Unknown Swiss milling machine

Too late to edit my last post ... Here is the big ABB controller:

**LINK**

http://www.quantum-controls.co.uk/products/abb-variable-speed-drives/acs800-01-0120-5.html

MichaelG.

That is exactly the type of cable I suggested and what many use.

Your inverter manual should spec the cable size.. The 1.5mm is the cable area and you may find that you have to use a larger size than the manual suggests.

The feed to the inverter is usually filtered internally but nor always.

JS - Don't you think that I have already done that ? Probably not it seems. They can be made as quiet as an ordinary motor set up but it's an expensive option. Not doubt I have the nosiest inverter on the market.

John

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Michael - CY has copper (usually tinned) braiding in place of the steel braiding of SY. No it isn't as 'strong' but it does conduct RF frequencies to ground more effectively. For avoiding RFI/EMC issues it is a better bet. You'll have to decide what balance is necessary in your application between mechanical robustness and EMC performance.

.

Thanks, David

I think I'm happy to go on the advice of the ABB Drives & Motors 'Supplier of the Year'

**LINK**

http://www.quantum-controls.co.uk/about-us/about-us.html

Incidentally; I only posted the 'Eland Cables' link because it includes a good diagram of the preferred 'symmetrical' construction.

MichaelG.

There is some info about from Mitsubishi on emissions Michael. Length is probably more important than anything else. It's best to keep the motor power lead short and no longer than needed. They give info on lengths of 20m and up in some of their data sheets. The carrier frequency can also have an effect.

It's possible to connect to the shielding which ever type it is via P clips. Just metal bent into the shape of a P with 2 thickness's on the upright part with a hole through them for fixing. How they can be used depends on what is being connected. Your inverter may have a plate for this used to locate the cables. I did look quickly at your manual but the clips are likely to be easier than unpicking and twisting and then fixing them in an eyelet some how.

By using the armoured cable you also have an earth lead. That will also help.

Not sure if I saw a note about keeping the control leads at least 10cm from the power leads.

Rather long power leads to the inverter can also cause problems. The mains filters for solving that aspect are pretty cheap if needed but can cause problems with rcd's.

John

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Edited By Ajohnw on 17/08/2016 19:50:42

Thanks, John,

I will have a look for the Mitsubishi information, out of interest.

I should however mention that both motors for this machine will need to be on flex as opposed to cable.

• The Aciera head is interchangeable with the pantograph mechanism and might best be considered as a 'portable tool'.
• The motor for the pantograph is in the base of the machine, but is on a swinging-arm mounting for belt tensioning; so it too needs to be powered via flex.

That's why the supplier advised the use of SY flex.

MichaelG.

Michael,

I think you might find this publication by Beldon interesting (I have you down as researching carefully before jumping! ) **LINK**

Also of interest is the small wiring diagram at the top of page 2 showing the earth screen connected both ends - the way I understood it was meant to be done rather than the conventional single ended arrangement for screens, this is the way all my personal and work installations are implemented. I understand that this is to prevent emissions rather than stop incoming interference....

Mark

Thanks, Mark

I will read that one tomorrow.

... Bedtime now.

MichaelG.

I don't think that the "regs" have really caught up with VFD's yet. Anyway.

As far as I am concerned SY cable is armoured cable. "My bad", it's suitable for moderate mechanical stress the other type is usually used outdoors. It's not that flexible really. The ebay listing mentions the flex bending rad 20xdia which comes out at 200mm in your case. It's stiff enough to need each end of the cable anchored rather than just anchor with the wires. P clips may work out at the inverter end and metal ones can be used to earth the outer braid to form a shield. This can also be done with the copper cable. There may be enough room in the motor connection box to use them their as well or even on the outer surface of the box. The cable should be grounded at both ends some how or the other. There may be some way of attaching P clips to the inverter but the other way is to mount it on a board of some sort.

The SY cables also have an earth lead. That in itself will provide some shielding.

I'm not sure what to say about the cable rating. Mitsubishi suggest 2mm from 0.1 to 2,2kw. Your 1.5mm on the face of it is rated at 18 amps derated by 25% as it's multicore and yet more if the ambient is above 30C. So say 9 amps. That sounds like it's way too much but neglects skin effects which is important because high frequency is being sent down the cable. I haven't managed to find any info on that so far but do know from work on switch mode supplies that it's relevant. Mitsu are probably assuming that the full 15khz is going to be used and maybe a long length as well. I did find this recently while looking again, I gave up when I installed mine and had to use > 2mm anyway. 2.5mm is not much bigger than 1.5mm. 10.7mm as against 9.2mm.

**LINK**

Personally I feel your 1.5mm should be fine but on the face of it you might think you could use smaller to get more flex but normal current ratings don't account for high frequencies.

They also suggest 2mm for the mains feed to the inverter except for 2,2kw which needs to be larger, earth lead too. The peak current draw can be pretty high on these things but this lead is the one that actually goes to ground.

There is plenty of warnings about on using high switching frequencies on normal motors. There are all sorts of changes in inverter rated ones not just the addition of a fixed speed cooling fan. This tends to be ignored completely 'cause the things are so insanely expensive but it doesn't make sense to set the switching frequency any higher than needed. I've seen claims that this can increase heating effects by 10% but the main problem seems to be higher than normal voltage spikes in the motor and current flowing across the bearings.

John

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John,

I don't wish to be rude, or ungrateful, but:

I explained about my motors and their mounting to 'Quantum Controls' and asked for specific advice; which they have kindly given.

The Aciera head is like the one pictured here, dismounted, in the stand of an F3

https://goo.gl/images/jH21yF

It is, and must remain "portable" and therefore I have to arrange my wiring accordingly.

MichaelG.

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Edit: Image froms lathe.co.uk [as credited above]

Edited By Michael Gilligan on 18/08/2016 11:29:20

I can't say that I mentioned anything that prevents you from wiring as you want to. Just passing on some info from my own experience and recommendations from a rather major inverter manufacturer. Given the set up you have I know what I would do and yes it wouldn't entirely agree with inverter manufacturers general comments on wiring but only in terms of plugs.

John

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Mark,

Thanks again ... That's an excellent document [probably the best eight pages I have read on the subject so far]

Just a few minor observations which may be useful to others:

• On page 2 "effect" should read "affect"
• The statement on page 4: "Ground sizes allowed by the National Electrical Code (NEC) vary by conductor size, but, except in smaller cables, they are typically required to be significantly smaller than the circuit conductors." [although clarified later] is misleading. ... The ground sizes are not required to be significantly smaller; they are permitted to be significantly smaller !!
• On page 5, there is a very important observation which gives 'scale' to the discussion: "Opinions vary among VFD manufacturers, but Belden's research suggests that the benefits of symmetric design to prevent internally generated ground currents begins to be a design factor for motors above 50hp with very long runs, but is typically more significant in motors greater than 100hp."

MichaelG.

Michael,

Yes, I prefer that sort of information over "hear say" and assumption.

Over very short runs (less than 1200mm) I have to confess to using CG (common or garden) 4 core flex suitably sized on my lathes but I also use a motor side choke on all my machines to improve the life expectancy of my old fashioned motors.

Mark

PS. I have recently installed a crane in my garage and was thinking of taking some pictures and posting them for you regarding your interchangeable heads on this machine. I have been very busy but will try and get it done if you still have the lifting problem.

For info.

I have an early model [2.4i] of the Wi-Spy, from MetaGeek, which should serve as a basic interference detector.

**LINK**

http://www.metageek.com/products/wi-spy/?utm_expid=190328-158.sOrYCB04S9ag3e0x8LJbGw.0&utm_referrer=http%3A%2F%2Fwww.metageek.com%2Ftraining%2F

... Should be interesting.

MichaelG.

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Mark,

Yes, I would appreciate that [when you have time]

I have purchased a tidy-looking motorised hoist, but it's "intended" to be fixed to a 45mm square tube ... I'm seeking inspiration as to how to adapt this to travel X-Y [I have 'universal steel beams' supporting the roof for one axis]

MichaelG.

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Hoist: http://www.ebay.co.uk/itm/301565009664?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Edited By Michael Gilligan on 18/08/2016 22:32:47

??Rise times quicker than 0.146 nSec ??

John

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.

Oh dear ... Here we go.

For info. [not for debate, please]

Here are some 'interference' examples from the MetaGeek site:

https://support.metageek.com/hc/en-us/articles/200628894-WiFi-and-non-WiFi-Interference-Examples

MichaelG.

You would do better to test with an am radio receiver on long medium and short. Past that in areas where there may be problems life isn't that simple.

John

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Michael,

Pictures uploaded!