# G1008 Knee Mill...  Thinking Vfd.  Motor Suggestions Anyone???



## Dman1114 (Apr 5, 2016)

Hello....

So i think I'm going to change the motor on my mill to a 3 phase with a VFD.

I have a GS3 on my lathe with a leason motor and its been great.  I do change gears occasionally with the lathe when needed.


I really like how the G078 has it so there is no belt changes.   wondering if they use an inverter duty motor???


Looking for suggestions on Motors...   right now mine has a 1 hp single phase motor on it.

Heres a pic of the mill....


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## CraigB1960 (Apr 5, 2016)

Any 3-phase motor with the same NEMA frame so it will fit right in.  You can get an inverter duty motor, but not really necessary IMO.  Lot's of old 1-HP J-series Step pulley Bridgeports (mine included) working just fine on a VFD.

When selecting a VFD, be sure to go with a 2HP rating and have V/Hz and Sensorless Vector. 

Not familiar with Grizzly,  but on mine, I keep the belt on the second to the highest speed and use the VFD to control speed.  Due to the age of my motor, I only go slower, never above 60HZ.  On a new(er) motor,  I would not hesitate to go 100 - 120HZ.  Lot's of flexibility.

I've not had any issue running slower, but if I need the torque, I drop it into backgear and reverse the motor.  In extreme condition, I would just put the belt on the slowest speed, put in backgear, and than really be able to slow down the spindle using the VFD...just never had to.


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## wrmiller (Apr 5, 2016)

Pretty much what Craig said.  :+1:


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## Dman1114 (Apr 5, 2016)

Well the Leeson has Done me well for a good year now on my Lathe ,  I leave the gear train at 1000 rpm all the time,unless I'm threading.  then i change the gearing to 90.    i use the Pot to changer actual Rpms..... No issues at all.  ....   Maybe ill just go with one of them...

Back when i did my lathe i don't remember so many metric motors  on the market....  i have plenty of choices now it seems.  Leeson, marathon, baldor....   I have to stay with a 1hp to keep the 19mm shaft.  Anything bigger jumps up to a 24mm shaft.

But at the 148$ Price tag on that leeson  Im leaning that way.   Guess i knew the answer all along LOL  


I think its gonna be the Leeson and the GS3 with this machine


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## CraigB1960 (Apr 5, 2016)

Dman1114 said:


> But at the 148$ Price tag on that leeson  Im leaning that way.   Guess i knew the answer all along LOL
> 
> 
> I think its gonna be the Leeson and the GS3 with this machine



IEC frame instead of NEMA frame...not use to metric machines!

The $148 price tag for the motor is good and the GS3 seems like a quality VFD and has Sensorless Vector, which is excellent.   Cannot go wrong!


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