Pm 1340 Gt Vfd Question

[spring5497]

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.

 

[Karl_T]

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.

 

[mksj]

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.

 

[mksj]

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).

 

[spring5497]

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?

 

[mksj]

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.

 

[GA Gyro]

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!

 

[jds]

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

 

[coolidge]

Did someone say Haas TL2?

 

[GA Gyro]

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...