# Pm 1340 Gt Vfd Question



## spring5497 (Mar 3, 2015)

Let me start off by saying I am enjying this site as someone whos is just starting off with my own machines I am learning alot.  I took a machine shop class in college and was a natural according to my instructor, but it's been 25 years since college and I am now in a position to set up my own shop.  I am currently in Law Enforcement and looking at retirement in about 8 years.  I have a co-worker that is willing to work with me to bring me back up to speed and I want to purchase my own lathe and mill to start doing some gunsmithing as well as be able to  suplement my retirment income when the time comes.  I want to make one purchae now for machines that will last and I won't out grow.

I have read every thread on this site as well as every other google search I can find on the subject, so please forgive my lack of knowledge.  I am trying to decide on a lathe and mill purchase and have it narrowed to a PM 1340 GT or PM 1440 B with a PM 932M w/ ES-8 Dro.  Now to where I am having the dilema, it all comes down to one thing, lowest sped on the lathes.  The 1340 is 90rpm vs. 40 rpm on the 1440.  I know as I have read that going with a 3 phase motor and VFD will lower the 1340 down to the speeds I am looking for, but this is where the problems come into play.  First, I don't feel confortable changing the wiring on the 1340, maybe since I haven't don't have the machine in front of me but when I read the theads I am confused and really afraid that I would make a mistake and damage the machine.  Secondly as I read the threads I see the added expense of electrical components pushing my already tight budget over the limit.

So after all of that here is the major question:  What is the cost to add the VFD to the 1340 and hoe hard is this to install.  Please understand that I am not uneducated but I am ignorant when it comes to electricity!  I don't want to damage a machine costing that much.

My next question to anyone that can answer is:  Other than the obvious size differences is the differnce of being manufactured in China vs. Taiwan a real reason to choose the 1340 over the 1440?
If I go with the 1440 B and the 932M w/ ES-8 DRO I am under my $9000 budget buy about $500 but if I go with the 1340 GT and 932M w/ ES-8 DRO I am over my budget by about $400, plus the cost of adding the VFD.

Any and all help is greatly appreciated.


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## Karl_T (Mar 3, 2015)

I just went to automation direct a 1 hp is $250, 2hp is $300, 3 hp is $350. don't know motor size on your lathe
http://www.automationdirect.com/adc...+/+GS2+/+DURApulse+AC+Drives"&start=0&rows=10

I say work some OT, or hock your wife's wedding ring  , and buy the better machine.

Installing a VFD is no big deal if you let us help you.


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## mksj (Mar 3, 2015)

If you buy the 3 phase PM1340GT, you only have the expense of the VFD and a few electrical components to convert it, so maybe $250 in total.  Although the the Hitachi WJ200 is what QMT usually bundles with the machine,  something like the TECO JNEV-202-H1 will work just fine and they run about $180. http://dealerselectric.com/JNEV-202-H1.asp

The PM1340GT motor space is very compact, so replacing the stock 1 phase motor with a 3 phase, you have very few options and will at least double the cost. The conversion to VFD is not necessarily difficult, there are different options of how to implement it. Some people keep the stock 240VAC to 24VAC transformer to power the light, but remove the contactors, relay and board wiring. You retain the wiring to the direction controls. You install a single 4 pole relay on the main board and wire everything up. See attached file with a suggested schematic and approximate parts costs. I would not use input 4 for 2 stage breaking, but others have requested it. The VFD control connections are all low voltage, it does require some reconfiguration of the front panel switches which is easily accessed.

The motor is directly connected to the VFD, the VFD is connected to your main power and should incorporated a power disconnect switch/breaker which is usually through an enclosure or electrical sub panel. I use a 20A plug for my machine which comes off a dedicated breaker in my garage sub panel. So there is not really anything to break relative to the lathe. There are no other electronics on the lathe to damage. That being said, the motor/VFD/line power is high voltage (240V), so a basic understanding of proper wiring is required. You can also have an electrician review, and/or do the main power hook-up.

On the mill DRO, the ES-12 provides a few more graphical options for machining, but it comes down to cost.

Different info on the PM1340GT at this site and individual comments, so a very nice machine. I have had issues with the supplied chucks in the package having poor TIR and balance issues, you get what you pay for.


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## mksj (Mar 3, 2015)

Need to clarify 2 things on the above recommendation (Do not understand why you can not edit these posts).  I reviewed the TECO JNEV series and Dura Pulsed VFD manuals and the 24V voltage that is used for the digital inputs signals has a maximum current of 20mA and is not sufficient to drive the relay and LED light in the schematic provided.  The Hitachi WJ200 is 100mA, and is sufficient. As mentioned, there are different wiring options, a power relay to the controls is usually used so if the power drops out or the E-Stop is hit, the machine will not restart in the run mode when reset.

The flexible non-conduit wire to connect the VFD to the motor is 3 power wires (usually three black labeled 1, 2, 3) plus a green or green/yellow ground, and has a separate shield which connected at the VFD end. The green/yellow ground wire must be connected at both ends, VFD and motor. Usually can find this cable on eBay, (search Traycontrol OR Helukabel).


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## spring5497 (Mar 3, 2015)

Thanks for the information, I am seriously considering this option now.

If I go this option I plan to buy the 3 Phase model.  Is the space also tight in this model or just the single phase?

Do you think this option is worth the approx. $1000 investment over the 1440B?


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## mksj (Mar 3, 2015)

Motors are the same size, it is just a tight space and their 2HP motors just fits.  A replacement motors with blowers tend to be too long, so you need something like a TENV type and check the dimensions. Until you have the machine in front of you, it is hard to get a handle on it. Same goes for the wiring.





The work scope of the two machines is similar, but I believe the quality of the PM1340GT is worth it when you look at the total investment over the years. That being said, the 1440B is also a lot of machine, comes with all the accessories, and has a 2" spindle bore, but I would suggest the 1440BV version with the VFD for the nominal price difference. Only 2 gear speed ranges, ability to dial in a specific speed for the job, 3 phase motors give a smoother finish on the work piece. The VFD give better motor control and can provide flat torque over a wide operating speed.


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## GA Gyro (Mar 26, 2015)

spring5497 said:


> Thanks for the information, I am seriously considering this option now.
> 
> If I go this option I plan to buy the 3 Phase model.  Is the space also tight in this model or just the single phase?
> 
> Do you think this option is worth the approx. $1000 investment over the 1440B?



The 1340GT VS (variable speed) is NOT a 3 PH motor with VFD from the factory... rather the same lathe without the full spindle drive gearbox... rather a fully variable speed DC motor.  It is a different animal than the 1 PH or 3PH models.  

Personally.... wiring the VFD is not that big a deal... just ask for the help you need here... until you understand.  

If it were me.... I would get a 1340GT with 3PH motor, let Matt send you a Hitachi WJ200 VFD, do the wiring, and enjoy the lathe.
The build quality on the 1340GT is very high for this class of machine!


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## jds (Mar 26, 2015)

Spring,
I am in the same boat as you,  I can pull the plug in about 30 months from my LE job.  Went to a local votech recently, I have been on the fence about purchasing machines.  Bought a used bridgeport that became a project and I was saving up for a Prototrak bed mill and a Haas TL2.  I have this bug to shape metal and those bigger machines were a ways off and I am not getting any younger.  I had researched machines for a while and even looked at a lathe made in Canada.  After following Zmotorsport's purchase and review of the 1340GT, I decided to buy one and picked up a 935 T-S also.  I have had no problems with Matt at quality machine tools and should be receiving the machines in a week or two.  I ordered mine end of November 2014.  I will be running them both off of VFDs.  The folks on this sight are pretty friendly and usually go out of their way to help others.
JD


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## coolidge (Mar 26, 2015)

Did someone say Haas TL2?


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## GA Gyro (Mar 26, 2015)

And I might add there are a LOT of folks who have purchased this combination:  PM1340GT and PM935TS/TV mill.  
Each has added their custom ideas to a stand, wiring, accessories, etc... and all of them I have exchanged with, were more than willing to offer help.

One could easily be in worse shape for advise...


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## GA Gyro (Mar 26, 2015)

coolidge said:


> Did someone say Haas TL2?
> 
> /QUOTE]
> 
> Yeah, I may resemble that post (the drooling)... However getting that beast into my shop may be a real project.


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## tmarks11 (Mar 27, 2015)

mksj said:


> I reviewed the TECO JNEV series and Dura Pulsed VFD manuals and the 24V voltage that is used for the digital inputs signals has a maximum current of 20mA and is not sufficient to drive the relay and LED light in the schematic provided.


Good catch.  You could always use a $8 ice cube relay from the digital output of the VFD to drive the contractor.

I have a Generac load unloader for my genset, and that is what it does.  Control signal drives 24V ice cube relay, relay drives contractor.


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## NoSquib (Apr 10, 2015)

Sorry for jumping in late here, and not trying to hijack.  Smack accordingly if I'm out of line but, I too am very seriously looking at a variable speed PM.  I THOUGHT I had my mind made up on a "Green" machine, but while lurking another site (one not so friendly to overseas machines) someone posted a link to the 1440 BV.  So, for the 9,968th time, I'm back to square 1 in my decision making process.  
I could go on about my power situation, needs, etc. but I'm still not sure if I'm being rude by jumping in at this point....


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## JPH (May 2, 2015)

I am in a similar spot, NoSqib !   What decided for me was a post on a parallel thread here in which Matt himself posted comments.  Then today when I called to check on availability of a lathe and a mill I ended up talking to Matt directly.  I basically chucked my green catalog.  But the problem for me now is should I really go for the 1340GT ?  You know, I started looking at the 602, crossed over to the 1127, now I am looking at the 1340.  Slightly crazy.  But then, I probably will not get another lathe rest of my life.

I don't know if I understood GA Gyro correctly, but if I did, it sounds like getting the 1340GT with a 3 phase motor, (and the gear box); then adding a VFD is the way to end up with the best results.  I wonder, is the 2 HP motor 3 phase? ... It's listed as an option: 220V, 3 phase, 2 HP:  

http://www.machinetoolonline.com/files/PM-1340GT_Quote_All_Customers.pdf

Now I am going to watch (for the n-th time) the 30 minute review of the 1340GT with a new mind set.






Thanks for all your comments.


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## mksj (May 3, 2015)

Available in 1ph and 3ph with a 2hp 220v motor. Same price. If you get the 3ph motor, you can add the VFD and use the stock motor. Adding A VFD is not a drop in project. Most people gut the control box, some mount the VFD in the cabinet, others on the wall. There is a lot of information in this forum of how to do it, examples, and support. I think we all start with buying something smaller and less expensive, put you evolve to the buy it once philosophy. It does stretch the budget by quite a bit.


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## GA Gyro (May 3, 2015)

JPH said:


> I am in a similar spot, NoSqib !   What decided for me was a post on a parallel thread here in which Matt himself posted comments.  Then today when I called to check on availability of a lathe and a mill I ended up talking to Matt directly.  I basically chucked my green catalog.  But the problem for me now is should I really go for the 1340GT ?  You know, I started looking at the 602, crossed over to the 1127, now I am looking at the 1340.  Slightly crazy.  But then, I probably will not get another lathe rest of my life.
> 
> *I don't know if I understood GA Gyro correctly, but if I did, it sounds like getting the 1340GT with a 3 phase motor, (and the gear box); then adding a VFD is the way to end up with the best results.  I wonder, is the 2 HP motor 3 phase? ... It's listed as an option: 220V, 3 phase, 2 HP:  *
> 
> ...



Yes, that is what I was trying to say... IMO the 1340GT with 3PH motor and VFD is the better choice... my opinion... and it appears the opinion of many here.

As to the VFD... while it does require wiring, it is not rocket science.  There are a number of folks here who know nothing about wiring, which have carefully followed others, and done it.  If one feels they do not want to attack electricity alone, a friend who does would be a good investment for a rainy weekend.

I am also one that went back and forth for months on which machines to buy... ended up with the PM935TS and PM1340GT, both with 3PH motors and VFD's.  My thinking is similar to yours... I did not want to find I needed more machine and upgrade, rather purchase a little too much machine up front, and grow into it.  In the future, I may have a need for a CNC mill... at this time that appears to be the only machine upgrade I see in my future.


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## JPH (May 3, 2015)

Thanks.  I am making a spread sheet my "cart".   I probably will have left out stuff I need which I can get from Matt.  Maybe I should post it for comments.


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## JPH (May 3, 2015)

GA Gyro said:


> Yes, that is what I was trying to say... IMO the 1340GT with 3PH motor and VFD is the better choice... my opinion... and it appears the opinion of many here.
> 
> As to the VFD... while it does require wiring, it is not rocket science.  There are a number of folks here who know nothing about wiring, which have carefully followed others, and done it.  If one feels they do not want to attack electricity alone, a friend who does would be a good investment for a rainy weekend.
> 
> I am also one that went back and forth for months on which machines to buy... ended up with the PM935TS and PM1340GT, both with 3PH motors and VFD's.  My thinking is similar to yours... I did not want to find I needed more machine and upgrade, rather purchase a little too much machine up front, and grow into it.  In the future, I may have a need for a CNC mill... at this time that appears to be the only machine upgrade I see in my future.



When you say 3PH, do you mean 3 phase?   For the 940 Matt's site doesn't list the 3 phase as an option:   I'll make a note to ask for it.


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## GA Gyro (May 3, 2015)

JPH said:


> When you say 3PH, do you mean 3 phase?   For the 940 Matt's site doesn't list the 3 phase as an option:   I'll make a note to ask for it.



Yes, when I say 3PH... I mean 3 phase...
As opposed to 3HP... which is 3 horsepower.  

My mill is both 3PH and 3HP... gets confusing.

I am sure the 940 will be available with a 3PH motor... unless Matt plans to offer them with brushless DC motors.  This version, if it is similar to the 932VS, has a different gearbox and a truly variable speed DC motor... and it costs more.  It is suitable for CNC applications though.  
Honestly, I do not know how the 940 will come.  I do know that Matt designs the features himself, and the factories build them to his specs.  
Subtle things like better bearings, NO plastic gears (some grizzly's have plastic gears), beefier parts, etc... 
Comparing Matt's machines to others is truly an apples to oranges arrangement (definitely not apples to apples).


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## NoSquib (May 4, 2015)

JPH said:


> I am in a similar spot, NoSqib !   What decided for me was a post on a parallel thread here in which Matt himself posted comments.  Then today when I called to check on availability of a lathe and a mill I ended up talking to Matt directly.  I basically chucked my green catalog.  But the problem for me now is should I really go for the 1340GT ?  You know, I started looking at the 602, crossed over to the 1127, now I am looking at the 1340.  Slightly crazy.  But then, I probably will not get another lathe rest of my life.
> 
> I don't know if I understood GA Gyro correctly, but if I did, it sounds like getting the 1340GT with a 3 phase motor, (and the gear box); then adding a VFD is the way to end up with the best results.  I wonder, is the 2 HP motor 3 phase? ... It's listed as an option: 220V, 3 phase, 2 HP:
> 
> ...




Ha, 
  I know exactly how you feel.  I will tell you that I am one who researches things into the ground.  Most of the time I end up beating my head into the wall I research it so much (good thing I'm not ready to purchase just yet).  
  One thing that really had me scratching my head was wiring.  I consider myself to be above average in the mechanically inclined area, but electrical, nope.  That being said, I was "gun shy" about a 3 phase machine, vfd, etc.  But I have watched literally hundreds of videos on it, and I think anyone with a little inclination could pull it off.  Actually, I've almost decided to complicate it more by using a VFD with a detachable face.  Check out the GS2.  Not crazy expensive, very straight forward, and almost limitless options.  I especially like that for little money, you can add a breaking resistor.  Take a few min and look at this.  






ugh, apparently my ignorance of forum's has shown again.  I can't figure out how to make the video show up like your, it just looks like a link.  sorry.


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## NoSquib (May 4, 2015)

GA Gyro said:


> Yes, when I say 3PH... I mean 3 phase...
> As opposed to 3HP... which is 3 horsepower.
> 
> My mill is both 3PH and 3HP... gets confusing.
> ...



GA,
  it is my understanding that using a VFD with potentiometer, you can vary the speed much more infinitely, not only with gears, but also by adjust the frequency of electricity to the motor, correct?


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## GA Gyro (May 4, 2015)

NoSquib said:


> GA,
> it is my understanding that using a VFD with potentiometer, you can vary the speed much more infinitely, not only with gears, but also by adjust the frequency of electricity to the motor, correct?



Yes, that is correct.

Using a VFD with a 3PH motor accomplishes 2 things:
1) It allows you to run a 3PH motor from your single phase home electricity feed, and
2) It allows you to vary the Htz (cycles/second) electrical feed to the machine, to vary the speed of the motor.  

Some notes on this: 
The reason for a 3PH motor, as you probably have read, is to smooth out rotational torque.  A single phase motor tends to have variations in rotational torque (jerking if you please, which are not noticeable most of the time)... this is due to the phase start-stop-start.  With 3PH current, the phases overlap... so smooth rotational torque.  When is this an issue... when running the lathe or mill at very low speeds... like threading.  The difference between a rough finish and a smooth finish on larger threads... can be partly due to a single phase motor.  Others have explained this in more detail.
The other note is on how slow and fast you can run the motor.  While the VFD will take the motor down to a very low RPM, as well as wind it up to almost flying... the motor itself, if not rated for this behavior, will be damaged.  A good rule of thumb is to keep the VFD feed between 45Htz to 75 Htz... given that 60 Htz is normal.  Again, there are more thorough explanations in other posts at this forum.  
For more thorough explanations... search through the PM threads for any thread that includes a VFD or setting up a new machine.  Last time I did that search, I spent the entire evening reading... and I did not go back father than about a year and a half... 

Sorry for the short explanations, need to run.

Best to you!

GA


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## JPH (May 4, 2015)

It showed up as a video.  I have to go do some yard work now, but in the evening, I will definitely look at that.  Thank you.

Say, NoSquib, (does that mean you are 6+ feet and 200+ lbs ? or no squib in the sense shooters use the term, meaning bang every time?)  have you ordered your lathe / mill yet ?

I am ready to do so (as soon as I get the spring chores done ... we are at 6500 feet and spring is just arriving here), and any specifics about what to order would be appreciated.

I have a project for the machines, of cource, but I ran across two new interesting tools that I can make with the machines.  If you have any interest let me know.  One is CO2 cooling, where we take advantage of sublimation of CO2 to deliver it as a gas, but take advantage of self re-solidification to deliver high density of CO2 as dry ice to the point of the heat source (none of this is my idea, by the way);  And the second one is to make a RHVT, a cold/hot air gun from compressed air.  Commercial guns are available, but it was invented in the 30's, patented in that time frame, and there is lots of research results published in other countries, even specific pressure and sizes of the parts to yield optimum cold air from a vortex which can then be separate cold from hot air.  I am now at the stage of finding everything I can of what others have done.  I would be glad to send you or post the recent interesting articles.  

Anyone is welcome to join, since I am headed toward open-source (the source ideas are not mine to begin with ! ).


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## JPH (May 4, 2015)

NoSquib said:


> GA,
> it is my understanding that using a VFD with potentiometer, you can vary the speed much more infinitely, not only with gears, but also by adjust the frequency of electricity to the motor, correct?



The fan for the motor itself is critical for slow RPM.  A separate fan at constant high speed would be best, instead of a fan that is tied to the shaft of the motor.

The potentiometer sends a voltage signal to the electronics that puts out a corresponding frequency to the motor.

I am thinking of ordering the 1340GT with a 3 phase motor, but WITH the regular gear box.  That way, I think there are many more operational options, as in put it in low mechanical (geared) speed, and then further slow the motor from the nominal 1700 rpm to something slower.


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## NoSquib (May 4, 2015)

JPH,
  I have not yet ordered mine.  I'm still in the study/research phase...  Since stumbling across the PM line, it appears that it's quality is unparalleled for an import. I also am almost certainly going with the 1340, but have yet to rule out the 1440.   I like that is has a large diameter spindle through hole and relatively short spindle width.  Turning longer material set up either with an outboard or chucked spider will be much more accurate and secure.  With the GS2 VFD, you (can if you so choose) have the VFD mounted in such a way that it will not be subject to everyday beat and bang, dust, etc, but you can have the control head conveniently located, with your cyclic rate visible as well as adjustable.  With that easy at your fingertips, you can simply go to a 60Hz rate (ordinary rating for most 3 phase) and use the gears just like you would w/o the VFD.  I've done countless hours of research and to date, that is the most bang (no pun intended) for your buck.  I also am seriously contemplating the use of the braking resistor for safety reasons.  Back in the day when running a line making precision production parts for an auto manufacturer, I have seen what can happen when things go sideways...  Sometimes, you need things to stop like RIGHT NOW.  Lol  
  I like the idea of a fan set up for maximum cooling when turning at lower speeds.  In my research, I have learned that some (if not the majority) have experienced some higher motor temperatures when making deep cuts at lower cycle speeds, this may help with that?
I'm certainly not an electrician, I'm simply researching machines and setups that will best fit my needs in the future.  I hope folks don't think I'm trying to hijack the OP, it is not my intention, I'm just trying to bring what I have found to the table in hopes of either confirmation or critique, who knows, maybe it will help someone else!?

PS.  I'm not  6+ feet and 200.  LOL  Good eye, good sir!


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## JPH (May 4, 2015)

NoSquib said:


> JPH,
> I have not yet ordered mine.  I'm still in the study/research phase...  Since stumbling across the PM line, it appears that it's quality is unparalleled for an import. I also am almost certainly going with the 1340, but have yet to rule out the 1440.   I like that is has a large diameter spindle through hole and relatively short spindle width.  Turning longer material set up either with an outboard or chucked spider will be much more accurate and secure.  With the GS2 VFD, you (can if you so choose) have the VFD mounted in such a way that it will not be subject to everyday beat and bang, dust, etc, but you can have the control head conveniently located, with your cyclic rate visible as well as adjustable.  With that easy at your fingertips, you can simply go to a 60Hz rate (ordinary rating for most 3 phase) and use the gears just like you would w/o the VFD.  I've done countless hours of research and to date, that is the most bang (no pun intended) for your buck.  I also am seriously contemplating the use of the braking resistor for safety reasons.  Back in the day when running a line making precision production parts for an auto manufacturer, I have seen what can happen when things go sideways...  Sometimes, you need things to stop like RIGHT NOW.  Lol
> I like the idea of a fan set up for maximum cooling when turning at lower speeds.  In my research, I have learned that some (if not the majority) have experienced some higher motor temperatures when making deep cuts at lower cycle speeds, this may help with that?
> I'm certainly not an electrician, I'm simply researching machines and setups that will best fit my needs in the future.  I hope folks don't think I'm trying to hijack the OP, it is not my intention, I'm just trying to bring what I have found to the table in hopes of either confirmation or critique, who knows, maybe it will help someone else!?
> ...


NoSquib,  and others ...
The braking resister absorbs the energy in the system, but as thing slow down, the voltages are less, and so less energy is absorbed.  This is demonstrated on one of the youtube videos:  It takes seconds ... I think it took 7 seconds for a lathe to stop using the braking resistor.  It's on the web.  Another guy on the web put a disk brake on his mini lathe.  I am now going to go see if there is any discussion of a brake for the 1340. 

I read somewhere on hobby-machinist recently (within the last week) two people talking about installing braking resistors.  I wonder if they are will ing to post time it takes from some RPM to stop.

My apologies to the owner, moderator of this thread, if my postings ought to go elsewhere.


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## wrmiller (May 4, 2015)

I am putting a 50 ohm/500w braking resistor on my 1340GT and will use the programming of another member here to do a tw0-stage braking: Normal braking will be about 1 second, and this will be fine for the stock chuck at any speed and larger chucks like my PBA at slow speeds. When running my 8" chuck above 1000 rpm, I will engage the second braking algorithm which Mark as proven to stop the larger chuck in about 2-3 seconds.


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## GA Gyro (May 4, 2015)

I have a braking resistor to mount on mine also... a 35 ohm/500W.  

As I understand (reading at this forum), one can stop the lathe in 1-2 seconds (maybe not with a big heavy chuck), or a bit longer.  

My plan is to set it up with the normal stop to run 4-5 seconds... and the E stop to really clamp down.  

I suspect repeated quick stops (1-2 seconds) may not be the best for the motor or gearbox... and not really necessary most of the time.


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## wrmiller (May 4, 2015)

Not any harder than starting a 6" chuck at 1800 rpm with a single phase motor, which is what the lathe is configured to do from the factory.


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## NoSquib (May 4, 2015)

JPH said:


> NoSquib,  and others ...
> The braking resister absorbs the energy in the system, but as thing slow down, the voltages are less, and so less energy is absorbed.  This is demonstrated on one of the youtube videos:  It takes seconds ... I think it took 7 seconds for a lathe to stop using the braking resistor.  It's on the web.  Another guy on the web put a disk brake on his mini lathe.  I am now going to go see if there is any discussion of a brake for the 1340.
> 
> I read somewhere on hobby-machinist recently (within the last week) two people talking about installing braking resistors.  I wonder if they are will ing to post time it takes from some RPM to stop.
> ...


You are correct BUT, the GS2 (only one I'm familiar with) is programmable.  You can make it take several minutes to a couple of seconds.  I'm sorry, but I do not have formula's on spin down time.  I BELIVE it's going to be dependent on the force of the spindle, weight, resistance applied from the resistor, etc...  This is a lot of the equation that I'm not greatly informed on.  I went to youtube.com and typed "GS2 VFD" in the search, there are several different applications that show the vfd before programming (ramp up, ramp down, etc) and after.  The thing I have yet to see, is that particular VFD actually using the resistor.  





at the 12:30 mark he discussed the ramp down programming (I know, not the GS2, but this is a series I keep up with and could find quickly).  If I'm not mistaken, bluehands (previous youtube I posted) actually programs the GS2.

I dunno, I think we're all agreeing?!  I got on a fact finding spree and lost my vision...  lol  Hope I've helped at least point people in the direction for sources.


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## Dman1114 (May 4, 2015)

I have the GS2 on my Grizzly g4003g... newly installed....

I didn't have a break resistor for a couple days ... was in the mail on its way.    anyhow

i found it would stop the chuck from all speeds within 2 secs...  if programmed...  but at 1400 + Rpms   with my 6" 6 jaw and a piece of 2 inch aluminum in the jaws.  at anything under 1.8 sec breaking time it would over load and i would get an error....


Went on eBay and found me the proper size breaking resister for like 30 bucks....

now it stops at 1 sec no problems... and that is fast.    I don't dare set it to stop any quicker.

Breaking resisters are cheap...  no reason not to get one unless you don't need to stop fast.


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## NoSquib (May 4, 2015)

Dman1114 said:


> I have the GS2 on my Grizzly g4003g... newly installed....
> 
> I didn't have a break resistor for a couple days ... was in the mail on its way.    anyhow
> 
> ...


Great!  Thanks for sharing.  Being as I do not actually have one in front of me to play with, it is great that you do and were willing to share the results.  That should clear the murky water for us!  And for what it is worth, I completely agree, when I worked at ______ company, we did not have a braking mechanism, and, at times, you simply stood back and waited for it to stop slinging parts/tools before you approached.  I'm with you, when I order my lathe, I will have a braking (I think we've been crossing up the spelling  ) resistor.


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## Dman1114 (May 4, 2015)

The GS2 manual is pretty good...   I got some pointers from another member here.... but the manual tells you what size to get.   I just got on eBay and searched for one that size.... 300w 70 ohm

i went with the 3hp GS2   here is a link to the resistor...

very easy to install...

just bolt it to the cabinet n plug and play  2 wires


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## JPH (May 4, 2015)

wrmiller19 said:


> I am putting a 50 ohm/500w braking resistor on my 1340GT and will use the programming of another member here to do a tw0-stage braking: Normal braking will be about 1 second, and this will be fine for the stock chuck at any speed and larger chucks like my PBA at slow speeds. When running my 8" chuck above 1000 rpm, I will engage the second braking algorithm which Mark as proven to stop the larger chuck in about 2-3 seconds.


That's very good to hear, since I'll be following in that direction.  Your postings have been very helpful in my making up my mind.  Keep up the informative posts.  Thank you.


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## JPH (May 4, 2015)

Dman1114 said:


> I have the GS2 on my Grizzly g4003g... newly installed....
> 
> I didn't have a break resistor for a couple days ... was in the mail on its way.    anyhow
> 
> ...




One second.  Fantastic.  Thanks for the specific info.


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## mksj (May 4, 2015)

As others have outlined, a braking time of 1-2 seconds is feasible when using a braking resistor, I see no reason not to use one if your VFD dose not require a braking module (which can be expensive). Since there are different VFD inputs and programming, there are many possibilities how to  program and engage different braking times. The bottom line, you can stop a chuck very quickly without having to jump on a foot brake. One must be realistic as to the stopping time as the speed and the weight increases. I can say that the WJ200 with the brake resistor, will stop a 60lb chuck at 1200+ RPM  in about 1-2 second without fault. Some of the other VFDs will fault out, even with a brake resistor, so not all VFDs are created equal.

Low speed cooling of motors varies by type and how it is made. A heavy cast iron motor with higher temperature insulation can tolerate more extreme operating ranges. With a manual lathe, you are not operating the motor at full load continuously, so overheating is unlikely with a well built motor. Still heat will shorten a motors lifespan, the question is will it be an issue in your case. Most likely not. Some motors include thermal switches that can be connected to the VFD and will cause a fault. A TENV motor will run cooler at low speed.

Below is a comparison of heat build up at different VFD frequencies for Marathon motors of various enclosures. The graph would infer that TEFC can run at fairly low RPMs and still be in a safe operating temperature range without external cooling. This mostly applies to newer motors with higher temperature ratings for their insulation. If you have a 6 speed gearbox version of the PM1340GT, I can see no reason to operate it at very low Hz  under high load for an extended period of time. This probably is a bigger issue with 2 speed range lathes that usually operate the VFD/motor over a 10 fold speed range. In many cases the motor is oversized.


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## NoSquib (May 10, 2015)

Stumbled across this tonight.  Good one that will answer some questions here.


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## stevemetsch (Aug 17, 2015)

mksj said:


> If you buy the 3 phase PM1340GT, you only have the expense of the VFD and a few electrical components to convert it, so maybe $250 in total.  Although the the Hitachi WJ200 is what QMT usually bundles with the machine,  something like the TECO JNEV-202-H1 will work just fine and they run about $180. http://dealerselectric.com/JNEV-202-H1.asp
> 
> The PM1340GT motor space is very compact, so replacing the stock 1 phase motor with a 3 phase, you have very few options and will at least double the cost. The conversion to VFD is not necessarily difficult, there are different options of how to implement it. Some people keep the stock 240VAC to 24VAC transformer to power the light, but remove the contactors, relay and board wiring. You retain the wiring to the direction controls. You install a single 4 pole relay on the main board and wire everything up. See attached file with a suggested schematic and approximate parts costs. I would not use input 4 for 2 stage breaking, but others have requested it. The VFD control connections are all low voltage, it does require some reconfiguration of the front panel switches which is easily accessed.
> 
> ...


I just got my new PM1340GT in the shop and due to blissful ignorance exaggerated by optimism I have a 3/4 ton decoration until I get the VFD installed. I am looking for a simpler version of the schematic by mksj. Is it possible to run my 220V to the VFD and then the three wire+G to the motor.
Then run another 220V to one of the existing contacts that power up the 24V transformer. Use that 24V to power the existing controls and feed theitr "output" to the VFD. 
I am not understanding why there is a NEW low voltage relay in the schematic.
I may just be cheap, but I don't like to have lots of parts left over because i HAVE to save them all.


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## mksj (Aug 17, 2015)

I did consider this when I first was installing my VFD. The controls operate the two contactors. They also use another DC relay as a power start up relay. It just got a bit challenging figuring out all the wiring to get it to work correctly.  It is possible to strip L1-L3 wires from both contactors and use one contact on the  forward/reverse contactors wired to the VFD control circuit to control the 24VDC to the VFD inputs. The Jog is a bit problematical because it requires both a JOG command and a direction command to be inputted at the same time. So you would probably need to use a 2 pole switch on the front panel to operate the direction control contactor and a second independent switch to send a 24VDC signal to the JOG input on the VFD.  Not sure how the rest of it will work, but I did something similar to this with the PM1340GT control board that I ended up using in in a bandsaw conversion to low voltage contols.  I did another build trying to pass through the signal VFD 24VDC  via contactors and they ended up being unreliable (not sure why, but they ran off of 120VAC). I believe it was an issue of getting the relay to latch correctly.

The single 4 pole relay  is inexpensive, simple and works well, you strip out the contactors and origional 24VDC power relay. It only works in this configuration with the WJ200 because it can supply 24VDC at 100mA for the control inputs. The JNEV, will not work as well as most other VFDs. If this is what you have, you can try the contactors, I have also built relay control systems for others that use a separate DC power supply. You could reuse some of the controls switches and the transformer to power the light, but not the power indicator light because it draws too much current and you still need a speed control. There are a lot more control configurations possible when going to a dedicated 24VDC control system (I am doing a more complex version per their specifications for another forum  member currently), but whatever works is fine at the end of the day.


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## stevemetsch (Aug 18, 2015)

mksj said:


> I did consider this when I first was installing my VFD. The controls operate the two contactors. They also use another DC relay as a power start up relay. It just got a bit challenging figuring out all the wiring to get it to work correctly.  It is possible to strip L1-L3 wires from both contactors and use one contact on the  forward/reverse contactors wired to the VFD control circuit to control the 24VDC to the VFD inputs. The Jog is a bit problematical because it requires both a JOG command and a direction command to be inputted at the same time. So you would probably need to use a 2 pole switch on the front panel to operate the direction control contactor and a second independent switch to send a 24VDC signal to the JOG input on the VFD.  Not sure how the rest of it will work, but I did something similar to this with the PM1340GT control board that I ended up using in in a bandsaw conversion to low voltage contols.  I did another build trying to pass through the signal VFD 24VDC  via contactors and they ended up being unreliable (not sure why, but they ran off of 120VAC). I believe it was an issue of getting the relay to latch correctly.
> 
> The single 4 pole relay  is inexpensive, simple and works well, you strip out the contactors and origional 24VDC power relay. It only works in this configuration with the WJ200 because it can supply 24VDC at 100mA for the control inputs. The JNEV, will not work as well as most other VFDs. If this is what you have, you can try the contactors, I have also built relay control systems for others that use a separate DC power supply. You could reuse some of the controls switches and the transformer to power the light, but not the power indicator light because it draws too much current and you still need a speed control. There are a lot more control configurations possible when going to a dedicated 24VDC control system (I am doing a more complex version per their specifications for another forum  member currently), but whatever works is fine at the end of the day.


Thanks MKSJ,
I think this helps.  I am understanding that I need to limit the VFD 24V to 100 ma.
So I need to use a separate power source for the work light (I can put a 120V to 24V xfrmr in line with a 120V wall plug ).
AND  Change out the "Power" light  to an  LED that will work on 24V.
These two changes will let the VFD operate the controls except that the jog function may not work properly or will need to have a SPDT switch added to select Fwd or Rev.
If this is all wrong I will hire you to draw me a schematic.
BTW I have Hitachi WJ2000-15SF shipped with the lathe from PM and am plugging into 240V 1 phase.
Steve


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## mksj (Aug 18, 2015)

Hi Steve,
I am not quite sure about how you want to setup your system. If you try to make it work with the current contactors and main 24VAC power transformer, you just need to stripout the L1-L3 contactor power wiring and then use the contacts on the forward contactor say L1 to control the VFD forward input, and likewise on the reverse contactor. The attached picture, shows the general high voltage black wiring that would need to be removed, including the thermal overload switch, 220V would be connected directly to the transformer, and the blue lines would be for/rev connections to the VFD.  You could do this and see if the contactors work as expected, I can then draw you a simple connection diagram for the jog to work, but you will need a different switch. The problem is you really need to know what your doing and where all the high voltage and low voltage connections go, otherwise it could be very dangerous. I do not mean to be draconian about this, but it is part of the reason I usually suggest stripping all the old relays/wiring an using  a single 4P relay. Only if you go with the single 4P relay, that is powered by the VFD, do you need to worry about the total power drain for the VFD 24VDC system. You can still keep the main VAC power transformer in either case to power your light, which is 24VAC.

If you want, you can PM me your email and I can try to provide some additional information or a possible schematic offline. I am not hired, but I try to help others as best as possible. I have a good understanding of the control/VFD system only by learning, my professional background is medicine. 
Mark


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## stevemetsch (Aug 19, 2015)

mksj said:


> Hi Steve,
> I am not quite sure about how you want to setup your system. If you try to make it work with the current contactors and main 24VAC power transformer, you just need to stripout the L1-L3 contactor power wiring and then use the contacts on the forward contactor say L1 to control the VFD forward input, and likewise on the reverse contactor. The attached picture, shows the general high voltage black wiring that would need to be removed, including the thermal overload switch, 220V would be connected directly to the transformer, and the blue lines would be for/rev connections to the VFD.  You could do this and see if the contactors work as expected, I can then draw you a simple connection diagram for the jog to work, but you will need a different switch. The problem is you really need to know what your doing and where all the high voltage and low voltage connections go, otherwise it could be very dangerous. I do not mean to be draconian about this, but it is part of the reason I usually suggest stripping all the old relays/wiring an using  a single 4P relay. Only if you go with the single 4P relay, that is powered by the VFD, do you need to worry about the total power drain for the VFD 24VDC system. You can still keep the main VAC power transformer in either case to power your light, which is 24VAC.
> 
> If you want, you can PM me your email and I can try to provide some additional information or a possible schematic offline. I am not hired, but I try to help others as best as possible. I have a good understanding of the control/VFD system only by learning, my professional background is medicine.
> ...


Thanks,
I will study the photo tomorrow. This evening I ran 220 V to the VFD and connected the motor leads to the VFD. it lit up and acted OK, but I don't know how to make the motor run. I will study teh book and then work out the controls. 
Thanks for all your help.


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## mkbuildit (Yesterday at 6:45 PM)

Reading these old threads has been a huge help! I have a Gs2 VFD and a 1440 3ph lathe I am working to sync up. Did you complete the conversion? How has it been working?


Sent from my iPhone using Tapatalk


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