pulley, but it’s not something I do often enough to worry about.

If you’re buying a motor and controller, then 3ph + vfd would be the way to go.

 

[Bruce Billett]

I have also found uses for other parts from a treadmill. Structural components are good for building things, the rollers make good stock handling for shelves etc. The belt Or parts of it are good for all sorts of stuff, chip shields, splash guards, tool box and work bench top cover. Getting the electronics to work can be a bit of an issue, but a day or so of futzing around and you will get it.
Haven't done it yet but I'm working on using the ramp lift to build an X table feed as per the latest home shop machinist mag. Going to replace the 120V motor with a DC motor. Not a blind drop in but it looks doable.
In the end FREE is a very good price!!

 

[Hawkeye]

I'm thinking you missed out on the often unspoken part of 3-phase. Most of us who use it have inverters that run on single phase power. If you connect them to 240 volt 1ph, they output 240 volt 3ph, with the smoothest speed control and a few other control advantages. Soft start, reverse, etc.

 

[Bruce Billett]

You are correct, I did miss that one.
My friend did not have that good fortune, Haven't seen him in a while, perhaps he has improved his situation?

 

[animal12]

Either of you guys interested in selling the intermediate pulley yer not using anymore ?
thanks
animal

 

[Bruce Billett]

I fear not. I am still using mine. I don't need it for the gear reduction or anything like that. It is more a matter of there is no direct path between the motor and spindle pully otherwise.
I do however still have the pully off of the motor itself? Most likely won't help you, but it's there
b