boss 5 vfd with timing pulleys

[jamescrowe]

i am in the process of retrofiting my series 1 r2c3 and would like to convert the drive to a vfd with timing pulleys. i have read all the post that i could find concerning this topic and would like to run my proposed set up by you guys to get some input/feed back. the motor is a 2 hp using a sensorless vector drive, i did the rough math using a 1:1 pulley set up and came up with72rpm@20hz-590rpm@160hz in back gear and 600rpm-4900 rpm in hi, what is the workable range of the hz without loosing tons of low end and not over speeding the motor, i know that i will not ever have the perfect senario but do not want to loose too much on the bottom end. assuming that i will need to machine a wide range of material, still drill large hole and tapping ,what do you guys recommend for ratios, or am i asking to much from the set up. i was also woundering if anyone has alternatives to timing pulleys, i saw someone with a flat ribbed belt set up but cannot refind the post, i herd the timing pulleys can make some noise.
any input/sugestions would be very much apreciated
thanks
james

[colin1544]

Hello James I share your interest in this as at the moment I have a VFD driving mine which at the moment I have fixed the origonal vari-speed pulley and belt using a spacer and similar to you I am running at a 1 - 1 ratio, my set up at the moment is that I have the drive set at an output of 60 hz and I'm only using 100% giving a maximum speed of about 3000 RPM. Your Idea about timing belts is probably true I am eventually going to replace mine with Poly-vee belt drive using the 2.35 pitch of vee's as these give a smoother running spindle and will run alot faster than timing belts, you can also make your own pulleys up to suit. Running at 1-1 the bottom end torque in open gear is a bit limited, so it might need some experimentation with ratio's. I will be interested in your findings. Cheers Colin.

[jamescrowe]

hey colin
i remember reading an old post of yours about vfd's, what brand did you end up going with? the set up i am using is a centroid m-40 controller and want to be able to control spindle speed with the controler. i found the post i was looking for and the set up that really looks nice is what maclec54 did with the polyVbelt, has anyone else done something similar?
i was also curious if anyone has information about setting up their centroid to run off a vfd?
thanks
james

[jamescrowe]

is there any difference between a polyvbelt and an automotive serpentine belt? you could adapt some automotive pulleys if you made the hubs. how wide of a belt do you think you would need to run?
james

[colin1544]

Hello again James I am not sure about the differences between polyvee and auto motive belts but I should imagine they are similar, I would think you would need about a minimum 1" width, if you compare the later Bridgeport interact 1 Mk2 they have polyvee belts about 1 1/2" wide and a 6HP DC motor driving the spindle, just to give you some comparison. Cheers Colin