Teco VFD and emco V13 lathe wiring question

My new/used Emco V13 lathe will be here next Monday.

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Also have Teco n3-203-cs VFD coming so I can convert single phase to 3 phase.

http://www.tecowestinghouse.com/PDF/N3_Compact_Drive.pdf

The basic wiring of the main power is simple but my quesition is with regards to the existing switches on the machine and if they need to be rewired into the VFD?
I would prefer the least wiring as possible but want to be able to take advantage of the variable speeds that the VFD will provide.

My guess is that there the following controls on the lathe
1- on/off
2- high speed/low speed - it is a 2 speed motor
3- Forward/reverse, I think but am not sure.

I am wondering if anyone has experience wiring on of these. It looks like there are a lot of programing options. Way more than I feel I will need.

Thanks
Greg

Greg,

Haven't done a Teco and haven't done a Emco so take this with a grain of salt. A drives typical logic program responds to maintained contacts only. Most typical lathes and machine tools use mags that respond to momentary commands. To use a factory momentary command with a frequency drive will require some type of latching circuit. If your Emco has mags that are controlled by factory on-board buttons you can use those mags to control the logic circuit of the frequency drive.

I think you are going to have to chose only one wiring configuration for your two speed motor when you install the drive.

Stuart

I may have to rethink this VFD thing if I can only use one speed for this motor. I do not want to loose the torque that the low range would provide or the speed the high range would provide by having to wire the VFD one way or the other.

I am no electrician so some of the terms are greek to me.

Greg,

Don't take my word for it...I'm a Millwright! Remember that the frequency drive will allow you to put the pedal to the metal and hit probably 400 HZ which certainly is 'high speed'! Don't give up...more X-spurts will be along shortly.

Stuart

"quesition is with regards to the existing switches on the machine and if they need to be rewired into the VFD?"

None. Do not put any switches between the drive and the motor. They are not needed and can possibly
damage the drive if operated while the motor is under load.

Your two speed motor is probably consequent pole and as such is twice the HP rating on high speed as
on low speed. Check the nameplate to be sure this is true. The typical best way for this is to hard-wire
the motor into the high range.

When you reduce the motor speed below nameplate speed it becomes constant torque with this drive.
So you lose no torque this way.

My suggestion is to have fused, switched input for the incoming power to the drive. A small buss fuse in
a holder and a small toggle switch is fine.

Then remote the important drive functions to a small utility box mounted in a convenient place for the
operator. Really you need only a small, center-off, two position toggle switch (fwd/off/rev) and room
for a small variable resistor for speed control.

Avoid for the time being, lights, readouts, extra switches, meters, and so on. You can always add them
later if you really find you need to know the EXACT spindle speed at all times.

The paper manual does not have all the programming information. Use the online or the cd rom that
comes with the drive to figure out the programming details to get the control logic you want, which
is, fwd/off/ref via three wires, and external speed control via the external potentiometer, again three
wires.

Mount the drive in an area free from chips and with air circulation. Many use an enclosure large enough
to allow convection to cool the drive, or put screened vents in the enclosure. I like to set the programming
on the drive to have the fan run at all times when the drive is powered.

If you would like to see photos of representative drive setups, say so.

Jim,
So you are saying I would not use the existing controls on the lathe? I would wire directly from the vfd to a separate box with a start, stop, forward, reverse and resistor for speed control?

Yes, if you have some photos I would like to see your set up.

Could I wire the vfd to the existing control switches? Would the existing wiring have to be removed from the controls if I used the existing switch controls? If I do not use the existing controls and wire up control switches to a remote box should the factory wiring be disconnected?

Sorry for the dumb questions, I am electrically challenged,

Greg

Greg,

The only caveat is the power output of the drive (motor) must be directly wired to the motor of the lathe...this is a real no brainer!

The logic circuits of the drive can be wired to anything you desire as long as they provide the required switch closure. If you have buttons you want to use on your lathe for the sake of looks and convenience, then you can use them...they will eventually terminate at the logic buss of the drive. As I tried to say earlier, most drives only accept maintained closures for their control...most machinery uses momentary switch closures. This means some type of relay to pull this off...very simple.

Your buttons probably are momentary and control some mags in a electrical enclosure somewhere. You merely pull the power wiring off those mags, leave the control wiring and, voila, there are your relays. The control for the drive is then wired to non-powered contacts on the mags and your stock buttons control the mags and the mags turn the drive on and off.

Stuart

Hey Greg, I'm from Fargo! Been away for years ;-)

Mrgt350 said:

Jim,
So you are saying I would not use the existing controls on the lathe? I would wire directly from the vfd to a separate box with a start, stop, forward, reverse and resistor for speed control?

Yes, if you have some photos I would like to see your set up.

Could I wire the vfd to the existing control switches? Would the existing wiring have to be removed from the controls if I used the existing switch controls? If I do not use the existing controls and wire up control switches to a remote box should the factory wiring be disconnected?

Sorry for the dumb questions, I am electrically challenged,

Greg

Click to expand...

Greetings!

In regard to wiring up the VFD, Be BOLD, It's worth the effort.

I have two lathes on VFD's and all the lathe control switches are wired into the VFD control functions.
http://www.practicalmachinist.com/v...athes/wired-up-vfd-weiler-lz330-today-237430/

Mains power on and OFF to the VFD are switched, and then the VFD power out to the motor is Hard wired. As mentioned, Just wire the two speed motor on high speed.

I'm not familiar with your lathe, does it have provision to stop and start, Fwd and Rev the spindle from an apron control? If so, Those switches/relays are an easy connect to the same functions on the VFD. And switching from the Apron is SOOOO nice. Most VFD's have a requirement for only three wires to preform these functions. You would need to disconnect any "across the line" mains connections to the present controls, but that is not hard ;-)

The addition of a speed control is as easy as locating a convenient protected place to fit a 5K potentiometer and run a control wire pair.
I use phone Wire for everything. It's readily available and has several pairs of wires in one casing. I suppose long runs of this wire could see a problem with noise, but I have had no troubles at all.

Get the manual for your VFD, Become familiar with the control functions and connections, Then Build them into your lathe.

You will thank yourself every time you walk up to the machine!

Cheers

Cal
In VT.

Cal,
Thanks for the reply. I would like to retain the original switches and controls. Attached is a picture of the controls, two pictures under the main picture of the lathe.

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There is one picture of the high/low speed switch, on and emerg off. The other picture shows a lever on the right side of the carriage. This lever is a 3 position lever, up is left, middle is off, down is right. That is the extent of the controls I need to wire to the VFD. As you suggest a potentiometer would be nice for quicker speed changes and this can be added along with a tach at a later date.

Bet you wish you were back in Fargo.

Greg

I'm sure every switch, wire and connection you will need is behind that "beauty plate" that covers the gear change box.

I would NOT plan to use the two speed switch, but you could use the hole for your speed pot. The on and Off buttons are there also, Getting a control wire to the VFD is just following the internal wire runs within the lathe.

Good luck!

Cal

You can if you wish use the existing switches in the machine, wired up to the logic inputs of your
drive.

You will need to get into the switches that are there, and find out if they are normally open,
or normally closed, and if they are maintained contact or momentary.

If they are not the correct type however do not dispair as you could replace them with
the same style in a version that is correct for controlling the drive.

Read the manual so you can keep the E-stop buttons active.

jim rozen said:

You can if you wish use the existing switches in the machine, wired up to the logic inputs of your
drive.

You will need to get into the switches that are there, and find out if they are normally open,
or normally closed, and if they are maintained contact or momentary.

If they are not the correct type however do not dispair as you could replace them with
the same style in a version that is correct for controlling the drive.

Read the manual so you can keep the E-stop buttons active.

Click to expand...

Jim,
I am thinking I can do this now. Main power is turned on with a key type switch - either on or off. The start button is what looks like a momentary switch. My guess is that this will need to be a open/closed switch. I just found and downloaded a operators manual that includes a wiring diagram. Will be reading it tonight.

Greg

Does this lathe have a magnetic brake?

Stuart

atomarc said:

Does this lathe have a magnetic brake?

Stuart

Click to expand...

Yes I believe it does.

Greg,

If you intend on using that feature your chore of wiring the drive will be a bit tricky. I looked at a wiring diagram for what appeared to be the same machine and there is indeed a enclosure with a mag and some relays in it. These are things you want to keep and have them interface with the logic on the drive. When I say 'interface' I am saying they will act as switch closures activated by their original factory wiring and buttons.

I would guess the red mushroom E-stop button drops power to the motor and energizes the magnetic brake..this is just a guess. Typically when you do this, the main mag drops out so that when you pull the button back out the lathe does not suddenly start.

When you are turning a part, the apron control would be pulled up to run the lathe forward. If something happened and you smacked the red E-stop, the brake would energize and the lathe would stop. Now you clear the problem and pull the E-stop out but the lever on the apron is still in the FWD position. The lathe should not start...not until you drop the apron lever to STOP then move it again to FWD or REV. This is how it should operate I believe. This is how a lathe with a foot brake operates...at least this is how my lathe with a foot brake operates.

The control 'logic' on your lathe is taken care of with mechanical relays in the electrical enclosure. For the lathe to operate in this safe, stock fashion you have to interface those stock relays on the lathe into the logic you want the drive to see.

These are just things to think about...maybe your lathe is setup completely different. A careful analysis of the components of the enclosure will tell you how it works. The only 'known' is that the magnetic brake is going to need some special wiring which is not going to be found in the frequency drive. Coil voltages of any onboard devices (stock) will have to be proper to achieve what I have described above...that could be a sticky wicket.

Stuart

The brake may release when power is applied. If that's the case then converting the
E-stop button into a normally closed switch in series with the incoming line power will
do two things. The brake will be applied when the button is pushed, and the
motor will not restart (per the VFD instructions for programming - this is the default
setup on those drives) when the E-stop button is cleared.

MSC sells red mushroom buttons like that in 'maintained' configuration, with
NO and NC contacts in one unit.

Thanks for the heads up on the magnetic brake. Nothing is simple is it.

jim rozen said:

The brake may release when power is applied. If that's the case then converting the
E-stop button into a normally closed switch in series with the incoming line power will
do two things. The brake will be applied when the button is pushed, and the
motor will not restart (per the VFD instructions for programming - this is the default
setup on those drives) when the E-stop button is cleared.

MSC sells red mushroom buttons like that in 'maintained' configuration, with
NO and NC contacts in one unit.

Click to expand...

Jim,

What would the brake use for power..the incoming single phase or the generated 3 phase of the drive. I don't know how the brake would respond to a variable HZ output of the drive and if the lathe is truly a 3 phase machine, then the brake would have probably only want to see true 3 phase which the OP doesn't have available.

The only point I'm trying to make is that this isn't a cut and dried deal, especially with the discovery of the onboard magnetic brake. There is a logical sequence of things that can and cannot happen on that lathe for safety's sake and some of the factory relays may have to be figured into the logic wiring to the VFD. On any machine I have ever worked on..if you mash a E-stop, everything comes go a grinding halt. If you then pull it back out, nothing should happen. Anything other than this will cause death and dismemberment!

How well will a magnetic brake play with a programmed decel on the drive? Will the drive see a difference between a STOP and a E-STOP..does it have programming parameters that will allow decel on a normal stop but only disconnect and coast on a E-STOP. I don't have this drive so I don't know...you have several if I recall. Can this drive make that distinction? I may be making a mountain out of a molehill.

Stuart

No, not a mountain out of a mole-hill. The brake is a piece of safety equipment and you don't
go around defeating those. So the game then is to figure out how best to retrofit based on the
circuitry that is present.

WITH A VFD, That Mag brake will just be so much baggage!

VFD's have Decel.

Just disconnect the brake mechanism, and use the switch to signal a VFD stop. Same as the apron control.

If the "Power goes out", things shut off "auto-magically"

atomarc said:

Jim,

What would the brake use for power..the incoming single phase or the generated 3 phase of the drive. I don't know how the brake would respond to a variable HZ output of the drive and if the lathe is truly a 3 phase machine, then the brake would have probably only want to see true 3 phase which the OP doesn't have available.

The only point I'm trying to make is that this isn't a cut and dried deal, especially with the discovery of the onboard magnetic brake. There is a logical sequence of things that can and cannot happen on that lathe for safety's sake and some of the factory relays may have to be figured into the logic wiring to the VFD. On any machine I have ever worked on..if you mash a E-stop, everything comes go a grinding halt. If you then pull it back out, nothing should happen. Anything other than this will cause death and dismemberment!

How well will a magnetic brake play with a programmed decel on the drive? Will the drive see a difference between a STOP and a E-STOP..does it have programming parameters that will allow decel on a normal stop but only disconnect and coast on a E-STOP. I don't have this drive so I don't know...you have several if I recall. Can this drive make that distinction? I may be making a mountain out of a molehill.

Stuart

Click to expand...