PM1440GT

[ColbyB99]

Any help will be greatly appreciated.

 

[davidpbest]

Hey Everyone, I'm new to the site. I'm still trying to figure how to properly get around in here. I just purchased a PM1440GT. The wait was a killer. Looking for some people to give recommendations for a couple upgrades

I can help you. What are your questions about? DM me if you'd like. The attached might be of service but is not specific to the 1440GT.

 

[ColbyB99]

Hello, thanks for the quick response.
I purchased the single phase version due to not wanting to have to be constrained to installing a vfd for the 3 phase conversion. At the time I didnt see having that would be necessary. However, I would like to have a vfd for my lathe, mainly to use as a soft start and have the ability to control the frequency for variable speed if I'd want to.

My question is, has anyone tried this on a 1 phase 1440gt lathe and how did it work out.

I see a lot of post on here for the 1 phase to 3 phase conversion but not having a 1 phase vfd driving a 1 phase motor. I asked some techs at PM and they directed me here

I have experience with vfd's to servos to industrial robots like fanuc and nachi but not lathes and definitely 1 phase vfd's. Everything I work around is 480v 3 phase when it comes down to motion control.

I'd like to know if it's worth it trying a 1 phase to 1 phase vfd or buying a 3 phase motor to install with a single phase to 3 phase vfd conversion. I'd hate to buy a single to single vfd and it not work out and turn around and have to buy another to convert to 3 phase along with the motor.

Again I'm a novice to machining but i have 10+ years in the technical field primarily robotics, electrical/ electrical safety control systems. PLC programming and pretty much everything in between. So setting this up should be no problem I would like to hear some input on the above.

Thanks again

 

[davidpbest]

The single-phase motor with your 1440GT is not inverter grade and this can not be controlled with a VFD. In order to use a single phase motor with a VFD, the motor must be inverter grade, which means paying to have the existing motor rewound and you might still have issues with overheating at low RPM. Purchasing a new motor will be a lot less trouble and expense. I suggest you review this thread if you want to swap out the motor for 3-phase.

1440GT Upgrades and Additions

Part One, VFD Conversion: As some of you may remember I had a 1340GT on order for many months and ended up finding a deal on a used 1440GT just before my 1340 was to be delivered. The thread with that story is here: https://www.hobby-machinist.com/threads/my-1340gt-story.95922/ Since...

www.hobby-machinist.com

 

[mksj]

There are some VFD's that can be used with single phase motors, they require direct wiring to the motor coil and start coil but I have no experience using them. Since the coils are at 90 degrees and not symmetrical, I would expect the power delivery to be somewhat lumpy and would be doubtful that the motor will maintain constant torque below its base speed. The main applications are variable torque applications like fans and pumps. All the people I have worked with adding a VFD on a single phase machine have switched out the motor to 3 phase. There are no mainstream VFD manufactures that I am aware of that make VFD's for single phase motors, and most are expensive for what you get. If you can get a stock 3 phase 1440GT motor that might be the least expensive and simplistic option not requiring a new motor mount. Most of these smaller Asian lathes are very limited to a replacement motor that will fit in the space/mount. If you are going through the time and investment to go with a VFD system, in this case the motor should be switched out. There is some guidance on a basic VFD install for the 1440GT, but it is not recommended with used contactors as they are not suitable for low level VFD signal controls. As David indicated, also JBOLT and few others have additional information on switching the single phase 1440GT to a VFD with 3 phase motor.

VFD’S for Single Phase Motors?

www.wolfautomation.com

 

[jbolt]

My question is, has anyone tried this on a 1 phase 1440gt lathe and how did it work out.

I did a conversion from single phase to 3 phase. A few others here who have done as well. There are also a few who changed out the factory 3hp 3ph motor because they would not play nice with the VFD.

The biggest hurdle I had was finding a motor that would fit. The factory 3hp 3ph motor is the same size as the 2hp 1ph. Every 3hp 3ph motor of the same diameter of the factory motor I could find was too long to fit. I finally found a Marathon E470 3hp 3ph motor that was short enough but it has a larger diameter. I had to make a new motor mount and modify the end cover to get it to fit. Also needed a new motor pulley.

Super happy with the conversion. The marathon motor is a beast.

I posted on this here.

 

[ColbyB99]

Ok, this is the kind of stuff I wanted hear based on my lack of knowledge for 1 phase setups. So I saw in the thread where the guy used a marathon motor that would barely fit and needs mods to be able to mount it. Will the motior that comes with a 3 phase 1440gt 3 phase motor be a good canditate(since it should direct fit) or do I need to use a different motor all together for optimal results. Also I'd like something that will fit with little to none mods on the mounting and belt alignment/adjustems.

I'm trying to keep cost as low as possible, so if I can save here and there to save money, I'll be able to spend that on tooling. Remember I have little to no tooling. Just enough to to chanber, thread, and fit a rifle barrel.

Also, how can i reach Mr. Jacob's or anybody else here for a list of highly recommended parts, setup, and also vfd parameter settings. I will pay extra for quality parts that also help to eliminate modifying my lathe to accommodate the motor. I will build a housing for the vfd separately from my other controls so that I'm good with.

Something told me in the back of my mind to go with the 3 phase lathe and install appropriate controls. It's just one of those hard lessons learned and is paid dearly. I just never assumed I would not need a vfd as there are plenty of speed ranges on the lathe and didnt know that s soft start would be handy.

Last question, I am mainly wanting a soft start function. The variable speed is just luxury at this point . Currently when I am in low range up to higher end of mid range, when I start my lathe it starts abruptly, harshly, and just down right sounds no good. What would be everybody's thoughts on adding a soft start controller to combat this harsh startup.

Thanks guys,

I did a conversion from single phase to 3 phase. A few others here who have done as well. There are also a few who changed out the factory 3hp 3ph motor because they would not play nice with the VFD.

The biggest hurdle I had was finding a motor that would fit. The factory 3hp 3ph motor is the same size as the 2hp 1ph. Every 3hp 3ph motor of the same diameter of the factory motor I could find was too long to fit. I finally found a Marathon E470 3hp 3ph motor that was short enough but it has a larger diameter. I had to make a new motor mount and modify the end cover to get it to fit. Also needed a new motor pulley.

Super happy with the conversion. The marathon motor is a beast.

I posted on this here.

Thanks for the reply,

I guess that's what I'm running into right now is finding a compatible motor that doesn't require many mods to my lathe to get it to fit.

I mean if I have to make some minor mods to get it to fit, then that's what I'll have to do. Anybody else know of any motors that will work for what I need or where I can get one.

Thanks,

 

[jbolt]

I guess that's what I'm running into right now is finding a compatible motor that doesn't require many mods to my lathe to get it to fit.

I mean if I have to make some minor mods to get it to fit, then that's what I'll have to do. Anybody else know of any motors that will work for what I need or where I can get one.

Look at the motor plate for the frame size. Then search for motors of that frame size. I suspect you will only find 1.5 or 2hp motors that might fit.

The PM 3ph motor, which is the same frame size as the 1ph 2hp, is listed as 3hp. Personally I find it difficult to believe that the motor is actually 3hp based on the extensive searching I did.

Here is a video someone did of the factory 3ph motor issues.

Here is after their conversion to the E470.

Ebay can be a good source for motors at discounted prices.

 

[ColbyB99]

Look at the motor plate for the frame size. Then search for motors of that frame size. I suspect you will only find 1.5 or 2hp motors that might fit.

The PM 3ph motor, which is the same frame size as the 1ph 2hp, is listed as 3hp. Personally I find it difficult to believe that the motor is actually 3hp based on the extensive searching I did.

Here is a video someone did of the factory 3ph motor issues.

Here is after their conversion to the E470.

Ebay can be a good source for motors at discounted prices.

So that being said. Would a 2hp 3phase motor be ok since my current motor is 2hp I dont see it making any difference. I am seeing a great deal of those for a decent price.

 

[mksj]

The issue of a replacement motor is one of size, other than the one that comes with the lathe I have not seen a 3Hp 1800RPM in a 90L motor frame. Most 2Hp motors will be too long, the electrical box will be in the wrong direction, and none will be a drop in replacement as far as mounting. The stock 3-phase motor is a 90L 1800 RPM, and I do knot know if the motor shaft diameter is metric or inch (my 1340GT was a metric frame with an imperial (inch) shaft size. So it is very likely you will also need a new pulley, not a big deal. So you need to measure up the motor dimensions and find something that is close or see if you can buy a replacement from QMT. Other than the Metric motors in a 90L frame that the electrical box position can be changed, and is short enough, nothing is going to fit. A 3Hp will give you a wider operating range off of the VFD, but a decent inverter/vector type 2 Hp motor would also work well (but not something you find in metric sizing). Length of the motor and the electrical box location, I do not know of any replacements that would work as a drop in,

When it comes down to a replacement, really only 2 options which is the stock 3 phase motor or the Marathon E470 with a different mount.