Wanting to use a VFD on my Jet GH-1340A

[jbobb1]

I have basic knowledge about VFD's, but I'm unsure if it will be used along with the current contactor or stand alone. My biggest concern is will the fwd/rev switching on the apron become obsolete? I assume using both Hi/Lo on the 2 speed motor is going to be out of the question also?

 

[mksj]

The use of a VFD on a lathe is not difficult, but requires significant wiring changes and there are a number of variations. You cannot use the contactors to switch the motor direction, the motor needs to be directly wired to the VFD, the VFD low level (usually 24VDC) inputs need to be used to give run commands to the VFD.

The current For/Rev is usually used, often this is via 2 wire control. So in a mannor they are used to switch the low level VFD signal inputs. The problem arises is that you typically need some form of relay system that prevents restart of the machine unless the spindle switch is cycled through the stop position. There is a simple single relay design that was used which can do this when used with the Hitachi WJ200 VFD (it is one of the few VFD's who's internal power supply can operate the VFD). I have attached an example below, I would have to dig through my old files to get the suggested programming parameters/notes. This is a design that has been used on various lathes. You must have an external braking resistor on the VFD when using it with a lathe, this design only works with the Hitachi WJ200.

You might also look at this post, although it prevents restart with power up, it does not prevent restart if say you hit the E-Stop and then release the E-Stop. I prefer some form of latching power relay design.

VFD'ing Around

I was not sure where to post this thread so it is here. Purpose is a little bit of documenting, bragging (can I do that?) and sharing what I learned. When I purchased my little Asian lathe (PM1340GT) I knew nothing about turning metal so I did not want anything standing between me and getting...

www.hobby-machinist.com

As far as the motor you want to only wire it up for one speed, typically this is the full Hp connection, typically the 1750 RPM (4P). But various by motor specifications.

 

[jbobb1]

Thank you for the info mksj!
I have a Automation Direct VFD that came with the lathe/mill deal I bought a few months ago. I need to do a little research on this unit because you're bringing up a lot of issues I would have never thought about.

 

[Cadillac]

I used the micro switches that were originally on my machine. Your apron handle uses two switches that controls for/rev. You will have to rewrite them but fairly easy. Idk how your manual is I installed a teco vfd and just wired the e-stop in line with the for/rev wire circuit all works as it should.