# VFD mounted on a lathe ...



## precisionworks (Jan 3, 2010)

Just saw this on the PM website:

















Full writeup here: http://www.practicalmachinist.com/vb/showthread.php/vfd-setup-remote-12-195492.html


----------



## wquiles (Jan 3, 2010)

Very nice installation 

I hope to do my own soon


----------



## cmacclel (Jan 4, 2010)

Super Nice install but why go through all that to install a underrated VFD for the job? The correct VFD is only $100 or so more.

Mac


----------



## precisionworks (Jan 4, 2010)

> why go through all that to install a underrated VFD ... The correct VFD is only $100 or so more.


The model he used costs $299: http://www.factorymation.com/s.nl;j...749.e3eTaxiNaN0Te34Pa38Ta38Lbhr0?it=A&id=5578

The next step up is a 7.50 hp (derated to 3.75hp for 1ph input) ... still too small for a 4hp motor.

The "correct" drive is the 10hp version (derated to 5hp for 1ph input), but the cost is $550. http://www.factorymation.com/s.nl;j...749.e3eTaxiNaN0Te34Pa38Ta38Lbhr0?it=A&id=5567

The choice is to use a 3hp drive, knowing that the motor will trip the drive under heavy load, or pay another $251 for the drive best suited for the application. If the lathe mostly does smaller & lighter turning & boring, the 3hp drive should be adequate.

VFD's for 1ph input are pretty inexpensive at 3hp or less. Above that, the price climbs quickly.


----------



## wquiles (Jan 4, 2010)

Since the NEMA1 is $522 and the NEMA4 is $811, one of the options I am considering for the 10HP Vector Drive that I need for my 5HP conversion is to get the NEMA 1 enclosure and build a box/shield as he did, on the back of the lathe, hidden away from all debris/coolant, but with the cooling slots and metal mesh to prevent "stuff" from getting inside the enclosure.

Worth doing, or just keep saving for the NEMA4 version?

Will


----------



## precisionworks (Jan 4, 2010)

> get the NEMA 1 enclosure and build a box/shield


That's a good option, especially since you already know how to wire the remote Fwd-Stop-Rev switch and the speed pot. 



> with the cooling slots and metal mesh


If you use an enclosure that has 4X the volume of the drive itself, radiant cooling will take care of all VFD heat. 

The 10hp SMVector drive (NEMA-1) is 5.2x9.8x6.3 (inches) = 321 cubic inches. An enclosure with a volume of 1284 cubic inches needs no vent holes or cooling slots. A box measuring 10x10x13 (inches) would be the minimum volume size, although any combination of dimensions that yields 1284 cubic inches, or more, will be fine.



> Worth doing


Without a doubt, to save almost $300 :thumbsup:


----------

