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  #1  
Old Wed 12 October 2011, 15:03
IN-WondeR
Just call me: Kim
 
Randers
Denmark
VFD NOISE, please help...

I have some noise coming from my VFD, and I can't get it to go away.

I have tried just about anything soon, only adding a Filter or Line Reactor is missing. I don't have a line reactor for 230V laying around.
I have the whole machine Grounded, and it works just fine, it almost removed all the noise, so all I need now is the last bit of noise.
I tried a ferrite on the power side of the VFD, no luck in removing the last bit of noise with that. Is there any other ideas out there?

Also, is there someone who can show me the correct way of finishing the wires at both ends on both the VFD but also the spindle, I might not have done it good enough.

I hope someone can help, even though it's not a Mechmate I'm working on.
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  #2  
Old Wed 12 October 2011, 19:48
PEU
Just call me: Pablo
 
Buenos Aires
Argentina
noise as 1) this high pitch noise is killing my ears or noise as 2) the vfd makes your limit switches go berserk?

if option 1) check the carrier frequency of your VFD, there is a sweet spot, its usually around 10khz but varies from vfd to vfd, this is called electromagnetic noise

if 2) Check grounding, usually ground loops or poor shielding, always put to ground one side of the shield.

Or maybe you refer to none of these
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  #3  
Old Thu 13 October 2011, 00:35
IN-WondeR
Just call me: Kim
 
Randers
Denmark
Ahhh, offcourse, I need to specify the noise..

When I start a Program (Gcode) without the spindle active, then there's no problem, but just as the spindle is turned on, then my motors start acting up, losing steps and chatter emerges.
But when I run without the spindle then theres no problem what so ever. So I believe that it's only the spindle doing the noise, or the VFD.
Everything is grounded, so no problems at that point (I believe). Only thing I can think of should be that I might not have done the cabling to my HuanYang VFD good enough, or that it might be giving of some more noise than I would have thought so.
All my drivers PSU's and VFD are mounted in the same cabinet, I have seen several builds in here where this is done, and they seem not to have any problems. So there must be something I have done wrong since it's not working for me.
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  #4  
Old Thu 13 October 2011, 01:32
danilom
Just call me: Danilo #64
 
Novi Sad
Serbia
What make is the VFD?
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  #5  
Old Thu 13 October 2011, 01:36
IN-WondeR
Just call me: Kim
 
Randers
Denmark
It's the Chinese HuangYang VFD 2.2kW
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  #6  
Old Thu 13 October 2011, 02:03
danilom
Just call me: Danilo #64
 
Novi Sad
Serbia
Grounding terminal E. Be sure to make correct grounding
220V class: The third grounding method (Grounding resistance should be 100Ω or lower.)
380V class: The special third grounding method (Grounding resistance should be 10Ω or
lower.)

look trough the manual if you haven't
http://www.cnczone.ru/forums/index.p...e=post&id=4180
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  #7  
Old Thu 13 October 2011, 02:37
IN-WondeR
Just call me: Kim
 
Randers
Denmark
Well, the VFD is correctly grounded then. I tried another scenario, I took the Computer power from a different socket in the shop instead of from the Machine Cabinet power, and then the problem dissapeared. I believed that it was because there's no ground on this, but no, as soon as I found a wire for the computer with ground lead in it, the problem came back even bigger than before. I really don't hope I need to do a complete rewire of my entire machine... Maybe I should take the VFD out of the cabinet and make a new cabinet for that only, I don't know if it would do any good, but I'm fresh out of ideas now...
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  #8  
Old Thu 13 October 2011, 03:36
IN-WondeR
Just call me: Kim
 
Randers
Denmark
Well, the computer power was the problem. I have mounted all my 230V power to the same relay, including the power for the VFD and Computer, different phases though, as I'm running 400V 3 phase into the machine mains power. But the interferrence from the VFD seems to mess up my computer, so it can't send out steps, and then looses them. I have now tried to move the power inlet for the computer to the mains plug in the shop where I draw mains power to the machine also, then there is no problems what so ever. I'm a little puzzled about it, but I guess I might have to do a complete rewire of my entire box to get it to fit in another way. I would still love to be able to put the mains for my computer into the electronics cabinet, but I'm affraid that it will not be possible to do so because of the interferrence from the VFD.
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  #9  
Old Thu 13 October 2011, 04:07
danilom
Just call me: Danilo #64
 
Novi Sad
Serbia
The VFD produces interference that is sent out trough power lines, and messes up the step/dir signals, I dont't think it can mess up the CPU or the chipset as it would not function at all. So only filters and shielding is going to help, changing the power socket might help as there might be better ground or something else. Remember step/dir rely on proper GND so it serves as reference for estimating is the signal 0 or 1 (0 or 5V). And you draw it from the computer GND which is originating from the PSU.

VFD problems are always not easily explainable because of their nature

I've seen problems with CNC machines input ports, where not grounded PC has been connected and destroyed the input card, so recommendation is to use a laptop which runs of a DC power, and it never happens again. Just something from the daily practice of a friend.
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  #10  
Old Thu 13 October 2011, 06:12
KenC
Just call me: Ken
 
Klang
Malaysia
I have the PC vs VFD situation too. I even have my monitor flicker constantly!
What I didi:-
Use over a dozens of ferrite beats everywhere &
RFI/EMI filter for the PC input & RFI input line &
Separate power line phase for the PC, VFD & MM control panel
VFD mount on the open wall,
control panel mounted under MM table &
PC on a disused computer desk.

Thing seems to be working since.

while I was at it, I made a 4.5m long shielded printer cable from double-shielded Cat5e cable.

I recon RFI is still heavy in the shop as my radio will pick up noise very loud noise when the VFD is turned on.

One note on the PC on a computer desk. I get plenty of flat horizontal surface to pile up junk... such as the bits, tape, tool box, nails, hammer...etc etc etc

Last edited by KenC; Thu 13 October 2011 at 06:15..
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  #11  
Old Thu 13 October 2011, 09:21
IN-WondeR
Just call me: Kim
 
Randers
Denmark
Hi Ken...

I have tried alot, and so far it seems like just moving the connection for power to my PC outside the cabinet, but still on the same mains works for me. No more noise, and nor more problems. I'm hoping it will keep working this way...
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  #12  
Old Fri 14 October 2011, 00:02
KenC
Just call me: Ken
 
Klang
Malaysia
Lucky you
I know nuts about EMI & RFI, so I navigate from all these problem by taking all good practices base on basic EMI & RFI behaviours.
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  #13  
Old Fri 14 October 2011, 00:48
IN-WondeR
Just call me: Kim
 
Randers
Denmark
Yeah I'm just lucky.

I know nothing about this either, so I'm just doing trial and error problem solving.. This time I got lucky, but maybe not next time. Sometime in the future I migt be making a brand new Electronics Cabinet with way more space than there is in my cabinet right now. Then I might see if I can find someone to help me with all the different problems that might rise through all of this.
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  #14  
Old Mon 17 October 2011, 19:28
Besser
Just call me: Besser
 
Vic
Australia
My 2c:
Run dual Earth system including 2 ground rods. make one for the dirty power the other for data. Sink these as far apart as possible.

The ground conducts and has it's own electrical tracks - just ask lightning!
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  #15  
Old Thu 01 December 2011, 21:31
digger
Just call me: Milosh #113
 
Toronto
Canada
Good reading regarding Radio Frequency Interference:

http://www.audiosystemsgroup.com/RFI-Ham.pdf
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