Centroid Community CNC Support Forum

VFD is working and connected to BP 2hp motor.
Problem:
when i m3 s500 motor will run slow estimated 150 rpm or less. s750 spindle will run a bit faster, s2000 spindle is running fast.
I have the max spindle speed set at 2000. If i set max spindle to 1000, then s1000 is max speed.How do i scale the rpm to be more accurate, seems as if i set the s command to less than 500 there is not enough command through vfd to turn the motor unless i set max rpm to 1000.

How do i scale the 0-10 v to high range vfd? Maybe it is unrealistic to run a spindle @ 500 rpm in high gear.

I still need to pin the tilt plate varible drive up in rpm a little, its not at 1:1 ratio currently. On tilt plate pin subject, it has an air driven speedup / slow down motor. what is the method used to tension the chain and pin in place with an air motor? if it just had a hand crank that would be simple.

Please advise.

Maybe a silly question but is your spindle encoder driven at 1:1 from the spindle itself & not from the motor output shaft? It has to be that way to work properly.

Spindle speed scaling is done on the VFD. There should be parameters that you can set to scale the lower/upper frequency with the analog input.

tblough and marty are on the right track for what I need to accomplish.
? to marty's post, my motor is a standard 2hp BP motor rated at 60hz. Am i correct in setting the vfd max frequency to 120hz?
Just don't want to cook my spindle motor.

I am using a Teco 7300 vfd
Thanks
RL

Pretty much every 1800 rpm motor can be safely run at 120Hz. Most motor manufacturers make 1800 and 3600 rpm versions of each motor and they differ only in the windings. Rarely do you run across a motor with different bearings in the slower speed motor, but it does happen.

Sometimes the insulation in older motors breaks down at the higher frequencies, but you really can't tell until you try it. If it does happen, it's usually not that expensive to get them rewound and the magnet wire the shops use nowadays will have no problem with VFD frequencies..

Thanks tblough,
Good information for all on this forum.
I have the motor setup parameters set to 60hz
I have the parameters for high and low hz set 100hz / 10hz.
I don't have a tach but running at near 100hz it's really spinning the spindle i would guess 3000plus rpm.
At 10hz load its probably ~150 - 200rpm.
Being that i set the low to 10 hz, it wont spin any slower no matter how low I set the S command.
@ this point the scaling is still not quiet correct but without a hand held tach or spindle encoder i will live with it until i get a tachometer.

Thanks!!
RL

Frequency and RPM are linear. If the nameplate is 1800rpm at 60Hz, then 100Hz should be 100/60 * 1800 = 3000rpm. 10Hz would be 10/60 *1800 = 300 RPM. You could also set the VFD minimum to 0Hz and then control the minimum RPM from the Centroid setup control screen with the min/max spindle RPM settings.