What variable frequency drive.

S

swa

Guest
I have a Logan 11" and was looking at getting a VFD. The lathe motor is a 3/4hp. I here that the older motors don’t hold up well to the VFD as the winding insulation is not adequac enough or something. So I need some help from the pros what vfd do you recommend?
Please help...

Thanks in advance!!!!
Chris
 
I would do like Mike Bryant did on his Jet. He bought a Baldor motor that was designed to go with his frequency drive.
Butch
 
Lesson also makes a motor and drive for VFD. Just in case you want to buy locale there is good support. I've ad Baldor fail me on a few occasions, however they make a good product.

If you do a web search on VFD drives and motor, you can find deals. Remember to help keep the cost lower, you don't need mush horse power for smaller lathes. 3/4 hp is about the top.
 
VLDs

I bought a Westinghouse FM-100-215 and am running a 5.5 hp 3phase motor. If you will go over to Home Shop Machinist or the Popular Machinst boards they will have threads specific to VFDs. Dealers Direct has some great deals on VFDs.

Nat Lambeth
 
I bought the same Westinghouse/TECO VFD that Nat mentions to run a 3hp motor on a Jet lathe, and have had nothing but good experiences with it. So, when I purchased a 2nd lathe, I started looking for another FM100-215.

What I was told was that the advances in drive technology have been ripping right along, and that the FM100 series drives were actually obsolete when I bought mine about three years ago. Drives Warehouse recommended a Hitachi SJ200 series drive, and I've been just as pleased with it as with the TECO.
 
I have used Hitachi VFD drives more than any other brand and have to say they are the best, not all un-complicated however, on the bigger drives you sure need to understand the failure codes.
 
swa said:
I have a Logan 11" and was looking at getting a VFD. The lathe motor is a 3/4hp. I here that the older motors don’t hold up well to the VFD as the winding insulation is not adequac enough or something. So I need some help from the pros what vfd do you recommend?
Please help...

Thanks in advance!!!!
Chris
Click to expand...

Chris,

I am about as far from a pro as you can get, but I have been very pleased with the Hitachi SJ200 for the 1 HP motor on my Heavy 10.

I mounted the VFD on the wall away from the chips and liquid of the lathe, and originally planned to use the removable control panel with a cable to put the controls in a handy position. After pricing the cable I decided to wire up my own controls. I used a project box from MCM Electronics, plus a rotary control, and a three position forward/stop/reverse switch, and wired it to the Hitachi per the instruction book. This works great, and is right at hand.

I don't know how old my motor is, but it seems to not be showing any ill effects from the VFD.

Jim

VFDcopy2.jpg
 
VFD 3 phase..

Be advised a VFD is not a rotary converter. It turns AC into DC and back into 3 phase AC. The juice it spits out is true 3 phase current. The better VFDs allow one to program in a number of features that are available with 3 phase current. The biggie is Varible frequency that allow one to regulate the frequency. This allowe one to run motors faster or slower. The old frequency drives were not computer controlled and allowed the motors to loose torque as the frequency was lowered. This has been corrected with the new solid state VFDs they can agg amperage to adjust for the frequency reduction in the voltage keeping the modern motors from loosing torque. The VFD can be used to brake your motor if programed to do so. It can also be programed to adjust the starting or stopping speed keeping from having a jumpy lathe.

I would not trade my VFD for real 3 phase current from the power company.

It works great running a tig welder that operates off of 3 phase current.

Nat Lambeth
 
The main thing that makes a difference on a motor designed for use with a VFD is that it's two motors in one. They have a separate motor that runs a constant velocity fan that cools the main motor no matter what speed the motor is turning. This lets you keep the motor cool while it's running slower speed than what the motor would normally be rated. If you try to do this with a normal motor, the fan speed to cool the motor slows down as the motor speed slows down.

The VFD that I had on the Jet was a Hitachi. The VFD that came on the Kent lathe that I now have is a Yaskawa Varispeed G7. I'm running 3 phase into the VFD and 3 phase out. Fortunately, my shop is next to a 3 phase line and I paid to have another transformer set up years ago before SPS sold out to Xcel Energy. I don't know whether they would have done it now or not. At the time, it cost a little more than a phase converter to have the second transformer hung and a 3 phase meter installed.

If you're running single phase current into the VFD, they say you want a VFD rated for 1 hp more than what your motor rating is. If you're running 3 phase into the VFD then the VFD can be rated for the same horsepower.

Being able to twist a knob and go up or down on rpm on the lathe will certainly spoil you and will also save you time.
 
New VFD vs older VFDs

As Mike stated the old rule was to buy a VFD rated 30-50% more horspower than you were going to run. I was told by an electrical engineer an a VFD manufacture that the new VFDs are rate differently today and the horsepower ratings are now 1:1. I also was told it is always better to have a VFD that is rated higher than the expected amperage.

I can say my lathe came with a Chicom 3 hp motor. The correct footprint and shaft diameter American motor was a 5.5 hp motor. It barely fits but it fits and it has run without any problems for 6 years.

Nat Lambeth
 
Last edited:
V f d

I have a brand new WEG VFD rated for up to 1 HP
Was going to use it for a milling machine but went a different route.
E -mail me if interested at
kasjaka@gmail.com
 
Thanks for all the input. As to another question, I have an older motor (Doerr electric motor), Not sure of age but was very lightly used and it looks brand new. Can I run a VFD on this motor or do I need a newer motor?
 
The motor has to be 3 phase to be run with a VFD. If your Doerr is 3 phase, it will work, single phase it won't. If you're concerned with keeping the motor cool when running at slow speed, you can always add on an external cooling fan to cool down your motor.
 
Yes my motor is a 3 phase. Thanks my concern is about the motor running at all on the VFD. Im glad to here it will work. thanks again. Also Per the two VFD I was looking at are Hitachi X200 and the SJ200. They are both 3hp 230volt 1 or 3 phase in 3 phase out. The only difference that I can see is that the SJ200 has a protected chassis enclousure and the X200 has the IP 20 enclosure. Witch one do you all think is a better choice? My motor is a Doerr ac 230 volt 3/4 hp motor. Thanks again for all advice!!!!



SWA
 
One of mine is the hitachi SJ and it has been with me 6 yrs. on my mill. My mill has the old fashion factory Bridgeport motor. I run it from 20hz to 90 hz. The SJ actually has too many programable features in my opinion.
Butch
 
I have at least seven inverters ranging up to seventy five h.p. The only problem I have had with them is voltage spikes when the power company changes grids.They will shut down if a voltage spike occurs after trying to auto restart three times. The solution was to add isolation transformers and line reactors, because the drives were going 24/7. For machinery that is attended and only used occasionally I would not go to the added expense.
 
VFDs and motors

I don't know about VFDs running lathes but I do know about VFDs running large pieces of equipment and perhaps some of the same issues apply.

There are inverter duty motors that can be fine tuned to the inverter that is matched to them. The better inverters have a feature, programmed in, that allows the inverter to 'read' vital electrical characteristics of that specific motor and adjust the inverter's control parameters to match. The result is a 'matched pair' of components that operate in electrical harmony with each other. Bear in mind this occurs when the motor is rated 'inverter duty' and the inverter has that specific function. The better inverters also have a diagnostic program built in, allowing the operator to determine the cause of faults or trips.

Lou Baccino
 
You must log in or register to reply here.
Back
Top