# Running Lathe With Vfd: Reversing Switch Possible?



## cazclocker (Jul 11, 2015)

I'm running 240VAC into my VFD, and then into the motor which is a 3-phase. Where is the most logical place to create a reverse-direction option? Is that one of the options on my VFD, or do I need to install a switch between the 240VAC wall source and the VFD?


----------



## JimDawson (Jul 11, 2015)

The VFD will do all of the reversing functions using the VFD control wiring.  Look in the user manual for the proper wiring.  Installing a switch between the VFD and the wall would have no effect on the motor direction.


----------



## cazclocker (Jul 11, 2015)

JimDawson said:


> The VFD will do all of the reversing functions using the VFD control wiring.  Look in the user manual for the proper wiring.  Installing a switch between the VFD and the wall would have no effect on the motor direction.



Thanks, Jim - that's just as I suspected. I do, however, want to install a master on/off switch between the wall and the VFD - something I can knock with my knee in an emergency. But I'm glad the VFD will allow for reversing - the modern VFD's really amaze me!
...Doug in Arizona


----------



## JimDawson (Jul 11, 2015)

The master switch is a great idea.  (Technically called a Service Disconnect)

The VFD probably also has an emergency stop function, again consult the user manual.


----------



## mksj (Jul 11, 2015)

Ideally you do not want to power down the VFD as part of an emergency stop, as you can loose the braking function that the VFD can provide. As mentioned, control of the VFD functions usually are performed by the programmed inputs, the manual power switch should be used to disconnect the power when you are not using the machine. In some cases I have seen a contactor used to disconnect power to the VFD in specific E-Stop applications.


----------



## ch2co (Jul 11, 2015)

What VFD are you using?  All of the controls on my unit, start, stop, emergency stop, forward, and reverse work just as they normally do. They just control
low voltage inputs to the VFD that in turn does all of the power switching.  One thing that is very important, NEVER put a switch between 
the VFD and the motor, you will end up having to buy a new VFD if you do. I have a power switch on the 220 single phase input to the VFD as
a way t0 shut the unit off when its not in use.  Speed control on my unit is controlled by a little potentiometer knob on the VFD itself, but
it could be controlled by a remote potentiometer on the lathe itself, again using low voltage wiring  going to the VFD. I was initially taken aback
by the manual but after a few sticky note book marks, I finally figured it out and have never looked back.  

Chuck the grumpy old guy


----------



## cazclocker (Jul 11, 2015)

ch2co said:


> What VFD are you using?  All of the controls on my unit, start, stop, emergency stop, forward, and reverse work just as they normally do. They just control
> low voltage inputs to the VFD that in turn does all of the power switching.  One thing that is very important, NEVER put a switch between
> the VFD and the motor, you will end up having to buy a new VFD if you do. I have a power switch on the 220 single phase input to the VFD as
> a way t0 shut the unit off when its not in use.  Speed control on my unit is controlled by a little potentiometer knob on the VFD itself, but
> ...



My VFD is a TECO JNEV-201-H1.  Here's the current link to the unit where I bought it: http://dealerselectric.com/JNEV-201-H1.asp
I agree the manual is screwy and hard to understand. But I can muddle my way through it.
...Doug in Arizona


----------



## Wheresmywrench? (Jul 28, 2015)

I programmed/wired my Teco VFD to use the external functions so I could use the switches on my lathe control panel. Just wired them to the VFD and I run it that way.


----------



## berniehernandez (Mar 16, 2016)

I agree, you want to use the Stop or E-Stop to stop in an emergency. You can also wire extra Stop or E-stop switches in series and mount then in a convenient location. You and evan mount one as an interlock for the chuck key, lathe won't run till the Chuck Key is put away. Never can be too safe.


----------



## British Steel (Mar 16, 2016)

berniehernandez said:


> I agree, you want to use the Stop or E-Stop to stop in an emergency. You can also wire extra Stop or E-stop switches in series and mount then in a convenient location.



A good place for an E-stop is by the entry door, so your loved ones don't have to dodge your flailing corpse to stop that annoying flapping noise



berniehernandez said:


> You and evan mount one as an interlock for the chuck key, lathe won't run till the Chuck Key is put away. Never can be too safe.



Unless, of course, you have so many chucks and keys there's always a spare to go in the interlock...

For the fastest stop in an emergency, use the VFD stop / E-stop function and add the required brake resistor if it allows for one, the energy from the chuck/spindle/work gets dumped into the resistor and everything stops MUCH faster! If you don't want to pay the manufacturer's (rather inflated) price, there are lots available from Chinese gents on Ebay, I've set mine up with about 90 Ohms, 1500W rating (it's a 400v inverter, 3HP motor, heavy spindle and chucks with lots of momentum), which stops VERY quickly without the usual "OV" over-voltage trip.

If you have a 3rd shaft for electrical forward and reverse switching, it's easy to add a no-volt release contactor in the line to the VFD, fit a "neutral switch" in series with the "on" button so that you can't power up the lathe with it in Fwd/Reverse and surprise yourself with a spinning chuck!

Dave H. (the other one)


----------



## stupoty (Mar 16, 2016)

If you have a threaded chuck don't stop it toooo fast or a new emergency will arise  

I set mine to slow down over a longer peried after that 

Stuart


----------



## sanddan (Mar 16, 2016)

I have a Teco JNEV on my mill and the manual states that you can only install their braking module and not the braking resistor Dave H. described. If anyone knows how to get a simple resistor to work with that VFD I'd love to know how.


----------



## mksj (Mar 16, 2016)

I looked into this a while ago for the JNEV VFD and the braking mosule cost almost as much as the VFD, they no longer had the braking module, the electronics (braking transistor) are not built into the VFD so one can't just add a resistor. Even the replacement version the L510 is missing this unless you are getting the 460V models.  They can still brake fairly decently electronically if using it on a smaller machine.


----------



## berniehernandez (Mar 16, 2016)

British Steel said:


> If you have a 3rd shaft for electrical forward and reverse switching, it's easy to add a no-volt release contactor in the line to the VFD, fit a "neutral switch" in series with the "on" button so that you can't power up the lathe with it in Fwd/Reverse and surprise yourself with a spinning chuck!



Most VFD's will not start if powered up in Run mode, unless you intentionally program it to do so. I never want my lathe to start spinning on power up. maybe a pump I would.


----------



## Steve-626 (Mar 17, 2016)

cazclocker said:


> I'm running 240VAC into my VFD, and then into the motor which is a 3-phase. Where is the most logical place to create a reverse-direction option? Is that one of the options on my VFD, or do I need to install a switch between the 240VAC wall source and the VFD?



Where is the most logical place to create a reverse-direction option? Is that one of the options on my VFD,
Yes
It's built into the VFD features, the manual shows how.

do I need to install a switch between the 240VAC wall source and the VFD?
Yes I install a double pole switch to be able to turn it off and cut the power to both lines when I leave the shop.
But that will not reverse it.


Read the manual

http://s1085.photobucket.com/user/TheCount12345678910/media/FM50page17wiringdiagram-EDITING.gif.html

That is a diagram for a different teco, read the manual and make sure.

https://www.tecowestinghouse.com/Manuals/ev_operating_manual.pdf


----------

