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Belt grinder set up

Discussion in 'Grinders' started by alanf, Jan 27, 2014.

  1. alanf

    alanf New Member

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    Hello, I am building a KMG clone 2x72. Power is 2hp 3ph 3500rpm Baldor motor and controlled by a KBAC27d frequency drive. I have made up a 6" diameter drive wheel. Belt speed at 3500rpm works out to 5,495sfpm. I am looking for advice on how to connect the motor to drive wheel. As I understand it with a frequency drive, when you slow motor down or overspeed it, you lose torque. Should I run 1:1 out of motor or should I "gear up" or "gear down" going from motor to drive wheel? If I go out 1:1 I wonder if a lovejoy coupling might be a nice way to go about it?
  2. dancom

    dancom Dust Maker Legend Member

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    I saw this post for the first time today. Have you found a way to connect the motor & drive wheel?

    I would program the drive to run from about 20Hz to 80Hz. The typical VFD/NEMA motor torque curves would show full torque at low speeds and a drop off to about 75% at 90Hz. The unknown is how the bearings and rotor like being run at higher speeds. Anecdotal evidence suggests most well built 2 pole motors can handle 80Hz for years, and people are running 4 pole motors at 120Hz.

    With the large diameter drive wheel and VFD, putting the wheel directly on the motor shaft is the way to go. Drive wheel and shaft should be keyed and set screwed. Generally the less moving parts the better.

    I am doing something similar with a 2 horse WEG on a VFD.


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