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Author Topic: Huanyang VFD problems?  (Read 5109 times)

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Offline Jacko

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Huanyang VFD problems?
« on: January 27, 2017, 01:21:38 PM »
Can any one help with this please. I have had the VFD, which drives a 1.5kw spindle , for a year or so but when I start the spindle up now all the stepper motors start "twitching" and they can  move the spindle quite a long way. This even happens without mach being  loaded.  I assume the VFD is faulty unless there is something I'm missing. Anyone experienced this? Any suggestions?
Thanks
Jacko
Re: Huanyang VFD problems?
« Reply #1 on: January 27, 2017, 02:45:10 PM »
Hi,
the VFD is generating noise which is affecting your stepper drivers. Has anything changed, wires re-routed, new spindle motor, anything?

Usually if a VFD goes faulty it blows up often quite spectacularly. The fact that it still works suggests to me that the fault is elsewhere. Do you
or an electrician friend have a Megger? I would be disconnecting the spindle and insulation testing the spindle. VFD driven motors are subject
to insulation damage which makes them potentially dangerous as well as plain faulty.

The most likely transmission of noise from the VFD/motor is conducted noise in either input or output circuits. Trick here is to make some
reasonable tests to localise the problem.

One suggestion along these lines is to make a balanced 3 phase load to temporarily replace the spindle. I would suggest 3 large say 500w light
bulbs or spotlights hooked up in delta configuration. If you fit such a load and the noise problem disappears or is significantly reduced then
a line reactor solution is the way to go. The manufacturers manual should give you a starting point.

The other main and highly probable noise path is at the input of the VFD. Can you separate the input supplies from the VFD and the stepper drives?
A line input filter is highly recommended for VFDs no matter wether noisy or not. Small/cheap line filters WONT do, you need something with probably
20A rated or more, and plenty of surge overhead, 40A or better.

In New Zealand at the current time ther has been a major upsurge in the use of VFDs for irrigation pumps. They commonly top 150kW. They play merry
hell with the electricity supply in rural locations to the extent that the power authorities are insisting that farmers fit noise suppressing equipment
both line reactors and input filters. They often cost as much as the VFD itself and the farmers are whinging big time!

I make this point because noise suppression in VFDs is NOT trivial. Just because the VFDs we use are baby ones does not mean that they can be treated
lightly. Make sure that whatever you use complies with the manufacturers specs or at the very least is industry rated for the purpose otherwise
you will ensure that your VFD is faulty....for good!

Craig
My wife left with my best friend...
     and I miss him!

Offline Jacko

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Re: Huanyang VFD problems?
« Reply #2 on: January 27, 2017, 03:58:14 PM »
Hi Craig,
            Thanks for the reply. I haven't made any changes to the machine. I now  remember that I have had the problem for a while as this has happened before, albeit to a lessor degree. I managed to get away with it by plugging in the VFD in a plug socket, on its own,  a fair distance away. This seemed to cure the problem but I have noticed recently that the machine was sometimes not repeating a tool path. Now I think that there may have been an occasional "twitch" whilst working that I hadn't noticed causing the machine to "jump" This problem just seems to have gradually got worse. I did notice that it was far worse when building up to speed.  When it reached the required speed it hardly "twitched" I might just try plugging it into a completely different circuit in the morning to see if that has any effect.  I also think that I need an electrician!! You wouldn't just like to "pop" in tomorrow would you?
Many thanks
Jacko
Re: Huanyang VFD problems?
« Reply #3 on: January 27, 2017, 05:26:24 PM »
Hi Jacko,
you provide the air tickets and I'll be there!

From your description you are looking at input noise probably being conducted thru supply wiring to other more sensitive components.
Input filtering is the answer. I'll do a bit more reading and some market research and may be able to come up with a device which will
help.

For safeties sake you should get your spindle insulation tested. Can you take it off and take it to any electrical repair shop? A five minute excerise
to test it out.

Craig
My wife left with my best friend...
     and I miss him!
Re: Huanyang VFD problems?
« Reply #4 on: January 27, 2017, 07:14:39 PM »
Hi,
line filters $10-$40 don't do a bad job for EMI but the real deal is something like this:
http://www.ebay.com/itm/FRAKO-TR98230-Single-Phase-Reactor-208V-60Hz-22-7A-/331859248184?hash=item4d445a4438:g:WjYAAOSwn9lXKRaC

Craig
My wife left with my best friend...
     and I miss him!

Offline Jacko

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Re: Huanyang VFD problems?
« Reply #5 on: January 28, 2017, 10:00:19 AM »
Hi Craig,
             I run a homemade cnc lathe off the same control box and so I have to swap all the leads and plugs about when I run that and plug them in to all sorts of extension leads etc. This problem occurred after I had just used the lathe and had plugged every thing back in to use the router.  This morning I took all the plugs out and made doubly sure that the VFD was definitely plugged into a totally different socket.  Hey presto, it has been working fine for 30 minutes.  As you rightly say, some sort of interference issue but I am just grateful that at least the VFD & motor appear not to be damaged.  Hopefully it will continue to run ok
Many thanks for your time and advice.
Jacko
Re: Huanyang VFD problems?
« Reply #6 on: January 28, 2017, 06:32:38 PM »
Jacko;
Been there done that.  I have a HuanYang VFD drive as do you.  This isn't meant to imply these generate more or less electrical noise than any other drive - I don't know.

Three things I did as I built my CNC machine to stop the VFD's electrical noise from interfering with the electronics:
1) Made absolutely sure I did NOT daisy-chain electrical grounds.
2) Put VFD in it's own metal electrical enclosure.
3) Made sure cable from VFD to spindle was as far away as possible from other electrical cables (limit switch wiring, etc.)

I still suspected I had an occasional issue caused by electrical noise, so I placed noise suppression toroids
* On the power leads AT the VFD,
* On the power leads going to the spindle AT the VFD,
* and on the power leads going to a Programmable Logic Controller (AT the PLC) I use on my machine.

Because you will never know if you fixed the problem until it never returns (which hopefully is a long time), I think this is one of those situations where it isn't worth it to figure out EXACTLY what is causing the problem... it is easiest to address all the things that MIGHT be causing the problem and move on.  OK, my logic here might be suspect (smile).

My toroids measure 18mm OD, 9mm ID, and 5mm thick.
Sorry, I don't have the specs, but the look a lot like http://www.ebay.com/itm/7mm-Inner-Diameter-Ferrite-Ring-Iron-Toroid-Cores-Yellow-White-50PCS-LW-/181834403242?hash=item2a562ccdaa:g:iEYAAOSw4UtWTwGZ:

Not endorsing this seller, or the product, just that this is what mine LOOK like.
There are scholarly articles on what size, type, etc. to use.

Best of luck.

Offline Jacko

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Re: Huanyang VFD problems?
« Reply #7 on: January 29, 2017, 03:18:23 AM »
Hi,
    Thanks very much for the interest in my issues and your comments.
What a fantastic medium this forum is when some one in the UK can have a problem with their hobby and people from all round the world can chip in, offer support, and share their experience. What a small world.
Many thanks to all.