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19th May 2015, 12:42 PM #1Golden Member
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Huanyang VFD issue when engaging lathe clutch
I am having a problem where when my lathe motor is running at 1430rpm, using the clutch to engage reverse causes my 4kw Huanyang VFD to trip its over-current at constant speed breaker (E.OC.n). The motor is a 2.2kw high efficiency W21 WEG (8amp rating).
I set the max motor current in the VFD (PD142) to 8 amps. Could it be that my motor requires more amps when I engage the clutch at high speed? Should I increase this figure from 8amps to 10/12/14/16? Will this likely damage the motor?
The clutch engagement works fine at slower speeds.
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19th May 2015, 04:21 PM #2Member: Blue and white apron brigade
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Definitely sounds like a current limit of some sort so upping the max current might fix it.
Are you able to apply the clutch in a slower manner? It could be the change in load is too much for it
I'd be increasing the current limit a couple of amps at a time and testing it but probably wouldn't go more than 12A on a 2.2kw motor.
This is where a ammeter on the VFD input side may help work out what is going on.
Why aren't you using the VFD reverse?
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19th May 2015, 05:09 PM #3Golden Member
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Thanks for the help BobL. I wanted to be sure that the motor could handle more than 8amps before proceeding. I will increase the amps and see how things go.
The clutch cannot be applied slowly as it's electromagnetic. As soon as the volts flow the thing jumps into action. It does not appear to have any type of half-way point.
The VFD is being used for reversing the motor which is triggered by the motor speed & direction drum switch. The motor connects to the clutch which then controls the spindle direction and brake. The reverse has a 1:4 ratio.
I have been watching the current on the VFD screen. Running at high speed it sits slightly under 4amps with no load. Slow speed it draws 1.7amps. I have a clamp meter (ammeter) that I can use to confirm if increasing the amps does not help. As it stands at the moment I have no idea what current it draws when it trips out (merely a suspicion) as it trips before the LCD can update the amps figure (the clamp meter will be of more use).
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19th May 2015, 05:24 PM #4Golden Member
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What type of Lathe are we talking about here? Is this the original motor? If not, what size was the original motor?
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19th May 2015, 05:37 PM #5Golden Member
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German made Boley 5LZ. Original motor was 2 speed 1.8kw - 725/1450rpm. I swapped it out for a 2.2kw WEG single speed 1435rpm. VFD is a 4kw unit.
The motor has no problem running high speed and flicking into Forward. The issue is isolated to the 1:4 Reverse (at high speed only).
I will mention that I have not cut any metal with it however. The whole thing could stall when cutting, in which case it will be back to the drawing board.
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19th May 2015, 06:55 PM #6Cba
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Beautiful machine, but a very complex drive system... 2 clutches... speed changes on the fly.... electrically operated 1:4 gearbox... increased speeds in reverse..... http://www.lathes.co.uk/boley5lz/
I am not sure about this. But I fear that you may have to make a choice here. Keep the drive train original, or up-grade to a VFD (or shall we beter say, side-grade to a VFD). These clutches and a VFD are possibly not an optimal combination. You may at the end find a set of VFD parameter settings that work with this very particular drive, but I doubt its ever going to be ideal. You would probably have to stop the motor before switching speeds. Just out of curiosity, what were your reasons to go for a VFD?
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19th May 2015, 07:42 PM #7Golden Member
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[QUOTE=cba_melbourne;1866593]... increased speeds in reverse..... http://www.lathes.co.uk/boley5lz/
That's what I suspected and the reason why it is harder to start in reverse.
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19th May 2015, 07:46 PM #8Most Valued Member
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Just one question about the original motor, was it much larger then the replacement?
Stuart
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19th May 2015, 08:07 PM #9Member: Blue and white apron brigade
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I see.
[Minor point - Volts are "applied" , and if anything it's current that "flows" ]
The VFD is being used for reversing the motor which is triggered by the motor speed & direction drum switch. The motor connects to the clutch which then controls the spindle direction and brake. The reverse has a 1:4 ratio.
Is there some kind of automated gear changing mechanism involved when the motor runs is reverse?
If not I would look at locking the clutch and just using the VFD for the FWD and reverse.
If yes then there may be a way of disconnecting the mechanism?
I have been watching the current on the VFD screen. Running at high speed it sits slightly under 4amps with no load. Slow speed it draws 1.7amps. I have a clamp meter (ammeter) that I can use to confirm if increasing the amps does not help. As it stands at the moment I have no idea what current it draws when it trips out (merely a suspicion) as it trips before the LCD can update the amps figure (the clamp meter will be of more use).
The other thing to look at are motor acceleration and deceleration times.
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19th May 2015, 09:56 PM #10Golden Member
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Thanks Chris for the explanation of the 5LZ. For those interested another 5LZ owner (Teun) graciously uploaded a video of his 5LZ running at my request. You can see it here: https://www.youtube.com/watch?v=Adeb6YiJnfY
The reason for the VFD, is that I purchased a 5hp Rotary Phase Converter (Phase Changer brand) but it was bogging (running at max load) when I switched to high speed. I decided that rather than going any further I would try a VFD and new motor. Not the way I wanted to do things, but I was getting nowhere with the RPC. I thought the VFD would see me up and running without butchering any of the original gear.
I have seen you ask this question before.. The origional is not much bigger than the replacement in terms of physical size. Maybe 10-15% larger. But that could be the big cast iron casing vs the aluminum of the WEG..
For the record the WEG was not all beer and skittles. I had to disassemble and turn down the shaft and re-cut the keyway to suit the Boley fixings.
IMG_0156.jpg IMG_0167.jpg IMG_0175.jpg IMG_0199.jpg
Tiredness getting the better of me..
I am not an expert on it. I know the clutch has a bunch of gears inside which possibly constitute an automated gear change? I reluctantly diassembled over the weekend to check for any obvious damage. Nothing jumped out at my untrained eye.. No burns, no scoring..
IMG_0305.jpg IMG_0335.jpg
I tweaked the acceleration times. I pushed it out to 200 without any impact.
I am going to rewire the VFD to motor and power point. It is probably getting amp-drop because of the light leads I have used in testing. I will run some serious heavy gauge and see if that makes any difference.
Incidentally upping the amps on the VFD above 8 amps results in an "E.OC.A" error. No idea what the "A" stands for? But it looks like the VFD is not agreeing with increasing the amps..
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19th May 2015, 10:28 PM #11Cba
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Ask yourself how you personally like to work with the machine, what are its features that you value particularly.
You can keep the machine original, but need a larger phase converter.
Or you can make the switch to VFD variable speed. Keep the flat belt and the 3 position belt change, you need its mechanical advantage. Get rid of that automatic 1:4 gearbox stuff and the clutch thing. You can possibly keep the brake feature.
Either solution will work well and make you happy. Whereas keeping the drive original AND adding the VFD may create something of an unreliable bastard monster.
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19th May 2015, 10:59 PM #12Most Valued Member
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Hi Bob,I believe its for all singing all dancing automatic(or at least semi automatic) threading with 4 times reverse speed with not need to open half nuts. (I do wonder just how high a speed it was meant to be used??)For a different reason this time. I was wondering if you'd removed much inertia from the "spinny bits" that aren't reversing.Can you start the lathe in reverse(with the lever not REV on the VSD) and change to FWD without it tripping?A=At accelAt a guess you're going to have to max the VSD amps(once you've sorted out the input wiring). While this may then allow your lathe to work, it will remove the VSD protection of the motor over current........Even at 4kw x 150% is only 6kW which might not be enough.Do you know much about the brake/reverse timing?(its adjustable isnt it?)Stuart
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20th May 2015, 09:00 AM #13Most Valued Member
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with the overload setting....is there a time setting that can be set to allow increased over current draw of motor before VSD actually sees it and subsequently trips?
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20th May 2015, 11:20 AM #14Cba
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Just as a try. Have a play with PD032 and PD033. This is about frequency track time. After a disturbance (like a quick drop in motor rpm caused by your clutches overloading temporarily the motor) the VFD tries to catch again the frequency of the motor. If this track time is set to short, the VFD cannot synchronize with the motor and a full stop will be necessary for a restart. I think it is a similar feature that other VFD makers use for "catching" on the fly an already spinning or coasting motor, for example after a power failure.
I assume you have a Huangyang manual? They are not particularly well written. This what I found online, but your model may be different: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&cad=rja&uact=8&ved=0CDMQFjAE&url=http%3A%2F%2Fwww.c-n-c.cz%2Fdownload%2Ffile.php%3Fid%3D42252&ei=b9JbVdOfGYqvyQTMkID4Dw&usg=AFQjCNHTQcxs-KhJkvkhMdxVFPzkoYJtsA&bvm=bv.93756505,d.aWw
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20th May 2015, 03:31 PM #15Most Valued Member
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could it be PD119, PD120 thru to PD125 or others in that vicinity of the manual?
have'nt read all the manual or played with one of these things yet...((but I will get my chance soon on a $180k, 27000rpm VFD centrifugal chiller (oil less system....has magnetic bearings) I am putting in and due to be commissioned august...))
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