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Member postings for Rockingdodge

Here is a list of all the postings Rockingdodge has made in our forums. Click on a thread name to jump to the thread.

Thread: Lathe/VFD/DRO issue
22/06/2023 15:15:20

Roger,

Don't discount it, it's a positive change, look at the scale cable routing, are they the same?

If you swap the scale cables over does the fault move display port as well? If it does take the d-type plug covers off making sure you don't loose the screws and see if the earths are both terminated the same. If they are try a temp earth to the scale read head.

If it stays the same port the display is likely duff inside and you may have to shield the VFD, as in, wooden box, glue some earthed kitchen foil inside , bodge etc. Or buy decent cable and move it further away till it's out of range.

Thanks Dave,

Some positive steps to try, just watched a Clough42 utube as he had similar issues albeit affecting his cams and monitors so I think my initial steps should be to purchase some 3 core and earth cable (what size cores for 2,2kw? plus a filter for the mains input, again what one should I get?

Roger

22/06/2023 14:24:05
Posted by JasonB on 22/06/2023 14:18:00:

Roger, you said you had connected the Screen (assumed DRO screen/panel) to the other two earth wires(assume earths in VFD)

What Robert has suggested is earthing the metal sleeve around the cable from VFD to motor as you don't have a metal box for a metal gland to connect two he has suggested using a metal plate that all other earths can be connected to. If this is what you meant by screen then do similar to the DRO sleeves and also check the VFD instructions to see if they say one end or both connected to earth

He also suggested an EMF filter as your VFD may not include one. Does it?

When I said screened cable I meant the cable from the vfd to the motor which I may have mistakenly thought the wire wrapping was the scrrened part of the cable, think it was a case of me thinking one thing and you understanding another. I would never directly connect the dro panel earth into the vfd earth, that would be a no no.

Roger

22/06/2023 13:53:46
Posted by John Doe 2 on 22/06/2023 12:00:00:
Posted by Rockingdodge on 22/06/2023

Putting the vfd into a metal box would mean I would not have access to the controls so what next guys?

Roger

Robert was trying to explain that to you, and has explained similar questions on other VFD threads. But you told him to "butt out".

Very rude.

Edited By John Doe 2 on 22/06/2023 12:01:28

No not rude just fed up of members talking over my head about what I should have bought and how I should reach industrial standards in a little one man hobby shop.

What I need, reall really need, is someone to walk me through in baby steps what to try in order to succeed in eliminating the interference, that's all I asked for and all I need.

Jason

I've tried Roberts suggestion as indicated in the post before your reply.

Dave Halford

Good point, I'd assumed the cable was screened as it was 4 core cable for 3 phase and that the wire wrapping was the screening, bought way back before the DRO installation.

I tried earthing the dro panel and initially seemed to work with one of the dros but not the other so I'll discount that as a coincidence.

so what do I try next? replacement cable first?

Roger

22/06/2023 11:14:26

Keith, Emgee yeslaugh

Robert, NDIY, I assume that you have purchased these vfds from Vevor or had one in your hands in order that you can make a considered opinion as to their quality and fit for purpose'

I stated in an earlier post that 'I have no doubt after following some of the previous discussions in the forums I will be slammed by some for not following current regs whatever they are now but really hope they restrain themselves and focus on the easiest methods for me to get my DROs reading correctly'

This still applies so either help me find a fix or just butt out, I have no time, patience or money to throw away what has worked perfectly without the DROs when I'm getting old enough not to worry if I'm going to wake up in the morning and find I'm now dead!!!

Rant now over. Now considered help please not wrong choices etc.

OK now I've 'temporary tied in the screen to the 2 earths and has not made any difference.

Putting the vfd into a metal box would mean I would not have access to the controls so what next guys?

Roger

21/06/2023 22:00:41
Posted by An Other on 21/06/2023 21:55:14:

Rodger, If all seems OK with the motor not running, then its likely the problem lies with the connection from the VFD to the motor, or the VFD/container grounding. If the motor is not running, then the VFD is not producing the "modified" drive sinewave outputs (actually composed of square waves). The edges of these square waves are usually what produces the interfering harmonics, so if the motor is not running, then any interference is much reduced.

Make sure the earth(s) you mentioned are made, then check that the motor cable (which appears to be screened in your photos), is firmly connected, and that one or both ends of this screen are also grounded. If that doesn't have any effect, then I would try re-routing the motor cable. These are the simple possibilities, and must be eliminated before moving on to more laborious checks, otherwise you could do a lot of work for nothing.

Thanks Keith, I will do this in baby steps, I know very well from debugging code both in my ex-working life and hobby work that the worse thing to do is make multiple changes, always bites you where it hurts.

Roger

Edited By Rockingdodge on 21/06/2023 22:02:35

21/06/2023 20:47:01
Posted by Richard Millington on 21/06/2023 20:38:03:

Do the DRO reader head cables run parallel to the motor cable from the vfd?

If you disconnect each DRO reader head in turn does it still happen?

Where is the DRO display situated in relation to the VFD and motor?

The motor cable is running in the opposite direction to where the DRO cables are.

I'll try that when I'm in the workshop tomorrow.

The display is approx 18" (1650mm) away but at the same height.

21/06/2023 18:50:28
Posted by Emgee on 21/06/2023 18:32:04:

Hi Roger

Some makers suggest connecting the screen to earth at both vfd and the motor, others say only at the vfd so check what your maker suggests.

Get ready for those who will tell you the cables should be terminated in a gland plate, no doubt a good idea but not related to your interference problem.

 

Emgee

I have to admit I've not tied in the screen to earth and will do so, I have no doubt after following some of the previous discussions in the forums I will be slammed by some for not following current regs whatever they are now but really hope they restrain themselves and focus on the easiest methods for me to get my DROs reading correctly devilsmiley

Roger

Edited By Rockingdodge on 21/06/2023 18:53:41

21/06/2023 17:59:06

The vfd & DROs were purchased from Vevor UK so I 'assume as they are from a UK warehouse' that they are CE marked (legally)

The lathe is a 1937 Denham Junior MkII so not fitted from new, other info requested can be seen in my previous post.

Roger

21/06/2023 17:48:03

OK, both have screened cables and the dro works normally with the vfd switched off, also with it on but motor not running.

vfd connections are as below:-

img_20230621_165629.jpg

img_20230621_165638.jpg

and the motor is earther inside the box

img_20230621_165843.jpg

DRO screened cables:_

img_20230621_165656.jpg

These are both plugged into the ring main in the workshop.

I have a mill with the same make DROs but single phase motor and don not have the same issues.

I don't know if it is earthing issues or interference from the motor but it's not my skill set so would appreciate any help with this.

Thanks

Roger

21/06/2023 14:47:33

I have an issue in that when I start my lathe the readouts start incrementing without me doing any machining. Could it be an earth issue? I know all my wiring is correctfor the lathe to run with the vfd.

Roger

Thread: Newbie with a denham junior mk 2
21/05/2023 10:10:40

Chris, check your ibox for a message re manual

Regards

Roger

Thread: Medding
25/04/2023 11:55:32

I have the same switch on mine, you could contact Meddings as they do have some 'old' spares but they're not cheap!

Thread: Useing Citric acid
14/04/2023 22:45:28

Thanks, I can get plenty of it as my son works in the food industry but I don't want to 'overcook it', it's what I tend to do devil

Thread: Warco WM18 Y Axis power feed project
14/04/2023 14:57:34

Y axis? surely you mean the X axis which is the right and left travel?

Thread: Useing Citric acid
14/04/2023 11:04:47
Posted by Nealeb on 14/04/2023 10:09:55:

I use a citric acid-based pickle in my ultrasonic bath - the combination of warmth and vibration cleans up after silver soldering very effectively. I have two bottles of solution made up. One for steel and one for copper/brass.

What strength do you use for each solution Neal?

Thread: What did you do today? 2023
27/03/2023 10:37:44
Posted by Oldiron on 27/03/2023 10:32:22:
Posted by DiogenesII on 27/03/2023 07:42:25:

..feared for my Tomentosum..

img_2121.jpg

Could be Sunday roast. devil

regards

Oh deer! devildevil

I'm going now laugh

Thread: Bore mic/comparitor?
09/03/2023 10:24:16

Nice one John, a few more probes than mine.

06/03/2023 11:43:12

Some more photos as promised:-

groove comparitor.jpg

verdict dial gauge.jpg

As it's a verdict gauge would it be safe to assume that it's a verdict groove comparitor?

accessories.jpg

Full set of accessories plus a couple of odd ones. What would the extra clamp on the right of the pic be for?

Roger

05/03/2023 20:36:07

I'll take some more photos tomorrow, hopefully they might clarify the action.

Roger

05/03/2023 17:03:10

Just bought this but no name or company on the tool or box, seems quite old. Anyone able to identify it and it's purpose?

bore mic.jpg

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