Emcoturn 120 lathe retrofit
21 Jul 2016 11:48 - 21 Jul 2016 11:50 #77767
by LutzTD
Replied by LutzTD on topic Emcoturn 120 lathe retrofit
I removed the fwd/rev wires to concentrate on running. I set the VFD to accept 5v signal for speed and was able to start and run the VFD in the forward direction from linuxcnc. got the top speed working and all was good. Then I used parameters from the VFD vendor to get the braking working. First run it kinda shuddered below 10hz, then was smooth, took it to full speed about 105hz and then hit stop. it braked to a stop in about 2 seconds, pretty impressive, until I tried to start it up again. now it just flashes and clicks and wont start..... I sent the VFD vendor an email last night. lets see what happens but I am not optomistic
Last edit: 21 Jul 2016 11:50 by LutzTD.
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24 Jul 2016 00:07 - 24 Jul 2016 00:08 #77894
by LutzTD
Replied by LutzTD on topic Emcoturn 120 lathe retrofit
the seller asked me to take a video so they could see the issue themselves. I turned on the main breaker and set the vfd for 30HZ so I could get a video. hit the start button big loud POP and a cloud of white smoke. Unfortunately I did not have videos running. I emailed the results of their request back to them....
On another note, does anyone know of a VFD that will run a 5hp and has 1ph input. Seems like all the major makers want 3ph for 5hp.
On another note, does anyone know of a VFD that will run a 5hp and has 1ph input. Seems like all the major makers want 3ph for 5hp.
Last edit: 24 Jul 2016 00:08 by LutzTD.
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24 Jul 2016 00:17 - 24 Jul 2016 00:18 #77895
by Muzzer
Replied by Muzzer on topic Emcoturn 120 lathe retrofit
There are literally dozens. You might not want to buy from these boys but
here are some examples
.
It's arguably worth buying a good quality brand. I tend to favour Japanese myself for process controls or possibly even German.
It's arguably worth buying a good quality brand. I tend to favour Japanese myself for process controls or possibly even German.
Last edit: 24 Jul 2016 00:18 by Muzzer. Reason: Finger trouble
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24 Jul 2016 11:14 #77905
by andypugh
Replied by andypugh on topic Emcoturn 120 lathe retrofit
[quote="LutzTD" post=77894On another note, does anyone know of a VFD that will run a 5hp and has 1ph input. Seems like all the major makers want 3ph for 5hp.[/quote]
www.ebay.co.uk/itm/4KW-220V-VARIABLE-FRE...b:g:9QEAAOSwLVZVsPgr
(As an example)
There is some text in there saying that it is 380V, but I think that's a copy and paste error. It also says that the VFD can take 3 or 1 phase input.
Actually, most VFDs can run on single phase, the first stage of them all is just a rectifier, so unless the VFD had phase-loss detection they work OK on single phase. Ripple will be higher on the DC bus, and the rectifier diodes will be working slightly harder, but a lathe won't be running at full load very often or for very long.
www.ebay.co.uk/itm/4KW-220V-VARIABLE-FRE...b:g:9QEAAOSwLVZVsPgr
(As an example)
There is some text in there saying that it is 380V, but I think that's a copy and paste error. It also says that the VFD can take 3 or 1 phase input.
Actually, most VFDs can run on single phase, the first stage of them all is just a rectifier, so unless the VFD had phase-loss detection they work OK on single phase. Ripple will be higher on the DC bus, and the rectifier diodes will be working slightly harder, but a lathe won't be running at full load very often or for very long.
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24 Jul 2016 13:35 #77907
by jmelson
Replied by jmelson on topic Emcoturn 120 lathe retrofit
rectified 240 V comes out to 340 V DC with a capacitor-input filter.
One way to allow a VFD to run reliably from single-phase power is to use a VFD rated for a larger motor. For instance, for a 5 HP motor, get a 7.5 or 10 HP VFD. This insures extra capacity on the rectifiers and filter capacitors.
However, a VFD that blows up immediately on single phase power has something major wrong with it. The extra rectifier current and ripple will shorten the life of the rectifier and capacitors, but not such that it blows within seconds.
Jon
One way to allow a VFD to run reliably from single-phase power is to use a VFD rated for a larger motor. For instance, for a 5 HP motor, get a 7.5 or 10 HP VFD. This insures extra capacity on the rectifiers and filter capacitors.
However, a VFD that blows up immediately on single phase power has something major wrong with it. The extra rectifier current and ripple will shorten the life of the rectifier and capacitors, but not such that it blows within seconds.
Jon
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24 Jul 2016 14:05 #77908
by LutzTD
Replied by LutzTD on topic Emcoturn 120 lathe retrofit
looks like the one I bought is shown as "beware the cheap copy" in the link you gave...... Ill see if they will at least give something back....
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24 Jul 2016 14:08 #77909
by LutzTD
Replied by LutzTD on topic Emcoturn 120 lathe retrofit
I think what killed it was they had me set it for braking using the internal resistors to stop a 5hp motor and Xlb spindle going 4500RPM in 2 seconds. It stopped it, but it never worked again. The diagram on the advert showed connections for an external resistor, but there were no terminals on the unit I received, when I challenged them on this they said the internal resistors were enough
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24 Jul 2016 14:15 #77910
by andypugh
The internal resistors ought to be enough, and in the event of not being the VFD should fault-out with an overvolt and allow the spindle to coast to a halt.
That was an "ought" and a "should" that do not necessarily apply to some items on eBay.
Replied by andypugh on topic Emcoturn 120 lathe retrofit
The diagram on the advert showed connections for an external resistor, but there were no terminals on the unit I received, when I challenged them on this they said the internal resistors were enough
The internal resistors ought to be enough, and in the event of not being the VFD should fault-out with an overvolt and allow the spindle to coast to a halt.
That was an "ought" and a "should" that do not necessarily apply to some items on eBay.
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- tommylight
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25 Jul 2016 12:46 #77979
by tommylight
Replied by tommylight on topic Emcoturn 120 lathe retrofit
I have an Eurotherm drive that i paid over 800 euro several years ago, it is a single phase to 3 phase good for 240Hz.
I used it most of the time on a vertical mill with a 1.5KW motor with geared reduction, and it worked flawlessly.
I had cables made and connected with sockets so i can detach and attach to whatever i need it to, mostly for testing faulty motors, or running 3 phase motors on a single phase, as it is a time saver.
I did test a lot of things with it, including known broken motors, motors rated at 3KW ( VFD rated at 1.5 i think), pushed motors to way over their speed limit, and it never broke!! It will display what went wrong (over voltage, under voltage, over current etc), and move on. It has settings for active breaking and coasting and i did try to stop the mill within a single second, it did complain of over voltage and moved on.
Never had a single problem with it.
This is to confirm that Andy is right, it should not go up in smoke, even with a shorted motor windings ( i did test it, shows over current ).
It is a small little bugger, but tough to the extremes.
Regards,
Tom
I used it most of the time on a vertical mill with a 1.5KW motor with geared reduction, and it worked flawlessly.
I had cables made and connected with sockets so i can detach and attach to whatever i need it to, mostly for testing faulty motors, or running 3 phase motors on a single phase, as it is a time saver.
I did test a lot of things with it, including known broken motors, motors rated at 3KW ( VFD rated at 1.5 i think), pushed motors to way over their speed limit, and it never broke!! It will display what went wrong (over voltage, under voltage, over current etc), and move on. It has settings for active breaking and coasting and i did try to stop the mill within a single second, it did complain of over voltage and moved on.
Never had a single problem with it.
This is to confirm that Andy is right, it should not go up in smoke, even with a shorted motor windings ( i did test it, shows over current ).
It is a small little bugger, but tough to the extremes.
Regards,
Tom
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25 Jul 2016 13:10 #77983
by Todd Zuercher
Replied by Todd Zuercher on topic Emcoturn 120 lathe retrofit
Any decent VFD should have protections built in. (Calling a super cheap Chinese drive decent may be a stretch.)
I've only ever had 3 VFDs fail, all 3 were quite old with a lot of hours. One I was able to repair with a simple rectifier replacement. and I think all were killed by power surges from the power grid. I've never had a motor failure or wiring problem (including phase to phase direct shorts) kill a drive, they always have just faulted out and shut down.
I've often ran larger motors on smaller drives. Running a 7hp motor, with a 5hp drive will run perfectly well, you just don't get 7hp out of it.
I've only ever had 3 VFDs fail, all 3 were quite old with a lot of hours. One I was able to repair with a simple rectifier replacement. and I think all were killed by power surges from the power grid. I've never had a motor failure or wiring problem (including phase to phase direct shorts) kill a drive, they always have just faulted out and shut down.
I've often ran larger motors on smaller drives. Running a 7hp motor, with a 5hp drive will run perfectly well, you just don't get 7hp out of it.
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