r2e4 varispeed with retrofit.

[najnielkp]

hi all,

i have a r2e4 and am about to retrofit to mach 3 with rutex 2040 drives. i have a question about the varispeed spindle control. i have read from others that they used a vfd for speed control. can the varispeed be integrated into the retrofit? is the air motor controlled via pwm to the solenoid valve?

[Mickey_D]

Most of the breakout boards will allow you to send a signal to the vfd that mach 3 generates for starting and stopping the spindle motor. Using the vfd to vary the spindle speed is a little iffy, if you go much over stock you will eat your motor bearings and varispeed drive. If you drive the motor below 50% it will not get enough air flow and the motor will over heat. The VFD is great for "tweaking" you spindle speed, but you can kill your motor if you are not careful.

[najnielkp]

thanks for your reply.i am going to install a led tach on the front panel to set speed,and use the existing contactors.

[colin1544]

Hello I read your comments with interest you say that using the motor below 50% would likely to cause burnout this all depends on the loading you are putting on the cutter I have been using a VFD on a series I CNC and had some problems on the system tripping out but I finnished up checking the loading and it was all down to the settings of the VFD I have run mine for full daily shifts on mid duty loads and the current drawn varies between 3.9 amps & 4.5 amps this is running speeds at between 750 - 1500 rpm on various cutters and drills using programmable spindle speed selection and it produces bearly any heat on the motor casing to the touch the percentage equates to 20 - 60% I have fixed my vari speed pulleys to give a maximum 3000 rpm doing this has quiten the spindle down and the only rattle I get is between the clutch dogs on the high low range sleeves it is definetly an improvement on the origonal system . Cheers Colin1544

[jeep534]

I too have a R2E4 and will most probably retrofit it with mach 3. I understand the problem. the motor speed. the speed of the Varidrive which is controlled by an air motor.

First off I would set the parimeters of the VFD to go no lower than about 50 percent and no higher than about 110 percent, hardwire a potentiometer and a switch (SPDT center off) then hardwire a raise and lower buttom feeding the air selonoids.(SPDT center off Momentary contact switch) I would put a pointer coming out the cover on the front of the head to show where the vari drive is setting. and fit the spindle with a tach.then feed that back into mach.

at that point you would have a speed knob, on/off,direction switch for the VFD and a switch to raise and lower the varidrive, a mechenical speed representation for the vari drive, a visual representation for speed and direction on the vfd and a tach feedback to mach,
If I am understanding my mill correctly there is no automatic speed control on it currently. you have to run the speed up and down manually with a button. the spindle will start and under program control however
that leaves one with 3 things to control/monitor for speed of the spindle. backgear,motor rpm,varidrive setting


when the time comes that is what i intend to do.
just my 2 cents.
I am very interested in your retrofit
maybe even some of your takeoff parts to keep my mill running as it set's now.

I have had the mill for about 3 week and I am still trying to get it up and running.
I was able to jog it yesterday so all the axesis work but sme of the buttons on the control pannel don't ( 10 to be exact)

so keep us posted on your progress. I am monitoring the Mach group on yahoo as well.
Good luck
archie =) =) =)

[jeep534]

I almost forgot I would think that after all is said and done you could interface the vfd with mach for start/stop and direction maybe even speed within certin parameters but leave the vari drive manual control. either way you would not want mach to exicute moves in the program until it sensed that the spindle was turning.

Happy Hunting
archie =) =) =)