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Single phase to 3 phase conversion on Modern GH1440W lathe
- Thread starter John Conroy
- Start date
Good eye Craig, I have developed weird sleep habits since I retired! My wife was beginning to wonder if the lathe would ever work again and I underestimated how long it would take me to get this done. Since I started last Friday, I have probably spent 50 hours in the shop working on this and another 8 hours reading the VFD manual and making notes. I have to say It is hard to believe you can buy a piece of equipment as sohisticated as this VFD for $350. But as of 8pm Wednesday, it lives! I will post a link to a video I shot after working 10 hours on it yesterday and seeing it run for the first time, I was a little spaced out. I wound up with a more complicated wiring configuration than I thought with 3 control input cables running from the front switch panel directly to the VFD and another 4 from the factory junction box on the back of the machine to the VFD for a total of 7 cables running to and from the VFD enclosure. From the original elecrical content I re-used the main contactor, the transformer that steps down the 240 to 120 volts ac and 24 volts dc, 2 DIN rail mounted fuse holder, the main bus bar and some cable. I could have managed with fewer cables, I used 24 guage cat 5 with 4 twisted pairs in each cable for the controls but the motor and VFD are a very electrically noisy environment and I wanted to seperate most of the inputs to reduce the chance that EMI would create control problems. Power to the VFD and the motor is through 12/3 cable. I bought the VFD enclosure, the fan and it's power supply, the cable glands the potentiometer and all the terminal ends on Amazon so I could avoid exposure to other people. Of course I wound up with more of some of that stuff than I really wanted, 20 Potentiometers and 50 cable glands but such is the nature of online shopping. I am impressed with how fast Amazon can deliver, I orderd the enclosure at 8pm on Sunday and it arrived at 3 pm Monday.
I mounted the enclosure so that the digital display on the VFD is visible through a 3 inch window I cut in the front and I also cut two 4 inch holes in the sides for the fan and outlet air grills. Only 2 of the cable knockouts were the right size for the cable glands I bought so I had to drill some extra holes in the bottom of the box and weld 3 washers on to size the knockout holes that were too large. The box it 10 X 10 X 6 inches.
Here are a few pics, I will post a link to the vid after I upload it to YouTube.
I mounted the enclosure so that the digital display on the VFD is visible through a 3 inch window I cut in the front and I also cut two 4 inch holes in the sides for the fan and outlet air grills. Only 2 of the cable knockouts were the right size for the cable glands I bought so I had to drill some extra holes in the bottom of the box and weld 3 washers on to size the knockout holes that were too large. The box it 10 X 10 X 6 inches.
Here are a few pics, I will post a link to the vid after I upload it to YouTube.
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That looks awesome John. Good job!
I'm pretty sure you could write a #1 bestseller How-to manual & re-coup your VFD expense. But you probably are itching to get back to work!
Hope you kept lots of pics & notes, suspect others will follow now that you've blazed the trail.
Just to clarify, did you do the motor/vfd package scoping out on the main (USA) link you provided & they shipped to Edmonton, or Edmonton just happened to have what you were after?
I purchased a Teco-Westinghouse motor and compatable VFD online and picked up at the Edmonton Teco-Westinghouse warehouse the same day.
I'm pretty sure you could write a #1 bestseller How-to manual & re-coup your VFD expense. But you probably are itching to get back to work!
Hope you kept lots of pics & notes, suspect others will follow now that you've blazed the trail.
Just to clarify, did you do the motor/vfd package scoping out on the main (USA) link you provided & they shipped to Edmonton, or Edmonton just happened to have what you were after?
I purchased a Teco-Westinghouse motor and compatable VFD online and picked up at the Edmonton Teco-Westinghouse warehouse the same day.
Thanks guys.
Johnwa, for now the schematic only exists in my head but I plan to make one and note all the programming details.
Dabbler, my mill VFD wiring is pretty cobbled together also. I decided to do this one better because I have lots of time and this lathe is a new machine.
Peter, I dealt with EMotorsDirect.ca, the Canadian version. I think they drop ship direct from the vendors who have warehouses all over the country. They offer free pickup if they have a warhouse in your area. This is the motor I bought, it shows stock in Calgary so they must warehouse there too.
https://www.emotorsdirect.ca/item/teco-pdh0034
This is the VFD I bought, it is the most simple one they sell and only available for motors up to 3HP. Corey, the sales guy I dealt with recommended it because it's the easiest to set up and program. The programming is very similar to the Huanyang on my mill. I think the Huanyang is a clone of the Teco.
https://www.emotorsdirect.ca/item/teco-l510-203-h1-u
Johnwa, for now the schematic only exists in my head but I plan to make one and note all the programming details.
Dabbler, my mill VFD wiring is pretty cobbled together also. I decided to do this one better because I have lots of time and this lathe is a new machine.
Peter, I dealt with EMotorsDirect.ca, the Canadian version. I think they drop ship direct from the vendors who have warehouses all over the country. They offer free pickup if they have a warhouse in your area. This is the motor I bought, it shows stock in Calgary so they must warehouse there too.
https://www.emotorsdirect.ca/item/teco-pdh0034
This is the VFD I bought, it is the most simple one they sell and only available for motors up to 3HP. Corey, the sales guy I dealt with recommended it because it's the easiest to set up and program. The programming is very similar to the Huanyang on my mill. I think the Huanyang is a clone of the Teco.
https://www.emotorsdirect.ca/item/teco-l510-203-h1-u
Today I got the lathe put back in place and levelled again. I left it about 6 inches further from the wall than before so I can get the rear electrical door open if needed. Then I cleaned up the whole garage/shop as it had become quite a mess in the last week. I played around with accelleration and decelleration times. Since this model VFD can't be fitted with an external braking resistor you have to program to the limitations of the vfd. With my heaviest chuck installed I tried setting decel to 3 seconds from the factory default of 10 seconds but from 1800 rpm the vfd would display an over current trouble message. I settled on 5 seconds as it reliably stops with no faults from that speed with no fault message. I also played with the wide range of speeds available now. I will be changing gear ratios alot less now. Most of the time I'm working between 200 and 1200 rpm. If I leave it the 1200 rpm gear, at 10HZ it turns 192 rpm so just that one gear will do for most of my work.
I shot a couple of quick vids. In the first one the machine sounds really loud but it's because the camera is sitting on top of the gear box. Doing math in my head didn't work out too well either, 15HZ is about 300 rpm not 500.
I shot a couple of quick vids. In the first one the machine sounds really loud but it's because the camera is sitting on top of the gear box. Doing math in my head didn't work out too well either, 15HZ is about 300 rpm not 500.
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Here's a quickly drawn schematic. I will detail programming tomorrow.
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I found that the 2 page quick start guide does an excellent job showing you how to use the keypad and display to program the drive and gives examples of the most commonly used parameters so you can easily be up and running in just a few minutes after the wiring is done. There were just a few more advanced settings based on info I got from the Clough42 videos and dealing with the normally closed switch on the chuck guard. Here is the quick start guide and my set up.
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Bravo. The VFD certainly gives a wide speed range. That slow tickover is insane. What are your thoughts on "one gear complacency syndrome" LOL. Maybe install an rpm display so you basically ignore the frequency, turn the number to whatever rpm makes sense but allows you spread the gear selection around a bit?
My temporary solution to the motor extra width was to cut a hole in the cover. I have ordered a fan and enclosure from Amazon. My plan is to mount the fan over that hole to blow air over the motor. This will aid cooling and make the motor compartm
ent air pressure higher than atmosphere and help keep dust out. Not sure it really needs a fan but better safe than sorry
Maybe cheesy idea but could you source an appropriate sized electrical mini panel housing box (or whatever they are called), trim it to desired stick-out width... similar to what you did on the VFD box? Might not be worth the cost/effort but from what I've see of home made boxes, its either sheet stock TIG'd together or homebrew vise bending brake... unless one has access to the typical equipment.
Attachments
Johnwa
Ultra Member
John
Thanks for the schematic. I should draw up mine. Effectively I have the top three lines of your drawing, Common, Reverse, and Forward. I do have a start and stop switch wired in but I’m going to have to trace it out as I can’t remember exactly how I did it. I made use of the original Start, Stop, and the F/R drum switch.
After yesterday I think a chuck cover and switch is a good idea! My Chinese VFD does have braking resistor connection which I will have to figure out. In the meantime I will duplicate your process for setting deceleration.
John
Thanks for the schematic. I should draw up mine. Effectively I have the top three lines of your drawing, Common, Reverse, and Forward. I do have a start and stop switch wired in but I’m going to have to trace it out as I can’t remember exactly how I did it. I made use of the original Start, Stop, and the F/R drum switch.
After yesterday I think a chuck cover and switch is a good idea! My Chinese VFD does have braking resistor connection which I will have to figure out. In the meantime I will duplicate your process for setting deceleration.
John
Peter, that is exactly what I have planned. Too much work to make a box when you can buy one for $15.
John, one more parameter I ran today seemed to smooth the motor performance is called auto tune.
John, one more parameter I ran today seemed to smooth the motor performance is called auto tune.
I just updated the schematic in post #50 to include the front panel mounted E-stop switch. When pushed it interupts the 24 volt control circuit to the main contactor. The contactor opens and removes 240 volt power from the VFD. That is the way I configured the wiring from the start, I just forgot to include it on the drawing.
Link to the Teco manual.
https://drive.google.com/file/d/1ljcx4BY24sPlFsrKKeJGsoO0Y4cBcNYX/view?usp=drivesdk
https://drive.google.com/file/d/1ljcx4BY24sPlFsrKKeJGsoO0Y4cBcNYX/view?usp=drivesdk
I've been reading information from Teco and Huanyang that says that high carrier frequency is hard on the IGBT's (large power transistors) in the VFD. Both companies warn that setting the frequncy to high will shorten the life of the IGBT's. With that in mind I decided try lowering the frequency setting I made ,16K HZ which is the maximum Teco allows. The reason to have it high is to eliminate the noise made by the transisitors. I lowered ot to 10K HZ and the sound is still almost inaudible so I'm going to leave it there. It is set with parameter 11-01
JohnW
(John)
Switching circuits are usually more efficient at lower frequencies. The goal is usually to try to get above 20KHz since most noise generated by that is inaudible to humans. For old people the limit is close to 12KHz. A young'in may complain about the high-pitched squeal from the VFD / wiring / motor coils when you don't hear it.The noise comes from the rapidly changing magnetic fields causing metal around them to vibrate.
Why? Because the IGBT's in the VFD (just like the FET's in most switching supplies) are run either fully on or fully off for minimum heat / maximum efficiency. When off there is no current flowing, so there is no heat. When fully on the devices will make very little heat. In the case of a MOSFET, the on resistance can be in the 0.01 to 0.001 ohm range. Using P=I^2R, the power dissipated is low, even if a few amps are flowing through it. With IGBT's the semiconductor junction will have a semi-fixed voltage drop somewhere in the 1-3V range. So with 10 amps flowing, it will dissipate 10-30 watts while turned on.
The current to the motor is varied by changing the ratio of on to off, not actually changing the voltage. The output frequency (5-100Hz for instance ) is generated by varying the motor current in a sine wave at 5-100Hz, by changing the on-off ratio at 20KHz.
The real problem is what happens as the switching devices (FET or IGBT) change from on to off. During that time period it is partially conducting, and just like a resistor it will dissipate lots of heat during the transition. Fortunately, the switching time is very short (IGBT's at well under a millionth of a second, FETs are somewhat faster). Why not use FET's since they seem to be better - it is because they are hard to make operate at 400+ volts, while IGBT's are easier to make for higher voltages.
The devices switch quickly, but if you are running the VFD at 20KHz, you are transitioning from on to off or off to on 40,000 times per second. 40,000 transitions at 0.5us per transition means the device is partially conducting (called linear mode) for 2 percent of the time. (20,000/1,000,000 = 0.02 = 2%). That means it is generating significant heat for 2% of the time. Reducing the switching frequency to 10KHz means it is only producing significant heat for 1% of the time, which is much easier on the device.
Why? Because the IGBT's in the VFD (just like the FET's in most switching supplies) are run either fully on or fully off for minimum heat / maximum efficiency. When off there is no current flowing, so there is no heat. When fully on the devices will make very little heat. In the case of a MOSFET, the on resistance can be in the 0.01 to 0.001 ohm range. Using P=I^2R, the power dissipated is low, even if a few amps are flowing through it. With IGBT's the semiconductor junction will have a semi-fixed voltage drop somewhere in the 1-3V range. So with 10 amps flowing, it will dissipate 10-30 watts while turned on.
The current to the motor is varied by changing the ratio of on to off, not actually changing the voltage. The output frequency (5-100Hz for instance ) is generated by varying the motor current in a sine wave at 5-100Hz, by changing the on-off ratio at 20KHz.
The real problem is what happens as the switching devices (FET or IGBT) change from on to off. During that time period it is partially conducting, and just like a resistor it will dissipate lots of heat during the transition. Fortunately, the switching time is very short (IGBT's at well under a millionth of a second, FETs are somewhat faster). Why not use FET's since they seem to be better - it is because they are hard to make operate at 400+ volts, while IGBT's are easier to make for higher voltages.
The devices switch quickly, but if you are running the VFD at 20KHz, you are transitioning from on to off or off to on 40,000 times per second. 40,000 transitions at 0.5us per transition means the device is partially conducting (called linear mode) for 2 percent of the time. (20,000/1,000,000 = 0.02 = 2%). That means it is generating significant heat for 2% of the time. Reducing the switching frequency to 10KHz means it is only producing significant heat for 1% of the time, which is much easier on the device.