# PM-1440GT Basic Wiring Changes for using the Contactors to switch the VFD inputs



## mksj (Dec 27, 2017)

I previously outlined the use of new contactors to use to switch the VFD inputs when doing a basic 3 phase VFD lathe conversion, this retains the same functions (and interlocks) as the stock lathe and should operate the same. The VFD adds speed control, and acceleration deceleration control. In order for the manual foot brake to work correctly, one should replace the single pole brake limit switch with a dual pole limit switch with one NC and one NO contact blocks. The NC is used for the stock 24VAC wiring connection, the NO is used to activate a VFD input and issue a free run command (no VFD braking). Be forewarned, there seems to be multiple control system/wiring used on the various 1440GT's I have seen, so this is a concept idea and should only be attempted if you understand and can following the wiring for your 1440GT. Otherwise, I would recommend going with an RPC. Before making any modifications I would contact the lathe manufacturer as to how it will effect your warranty, in most cases it voids anything electrical when any mods are done. Use this information at your own risk.

I have done a number of full control systems for the PM 1236, 1340GT and the 1440GT, as well as other machines. The PM1440GT was a more complicated  full replacement system, and although I did a full control system build recently, it is not something I want to do again. In the most recent system, the VFD is mounted in the headstock cabinet behind the control cabinet. It makes for a very clean simple install and one saves in not having to do a separate VFD enclosure. I am providing a WJ200 parameter file as a starting point and some older schematic designs, the new system is more complicated. The tachometer and sender I wired to the main control board, the speed pot is in the tachometer enclosure. The stock switches and cabling are replaced, but the same 4 switch holes are used in the front panel, a 1/4 hole is used for setting 1 or 2 stage braking. The design below re-configures the stock brake switch to normally open, when the manual brake is engaged it triggers a braking relay which disconnects the power relay latch/VFD signals and sends a separate free run command to the VFD. The spindle lever must be reset to the stop position for the system to be reset.










One install where the VFD was mounted horizontally, but I recommend vertically on L brackets or a 90 degree back panel attached to the bulkhead wall. You can add a power disconnect to the front or side of the headstock base. The braking resistor is also mounted in this space.


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## Firestopper (Dec 27, 2017)

Man, I for one can appreciate the amount of work required to build something like this. Theres a ton of work in design phase let alone researching the parts before you event start to build the system. Then finally you get to machine some parts. Superlative work Mark without question.

Happy New Year!
Paco


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## Alan H. (Dec 28, 2017)

firestopper said:


> Man, I for one can appreciate the amount of work required to build something like this. Theres a ton of work in design phase let alone researching the parts before you event start to build the system. Then finally you get to machine some parts. Superlative work Mark without question.
> 
> Happy New Year!
> Paco


Amen!


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## Ramblerman68 (Jan 6, 2018)

I'm no expert and a true electrical dummy, so if I say Marks stuff works and works well with no reason to even call him for help, I believe that is a true testament  to how well designed, built and delivered  his stuff is.  Super quality stuff, working after almost a year with zero issues on my PM1340GT (also a very nice piece of equipment, btw). Thanks Mark!


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## jbolt (Jan 7, 2018)

Nice work as usual Mark!

With the VFD in the base I would add a shield over the top. Swarf has a way of getting everywhere. My original plan was to put the VFD in the base cabinet on an L plate attached to a full extension drawer slide for easier access. I eventually opted for an enclosure mounted to the base cabinet because it fit my setup more to my liking plus it is less crowded.


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## jer (Jan 9, 2018)

Without Mark and Jay basically holding my hand for several weeks on and off I would not have even attempted the PM1440GT conversion. It works great but not without re-doing most of the wiring in the lathe. If you have a basic, or above, understanding and their help it is possible.


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## mksj (Jan 9, 2018)

Jay and Jbolt, thank you for your comments. Having got my hands on a 1440GT control board, that part of the recommended wiring changes for the basic conversion is a bit more straight forward. You still have the issues as there seems to be different variations of the wiring, color coding and control boards. I agree with Jbolt, that if you have the option for a separate VFD enclosure that is probably preferably, but I have seen several conversions with the VFD in the cabinet which is an alternative. As Jbolt outlined you may want to put a cover plate on the top area above the VFD.  I have not seen a 1440GT in person, so do not know the configuration of the cabinet.

If I were to do any future 1440GT complete system builds, I would opt to have a separate VFD enclosure, but still would mount the control board at the machine in the current control box. This simplifies the process and allows for a smaller VFD box, the control system schematic I currently use retains the stock mechanical brake switch, but rewires it for normally open. When closed it triggers a braking relay which deactivates the other controls and signals the VFD into a free run command. This is more economical than replacing the brake  limit switch.  The spindle lever must be returned to the stop position to reset the system. The basic conversion outlined retains all the lathes stock functions along with speed control and electronic braking. Using a proximity sensor type of stop system, requires a completely different approach/system.

Mark


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## Lucky Liverider (Apr 29, 2019)

mksj said:


> I previously outlined the use of new contactors to use to switch the VFD inputs when doing a basic 3 phase VFD lathe conversion, this retains the same functions (and interlocks) as the stock lathe and should operate the same. The VFD adds speed control, and acceleration deceleration control. In order for the manual foot brake to work correctly, one should replace the single pole brake limit switch with a dual pole limit switch with one NC and one NO contact blocks. The NC is used for the stock 24VAC wiring connection, the NO is used to activate a VFD input and issue a free run command (no VFD braking). Be forewarned, there seems to be multiple control system/wiring used on the various 1440GT's I have seen, so this is a concept idea and should only be attempted if you understand and can following the wiring for your 1440GT. Otherwise, I would recommend going with an RPC. Before making any modifications I would contact the lathe manufacturer as to how it will effect your warranty, in most cases it voids anything electrical when any mods are done. Use this information at your own risk.
> 
> I have done a number of full control systems for the PM 1236, 1340GT and the 1440GT, as well as other machines. The PM1440GT was a more complicated  full replacement system, and although I did a full control system build recently, it is not something I want to do again. In the most recent system, the VFD is mounted in the headstock cabinet behind the control cabinet. It makes for a very clean simple install and one saves in not having to do a separate VFD enclosure. I am providing a WJ200 parameter file as a starting point and some older schematic designs, the new system is more complicated. The tachometer and sender I wired to the main control board, the speed pot is in the tachometer enclosure. The stock switches and cabling are replaced, but the same 4 switch holes are used in the front panel, a 1/4 hole is used for setting 1 or 2 stage braking. The design below re-configures the stock brake switch to normally open, when the manual brake is engaged it triggers a braking relay which disconnects the power relay latch/VFD signals and sends a separate free run command to the VFD. The spindle lever must be reset to the stop position for the system to be reset.
> 
> ...





mksj said:


> I previously outlined the use of new contactors to use to switch the VFD inputs when doing a basic 3 phase VFD lathe conversion, this retains the same functions (and interlocks) as the stock lathe and should operate the same. The VFD adds speed control, and acceleration deceleration control. In order for the manual foot brake to work correctly, one should replace the single pole brake limit switch with a dual pole limit switch with one NC and one NO contact blocks. The NC is used for the stock 24VAC wiring connection, the NO is used to activate a VFD input and issue a free run command (no VFD braking). Be forewarned, there seems to be multiple control system/wiring used on the various 1440GT's I have seen, so this is a concept idea and should only be attempted if you understand and can following the wiring for your 1440GT. Otherwise, I would recommend going with an RPC. Before making any modifications I would contact the lathe manufacturer as to how it will effect your warranty, in most cases it voids anything electrical when any mods are done. Use this information at your own risk.
> 
> I have done a number of full control systems for the PM 1236, 1340GT and the 1440GT, as well as other machines. The PM1440GT was a more complicated  full replacement system, and although I did a full control system build recently, it is not something I want to do again. In the most recent system, the VFD is mounted in the headstock cabinet behind the control cabinet. It makes for a very clean simple install and one saves in not having to do a separate VFD enclosure. I am providing a WJ200 parameter file as a starting point and some older schematic designs, the new system is more complicated. The tachometer and sender I wired to the main control board, the speed pot is in the tachometer enclosure. The stock switches and cabling are replaced, but the same 4 switch holes are used in the front panel, a 1/4 hole is used for setting 1 or 2 stage braking. The design below re-configures the stock brake switch to normally open, when the manual brake is engaged it triggers a braking relay which disconnects the power relay latch/VFD signals and sends a separate free run command to the VFD. The spindle lever must be reset to the stop position for the system to be reset.
> 
> ...


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## Lucky Liverider (Apr 29, 2019)

mksj said:


> I previously outlined the use of new contactors to use to switch the VFD inputs when doing a basic 3 phase VFD lathe conversion, this retains the same functions (and interlocks) as the stock lathe and should operate the same. The VFD adds speed control, and acceleration deceleration control. In order for the manual foot brake to work correctly, one should replace the single pole brake limit switch with a dual pole limit switch with one NC and one NO contact blocks. The NC is used for the stock 24VAC wiring connection, the NO is used to activate a VFD input and issue a free run command (no VFD braking). Be forewarned, there seems to be multiple control system/wiring used on the various 1440GT's I have seen, so this is a concept idea and should only be attempted if you understand and can following the wiring for your 1440GT. Otherwise, I would recommend going with an RPC. Before making any modifications I would contact the lathe manufacturer as to how it will effect your warranty, in most cases it voids anything electrical when any mods are done. Use this information at your own risk.
> 
> I have done a number of full control systems for the PM 1236, 1340GT and the 1440GT, as well as other machines. The PM1440GT was a more complicated  full replacement system, and although I did a full control system build recently, it is not something I want to do again. In the most recent system, the VFD is mounted in the headstock cabinet behind the control cabinet. It makes for a very clean simple install and one saves in not having to do a separate VFD enclosure. I am providing a WJ200 parameter file as a starting point and some older schematic designs, the new system is more complicated. The tachometer and sender I wired to the main control board, the speed pot is in the tachometer enclosure. The stock switches and cabling are replaced, but the same 4 switch holes are used in the front panel, a 1/4 hole is used for setting 1 or 2 stage braking. The design below re-configures the stock brake switch to normally open, when the manual brake is engaged it triggers a braking relay which disconnects the power relay latch/VFD signals and sends a separate free run command to the VFD. The spindle lever must be reset to the stop position for the system to be reset.
> 
> ...


mark,

I noticed on your basic diagram part list you noted the need for a mini toggle switch for jog direction, i don't see that in your wire diagram but I assume that is to change motor direction prior to jog function? Also, I noted that you specified the need for diodes for the uses of a joy stick toggle; I plan on using Automation Direct part#GCX1330-22 for my toggle. I would imaging it too would require the use of diodes. Lastly, the toggle shown on your schematic for the 1 and 2 stage breaking; does this control a parameter in the VFD?

Thanks


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## BigBlue&Goldie (Sep 4, 2020)

I thought I'd bump an old thread instead of starting another......

When doing a basic install, does the Jog function still work as usual without adding the joystick feature outlined in the document?


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## Lucky Liverider (Sep 4, 2020)

Sure does


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## BigBlue&Goldie (Sep 4, 2020)

Thanks Lucky Liverider!

It sounds like the basic installation is the way to go for me. I think the only thing I'm going to add is the potentiometer to take advantage of the VFD. Now, it's just a matter of figuring out if the 1440GT is the way to go.......decisions.


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## izz4u2mm2020 (Sep 13, 2020)

That wiring setup lookd complicated and on the lathe I am trying to fix looks the same. Haing trouble finding replacement contactors. Is it possible to use a VFD and no contactors ??
Thanks for sharing
Manny


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## mksj (Sep 13, 2020)

Might not follow the question, is the issue that you have used contactors? If so they can replaced with any contactor that has the same switching configurations and the same coil voltage of 24VAC.  You can replace them with a mini contactor if you are NOT going to use them for motor current. If you need the Teco replacement contactors they are available through Eisen and are about $50 each. Is this for a 1440GT that has been used or another lahte? This setup is not for new complete builds, but to use the stock control system and contactors to switch the VFD low level inputs.

Stock Teco CU-11 24V 3A1a is Normally Open, 3A1b is Normally closed





WEG Electric CWC series IEC miniature contactor, 7A, (3) N.O. power poles, 24 VAC (60Hz) coil voltage. (1) N.O. auxiliary contact included.


			https://www.automationdirect.com/adc/shopping/catalog/motor_controls/iec_contactors_-z-_starters_-z-_overloads/weg_electric_miniature_contactors_(3-pole)/7_amp_(ac3)/cwc07-10-30v04
		


 WEG Electric CWC series IEC miniature contactor, 7A, (3) N.O. power poles, 24 VAC (60Hz) coil voltage. (1) N.C. 


			https://www.automationdirect.com/adc/shopping/catalog/motor_controls/iec_contactors_-z-_starters_-z-_overloads/weg_electric_miniature_contactors_(3-pole)/7_amp_(ac3)/cwc07-01-30v04
		


I have posted other simple single relay 24VDC 4 pole designs that work with the WJ200 VFD. The design can be modified to use an external 24VDC power supply. In general not using a latching type relay to prevent restart with typical 2 wire control in various scenarios is very dangerous on machinery. On a mill one can use 3 wire control with momentary switches which can be used w/o a power latching relay. The configuration and programming parameters vary by VFD manufacturer.


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## mksj (Sep 13, 2020)

A number of individuals have mounted the VFD in the headstock cabinet off of an L bracket with a mounting plate for the VFD. They have also added a main power disconnect switch in the cabinet.  A braking resistor is mounted in the same cabinet.  This can save a bit of the cost and space vs. adding a separate VFD cabinet, these were full builds where the VFD is mounted in the headstock cabinet. I have attached some updated basic install information for the 1440GT. You must comply with all electrical codes and manufactures recommendations, use this information at your own risk.









Full system replacement boards.


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## AlanB (Nov 12, 2020)

Nice setup. Thanks for sharing and supporting this work.


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