direct drive 2x72 motor question

[ss caustic]

hey guys I've been googling /searching quite a bit on this but have found mixed info.

I'm sure it's been asked or spoken of before at nauseum but I can find any definitive info.

preface:

I'm a little confused as to how the sfpm is determined ,and what is really required.

I'd be using ceramic/coated belts most often , but will also be using small contact wheels and polishing belts.

question:

basically I'm trying to determine what rpm (1725 or 3600 ) of 3ph motor to use on a direct drive 2x72.

now this will be a vfd driven motor looking at 2 hp or 3hp.

so far I've read that:

1) some guys are using a 1725 rpm with 6" drive wheel and using the vfd at 120hz to get higher speeds.

(but this would seem to me to end up burning out the motor faster)

any one have pros /cons to say about this?



2) some are using 3600 rpm with 4" drive wheel,( some say you loose torque)

is this really an issue with 2hp or 3hp motor?

any thought on this?


any and all help appreciated.

thanks

 

[Phillip Patton]

Well, no one else is speaking up yet, so I will.

I am in the process of converting my KMG to direct drive, VFD controlled. I decided to go with a 2 horse, 3450 rpm motor, since that would give me the same top speed I have now, (5416 SFPM) assuming the same drive wheel diameter, which is 6".

This thread has some good discussion:

http://www.bladeforums.com/forums/s...ox-motor-questions?highlight=direct+drive+kmg

 

[ss caustic]

thanks for the thread link, much appreciated!!