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View Full Version : Which thickness CY cable do I need for 1.5kW spindle?



bee
03-03-2016, 11:26 PM
So my Kress died (can't complain, it has served me very well), and I decided to upgrade to a 1.5kW Chinese spindle. So far it's been a lot of work to install it, and I still haven't decided where to place the vdf, so I do hope the new spindle will be every bit as amazing as it's reputed to be.

And now I found out I need CY cable between the vfd and the spindle, so I have some re-wiring to do (through cable tracks, oh!)

My question is which would be the correct core thickness of that CY cable for my use: 0.75mm, 1mm, 1.5mm?

Bernard

Clive S
03-03-2016, 11:42 PM
I would use 0.75mm or 1mm CY 4 core 0.75mm will be fine

bee
04-03-2016, 09:14 AM
Thanks! I've ordered the 0.75mm because I it'll be a bit thinner and I assume nicer to handle.

A_Camera
26-05-2016, 08:57 AM
Thanks! I've ordered the 0.75mm because I it'll be a bit thinner and I assume nicer to handle.
It is thinner and lighter but it should be 1.5mm2. 0.75mm is OK for control signals but actually too thin for the power.

Clive S
26-05-2016, 09:08 AM
It is thinner and lighter but it should be 1.5mm2. 0.75mm is OK for control signals but actually too thin for the power.I still think 0.75mm is fine the motor is 1.5Kw 3 phase and quite short. There are many people using that on this forum.

Lee Roberts
26-05-2016, 10:20 AM
Here is a chart showing what each size is rated at:

http://uploads.tapatalk-cdn.com/20160526/f420482ad3da64c758c92093e673714a.jpg

Here is a list showing the watts to amps conversions:

WATTS TO AMPS CONVERSION

60 Watts = 0.26 Amp
100 Watts = 0.43 Amp
200 Watts = 0.87 Amp
300 Watts = 1.30 Amp
400 Watts = 1.74 Amp
500 Watts = 2.17 Amp
600 Watts = 2.61 Amp
700 Watts = 3.04 Amp
800 Watts = 3.48 Amp
900 Watts = 3.91 Amp
1000 Watts = 4.35 Amp
1100 Watts = 4.78 Amp
1200 Watts = 5.22 Amp
1300 Watts = 5.65 Amp
1400 Watts = 6.09 Amp
1500 Watts = 6.52 Amp
1600 Watts = 6.96 Amp
1700 Watts = 7.39 Amp
1800 Watts = 7.83 Amp
1900 Watts = 8.26 Amp
2000 Watts = 8.70 Amp
2100 Watts = 9.13 Amp
2200 Watts = 9.57 Amp
2300 Watts = 10.00 Amp
2400 Watts = 10.43 Amp
2500 Watts = 10.87 Amp
2600 Watts = 11.30 Amp
2700 Watts = 11.74 Amp
2800 Watts = 12.17Amp
2900 Watts = 12.61 Amp
3000 Watts = 13.04 Amp
3100 Watts = 13.48 Amp
3200 Watts = 13.91 Amp
3300 Watts = 14.35 Amp
3400 Watts = 14.78 Amp
3500 Watts = 15.22Amp

.Me

Clive S
26-05-2016, 10:26 AM
Lee that is helpful but the chart does not show if the cables are in free space or bunched together in one sleeve as the cable will have to be derated when bunched because of heat build up.

Edit Lee the Watts to Amps conversion has to state the voltage I know you have it done at 230V

Lee Roberts
26-05-2016, 11:43 AM
Lee that is helpful but the chart does not show if the cables are in free space or bunched together in one sleeve as the cable will have to be derated when bunched because of heat build up.

Edit Lee the Watts to Amps conversion has to state the voltage I know you have it done at 230V
OK, to clarify:

Cg represents the derating factor for grouping cables.

A cable with a current rating of 6 amp installed in trunking alongside other circuits, that's circuits not cables!, would now have a Cg value, the Cg value is 0.57.

This means the cable current rating becomes: 6 x 0.57, that's 3.42 amp.

To add to this, you should note that the grouping factors are based on assumption, the assumption that all of the cables in the group are carrying their rated current.

So, if however a cable is not going to be carrying more than 30% of its grouped current rating, that cable can actually be omitted from the group rating calculation...

...an example, if you've got lets say 6 circuits in a group of cables but 1 of those cables is known to be operating below the said 30% consistently, you can safely calculate the group on the basis that it only consists of 5 circuits.

Here are some correction factors for multicore cable:

http://uploads.tapatalk-cdn.com/20160526/e108516602414c2d7a9e0568e1eab805.jpg


OK Clive, how did I do?

.Me

Clive S
26-05-2016, 12:08 PM
OK Clive, how did I do?Fine Lee I was not taking the p#'@s I just thought that the Voltage had to be added etc for the sake of people with no knowledge of sparky stuff.:beer:

A_Camera
26-05-2016, 01:52 PM
Lee, what works is not the same as what is safe and what is recommended.

https://en.wikipedia.org/wiki/Electrical_wiring_in_the_United_Kingdom

18513

That is a more realistic and better data, even if you step down one size, 1.5mm2 is what should be used. 0.75mm2 is for small desk lamps, not for motors. Then again, I know most people never really use their spindles at maximum load, so it is never really going to be a problem and in many cases even 0.5mm2 might be OK, but I think 1.5mm2 is the minimum if you want to play it safe. My 1.5kW is rated 8A and I am pretty convinced that saving on cable costs is not a good decision. Also, if you ever decide to use a vector controlled spindle you will notice that it pulls more current as well, so what is the point of under dimensioning the cable?

Lee Roberts
26-05-2016, 01:59 PM
Fine Lee I was not taking the p#'@s I just thought that the Voltage had to be added etc for the sake of people with no knowledge of sparky stuff.:beer:
I know mate :), I was only having fun, my ask of "how i did" was actually sincere as I only know what I've learnt in an unformal way, im no professional.

At the same time I thought it was a good cue for providing the knowledge, as like you say those conversions need to take the operating voltage into consideration if starting from the beginning and doing your own calculations.

.Me

A_Camera
26-05-2016, 02:02 PM
I still think 0.75mm is fine the motor is 1.5Kw 3 phase and quite short. There are many people using that on this forum.
Yes, I know many people use that, but 0.75mm2 is lamp wire, not for motors, at least not for motors of the sizes we are discussing. Yes, handling a 1.5mm2 is not as easy as 0.75mm2, but still, not that difficult if you know how to solder and connect. Also, when you crimp the VFD end (which I guess you do) it is considerably safer to use 1.5mm2 than the lamp wire. 0.75mm2 or 0.5mm2 is for control wires in this area, not power.

Then again, this is just my opinion. I know many people will disagree and many people use far too thin cables for convenience, price and for lack of better knowledge and that "it works", also because they read these forums and go for the "majority rule" principle.

Clive S
26-05-2016, 04:28 PM
Ok it is not lamp wire it is CY cable the smaller size is easier to connect into some of the small plugs and cable trays.
I see the chart you put up that is for domestic wiring and I agree with that.

The 1.5Kw is spread over the three cables as well.

But it is your opinion but not mine. I do use 1.5mm generally.

A_Camera
26-05-2016, 10:46 PM
Ok it is not lamp wire it is CY cable the smaller size is easier to connect into some of the small plugs and cable trays.
I see the chart you put up that is for domestic wiring and I agree with that.

The 1.5Kw is spread over the three cables as well.

But it is your opinion but not mine. I do use 1.5mm generally.
I call it lamp wire because the conductor is as thin as it is for lamps. The fact that it is shielded is a different matter. I chose 1.5mm2 for the power and 0.75mm2 for the control and low voltage wires. Admittedly, it was not that easy to fit the 1.5mm2 into the plug, but it is just a one time work, so once it is done in one end, everything is much better and easier. Crimping is simple and no bother at all. If the wires are too thin crimping cables shoes becomes insecure and problematic.

JAZZCNC
26-05-2016, 11:40 PM
It is thinner and lighter but it should be 1.5mm2. 0.75mm is OK for control signals but actually too thin for the power.

6A for Control Signals.!!!!!. . :whistle:

Don't worry Bee it will be fine. These spindles at full load only pull 8A. In practise and while heavy cutting they actually rarely pull above 5A. 0.75mm2 is rated 6A and this is very conservative rating. Again in practice and for the very rare occassions you do pull full load of spindle/VFD it will easily allow to pull 8-10A without any trouble. In case of Short Circuit the VFD it's self will protect you with it's Max current setting and then you have the Fuse.

Clive S
27-05-2016, 12:24 AM
6A for Control Signals.!!!!!. . :whistle:

Don't worry Bee it will be fine. These spindles at full load only pull 8A. In practise and while heavy cutting they actually rarely pull above 5A. 0.75mm2 is rated 6A and this is very conservative rating. Again in practice and for the very rare occassions you do pull full load of spindle/VFD it will easily allow to pull 8-10A without any trouble. In case of Short Circuit the VFD it's self will protect you with it's Max current setting and then you have the Fuse.
Common sense at last:beguiled:

JAZZCNC
27-05-2016, 01:16 AM
Common sense at last:beguiled:

Suppose Makes a change from talking bollocks. :devilish:

paulus.v
27-05-2016, 04:26 AM
I call it lamp wire because the conductor is as thin as it is for lamps. The fact that it is shielded is a different matter. I chose 1.5mm2 for the power and 0.75mm2 for the control and low voltage wires. Admittedly, it was not that easy to fit the 1.5mm2 into the plug, but it is just a one time work, so once it is done in one end, everything is much better and easier. Crimping is simple and no bother at all. If the wires are too thin crimping cables shoes becomes insecure and problematic.

Do you have a hair dryer at hand? Check the cable and power. Mine has 1700W and a 2x0.75mm2 cable. And is german made.


Now regarding the question in this thread, I would never use a 0.75mm2 "normal" stranded cable in a CNC machine. Since all the cross-sections are composed of thin wires with the same diameter, a larger cable will last longer. If/when half the wires of the 0.75mm2 conductor (only 10-12 of them) will be broken, probably the rest will blow. For a 1.5mm2 cable, three times the number of wires needs to be broken to come to the same situation.

Using special flexible fine stranded cables, even 3x0.5mm2 will be enough for a 3 phase 1.5kw spindle on a short distance :playful:

Here I attach some more charts...

A_Camera
27-05-2016, 08:41 AM
6A for Control Signals.!!!!!. . :whistle:

Don't worry Bee it will be fine. These spindles at full load only pull 8A. In practise and while heavy cutting they actually rarely pull above 5A. 0.75mm2 is rated 6A and this is very conservative rating. Again in practice and for the very rare occassions you do pull full load of spindle/VFD it will easily allow to pull 8-10A without any trouble. In case of Short Circuit the VFD it's self will protect you with it's Max current setting and then you have the Fuse.
You can't ONLY go only after currents, :rolleyes: if that was all that mattered we could use hair thin wires for all type of communications. You are blindly staring at one parameter only.

Generally speaking, yes, 0.75mm2 is enough for most cases for the spindle, but why use something as thin as that if 1.5mm2 is safer, stronger, not much heavier, better suited for the purpose and hardly much more expensive. Can you come up with ONE good reason other than most people don't continually use up more than 5A?

I chose 0,75mm2 for the control signals because that is what I have, apart from 1.5mm2 and FTP CAT6 cables (0.5mm2), so I chose the 0.75mm2. The FTP cable would be good as well, but I like the Ölflex cable more, it is easier to handle for the purpose.

A_Camera
27-05-2016, 08:44 AM
Common sense at last:beguiled:


Whatever rocks your boat...

To me, the common sense is NOT to use such thin wires for this purpose. It works, but it is AGAINST common sense.

A_Camera
27-05-2016, 09:21 AM
Do you have a hair dryer at hand? Check the cable and power. Mine has 1700W and a 2x0.75mm2 cable. And is german made.
Fine. Now, run that hair dryer for 8 hours non-stop and see what happens... :eagerness:

Hair dryers are NOT high frequency controlled equipment, they have a tiny motor and they are not designed to be run for more than a few minutes a time so you can't really take that as a good example. My drilling machines have 1.5mm2 cables, they are also German made, and none of them are over 1kW. Why? Because they are designed for sudden current rushes and for long usage time.



Now regarding the question in this thread, I would never use a 0.75mm2 "normal" stranded cable in a CNC machine. Since all the cross-sections are composed of thin wires with the same diameter, a larger cable will last longer. If/when half the wires of the 0.75mm2 conductor (only 10-12 of them) will be broken, probably the rest will blow. For a 1.5mm2 cable, three times the number of wires needs to be broken to come to the same situation.
That is yet another good argument for a stronger cable. On the other hand, if you handle the cable as you supposed to handle and don't bend it more than it is specified for *AND* use the cable type which is designed for the application (i.e. flexible cable chain use) than you should not have any broken wires during the life time of your machine. Remember that I am talking about quality cables, not the one used in the hair dryer.


Using special flexible fine stranded cables, even 3x0.5mm2 will be enough for a 3 phase 1.5kw spindle on a short distance :playful:

Yes, of course. I have never claimed otherwise. Just that I can't really see any *GOOD* reason for not using something stronger than 0.75mm2. Never the less, there is a group of people who prefer the easiest approach, which is using the thinnest possible cables. Beats me why, I don't understand that philosophy and prefer to have margins if I can. On the other hand... so far I have not had any electrical issues, and I don't expect to have any later on.

Clive S
27-05-2016, 10:11 AM
Yes, of course. I have never claimed otherwiseI thought you claimed it here:-



It is thinner and lighter but it should be 1.5mm2. 0.75mm is OK for control signals but actually too thin for the powerWell you appear to have jumped on the op's post nearly 3 months after he last posted and muddied the waters quite well.

I think you need to take a good look at your own machine before nit picking others.
I will not be posting any more on this subject. So please lets not take any more space on his post.

By all means start one of your own.

JAZZCNC
27-05-2016, 10:37 AM
Generally speaking, yes, 0.75mm2 is enough for most cases for the spindle, but why use something as thin as that if 1.5mm2 is safer, stronger, not much heavier, better suited for the purpose and hardly much more expensive. Can you come up with ONE good reason other than most people don't continually use up more than 5A?

I could but won't get into slanging match with someone so narrow minded. I'm also not saying I would have used 0.75mm2 because I wouldn't have. However only because I have 1.0mm2 & 1.5mm2 which use all the time. If I'd only had 0.75mm would have used it.

The point of my first post was more to re-assure the OP "Bee" that his choice, which he'd already purchased before you posted would be fine. This by now he surely knows because some Muppet started up the thread again 3 mth's after he posted.!!

A_Camera
27-05-2016, 12:49 PM
I could but won't get into slanging match with someone so narrow minded. I'm also not saying I would have used 0.75mm2 because I wouldn't have. However only because I have 1.0mm2 & 1.5mm2 which use all the time. If I'd only had 0.75mm would have used it.

The point of my first post was more to re-assure the OP "Bee" that his choice, which he'd already purchased before you posted would be fine. This by now he surely knows because some Muppet started up the thread again 3 mth's after he posted.!!

OK, so you would not use 0.75mm2, just want to comfort someone who bought the cable... well, the reason for the Muppet to start up the thread LESS than 2 mnts after Bees last post was to try to open the minds of those who are not sure, so they just follow the stream and go after the majority on these forums. I think that can hardly be called narrow minded, more like an effort to help. Considering the costs of the cable, and compared to the price of the CNC the "use what I have available" principle is really very narrow minded and wrong. Apparently you are more keen on name calling than admitting that I was right, there are ONLY advantages of a stronger, better cable, no disadvantages. You don't answer my question because there is just one answer. Anyway, at least in this post, you made it clear that the 0.75mm2 would have not been your choice, so basically, we actually agree.

...and in all honesty, if you really know what I think you know, then I don't think you would have used 0.75mm2 cable if that was all you had at home. I think you would have done the same I would have done, ordered 1.5mm2 and possibly used the thinner one until the better one arrives... :toot:

Like I said, what works and what is right are not necessarily the same.

paulus.v
27-05-2016, 01:00 PM
It is thinner and lighter but it should be 1.5mm2. 0.75mm is OK for control signals but actually too thin for the power.

You do not say that you prefer or recommend using thicker cables to be on the safe side or you normally have them at hand or you don't mind wasting a valuable metal with finite resource here on earth. But you say that a 1.5KW spindle cable should be 1.5mm2 and the control cables 0.75mm2 (when most control cables are 0.25mm2). This approach is all wrong!

A_Camera
27-05-2016, 01:17 PM
I thought you claimed it here:-


Well you appear to have jumped on the op's post nearly 3 months after he last posted and muddied the waters quite well.

I think you need to take a good look at your own machine before nit picking others.
I will not be posting any more on this subject. So please lets not take any more space on his post.

By all means start one of your own.
Sorry for disturbing the peace, but the way I see it is that I was not the one throwing the mud. I made a short one line comment and not criticized you or anyone else, all I said was:


It is thinner and lighter but it should be 1.5mm2. 0.75mm is OK for control signals but actually too thin for the power.

Actually, going by the book (the manual of my VFD), even that statement is wrong because for the 1.5kW the cable should be 2.5mm2 but that is simply too thick and really over engineered, so 1.5mm2 is more realistic.

The thread would have been dead by now but apparently you, and some other people could not stay away from it, so it lives on. I don't mind that, but it would be more useful if people could keep their heads cool and would not throw mud just because I don't follow the stream and have a different opinion. I was also NOT nit picking on other people's machines, but you have to remember that this forum is visited by many total newbies who experience a lot of electrical issues. One way of helping is to give factual advice, not emotional.

BTW, Why are you saying that I need to take a good look at my own machine? I am looking at my machine, and regarding electrical installations, I am not only using several DVMs but also an oscilloscope, and in fact, occasionally two oscilloscopes at the same time. Apart from that, I am reading the manuals of every item that comes with a manual, not just guessing and go after what other people use or claim on the internet. Never the less, I could have missed something, so if you have found something wrong please let me know. I am in the process of upgrading and welcome all comments. I have no emotional attachments to my machine so I am ready to change almost anything if it is for the better. :eagerness:

You are though right about one thing, there is not much more to say about the subject, though it may pop up again, or someone might start a new thread with the same question...

A_Camera
27-05-2016, 01:49 PM
You do not say that you prefer or recommend using thicker cables to be on the safe side or you normally have them at hand or you don't mind wasting a valuable metal with finite resource here on earth. But you say that a 1.5KW spindle cable should be 1.5mm2 and the control cables 0.75mm2 (when most control cables are 0.25mm2). This approach is all wrong!
Yes, well... many people have electrical issues...

I think that line is pretty clear, but sure, this is the internet, so if something can be misinterpreted you can be sure someone WILL misinterpret it and start a stupid fight about it.

Regarding the environmental issues... well... the way I see it is that basically EVERYONE on this forum, and every other similar forum, is wasting valuable metal with finite resources here on earth, because hand on your heart... how many of us MUST have the machines we have? To me this is just a hobby, as it is for most people on these forums. You, and everyone else on this forum (including myself) are HUGE contributors to global warming, the using up of finite resources and everything else environment activists can come up with. So, please don't beat your chest and be proud about yourself just yet or accuse me for being an enemy of the earth... you know nothing about me or how I am living, so leave that out.

Besides, who says that the cable must be wasted? It can be used in another project or sold to somebody else for re-use.

JAZZCNC
27-05-2016, 02:07 PM
Apparently you are more keen on name calling than admitting that I was right, there are ONLY advantages of a stronger, better cable, no disadvantages. You don't answer my question because there is just one answer. Anyway, at least in this post, you made it clear that the 0.75mm2 would have not been your choice, so basically, we actually agree.

I wasn't name calling more stating the obvious. IMO it's muppet with over active Ego that posts reply to question which had been answered already and acted upon by the OP months ago.!
I don't doubt your knowledge of electricker and in principle Yes your correct so if your Ego needs a massage I'll glady ablige and say I agree that 0.75mm shouldn't be first choice.
However the fact still remains 0.75mm2 would and will work perfectly fine. All your arguments regards Cable strength, ridgidty etc are mute because it's stupid thing to rely on cable for strength when it should be supported with bracket. The Only thing that matters is if cable can handle the load of the device it's powering while in prolonged use and clearly it can.


...and in all honesty, if you really know what I think you know, then I don't think you would have used 0.75mm2 cable if that was all you had at home. I think you would have done the same I would have done, ordered 1.5mm2 and possibly used the thinner one until the better one arrives... :toot:

Why would you presume to predict what I would do.? . . . I don't know me so you or anyone else stands NO chance predicting my actions.!!
If I'd took the time effort to fit it then I'd consider it safe and it would stay on. The ONLY time I might do this is in emergency situation to get machine up and running.


Like I said, what works and what is right are not necessarily the same.

This is contradiction.!! . . . . . If it's working Correctly then it's Right.!!

lucan07
27-05-2016, 02:18 PM
This is contradiction.!! . . . . . If it's working Correctly then it's Right.!!

Glad to hear it JAZZ I was almost ready to swap out the 6560 on the Sieg conversion but now you say its right I will leave it where it is!:victorious:

JAZZCNC
27-05-2016, 02:23 PM
Glad to hear it JAZZ I was almost ready to swap out the 6560 on the Sieg conversion but now you say its right I will leave it where it is!:victorious:

Performance upgrade is different animal.!! . . . Fatter cable won't make spindle go any faster.:stupid:

A_Camera
27-05-2016, 02:26 PM
This is contradiction.!! . . . . . If it's working Correctly then it's Right.!!
No it's not. But I am tired of this discussion, so I will just leave it at that.

...and yes, being called narrow minded is indeed name calling and no, I have no ego problems, it seems that my short comment hurt other peoples ego, not mine.

A_Camera
27-05-2016, 02:32 PM
Performance upgrade is different animal.!! . . . Fatter cable won't make spindle go any faster.:stupid:


...and who said that fatter cable makes your spindle run faster?

lucan07
27-05-2016, 02:51 PM
Performance upgrade is different animal.!! . . . Fatter cable won't make spindle go any faster.:stupid:

Neither will a different board I will still have a 500w DC motor 200-5000rpm, steppers can alread run faster than size of machine can accomodate, and it hasn't cocked up yet, it leaves that to me I can do that all on my own!:victorious:

lucan07
27-05-2016, 02:53 PM
...and who said that fatter cable makes your spindle run faster?


Thats a dig at me and my 6560!

JAZZCNC
27-05-2016, 10:53 PM
Thats a dig at me and my 6560!

Actually wasn't having a Dig just stating facts.!!

Lee Roberts
27-05-2016, 10:55 PM
Whatever rocks your boat...

To me, the common sense is NOT to use such thin wires for this purpose. It works, but it is AGAINST common sense.
I personally work to the formula: "Nothing Built Strong, Ever Broke"

Following that seems to have worked for me all these years so I know what your saying :-).

.Me

Doddy
28-05-2016, 01:13 AM
Not replying to any single post here:

Considering only resistance (okay, a motor is largely inductive - it makes the maths slightly trickier, but there is a significant resistive element to the motor and the basic premise remains)

Simply, given the same conductor type, 0.75mm2 cable has a higher resistance per unit length than 1.5mm2. Similarly, 1.5mm2 has a higher resistance per unit length than 2.5mm2. That fact is irrefutable.

The power dissipated in the cable run is proportional to the resistance.

Also, the voltage drop across a cable run is proportional to the resistance. The higher the resistance, the greater the voltage drop across the cable run.

The voltage drop across the cable run is proportional to the square of the current drawn. So, under load, with greater current draw, the voltage drop across the cable run increases at the square-law of the current, and implicitly, the load.

The voltage at the spindle is the terminal voltage of the VFD, minus the voltage drop across the cable run.

The mechanical power provided by the spindle is proportional to the terminal voltage of the VFD.

So, the lower the CSA of the cable run, the lower the voltage at the spindle. This drop increases as the load increases. This impacts directly the available power of the spindle. Cable CSA is related to performance.

Of course, the standard cable ratings easily found on the interweb don't consider the performance of the spindle, only the safe operating mode of the cable under domestic and industrial applications - given the heating effect of the dissipated energy on the cable, and - importantly - the longevity and integrity of the insulation. You might find that a particular cable works, but that the insulation fails after prolonged use.

The spindle manufacturer will provide a design specification for the spindle. This /should/ (I have to provide that caveat for our illustrious Chinese manufacturers who are not unknown to put anything that sounds good in the manual without reference to reality) allow the spindle to operate as designed. It is not unreasonable to expect then, that if you compromise that design, you'll compromise the performance of the spindle.

Finally (I need to get back to the bottle of wine), don't design a system assuming any strands on a multistranded cable will fracture - at that point the mechanical design of the system has already failed and catastrophic failure of the cable will occur in short time.


An analogy. If an architect specified a 152x89 RSJ. Would you chose to replace this with a 127x76 RSJ that you had lying around? It might well work, the building would probably stay upright after you've finished it. Hey!, the architect is clearly a fool.

lucan07
28-05-2016, 01:59 AM
I might be a bit fick but did you just say "Fatter cable will make spindle go faster"?

Doddy
28-05-2016, 07:37 AM
I might be a bit fick but did you just say "Fatter cable will make spindle go faster"?

Not on a VFD driven spindle - it'll give more torque. Thinking about my old DC spindle (not really the case discussed here) - in that case yeah more spins.

Groan: That was bad wine last night.

bee
29-05-2016, 10:20 PM
Right. Well... this has all taken quite a turn. Who'd have thought all hell would break loose several months later. I'm the OP and just to justify my choice of cable, I must admit I had no idea what these cables looked like in real life, so getting the lightest possible seemed like the right thing to do. It's working very well, and since there still are forum voices that say it's okay, I'll stick with it. I do understand that more is better in these things, but it's all installed and, I'd like to think, behind me.

It's been interesting, though, and thanks to all. This is a great and helpful forum!

Bernard

Doddy
29-05-2016, 10:25 PM
Hell?, that wasn't hell!, try posting something in the RFQ section!

Glad it's all worked out for you :)

JoeHarris
19-03-2017, 12:10 AM
An analogy. If an architect specified a 152x89 RSJ. Would you chose to replace this with a 127x76 RSJ that you had lying around? It might well work, the building would probably stay upright after you've finished it. Hey!, the architect is clearly a fool.

Not wishing to fuel the fire, but what cross section cy are people generally using between driver and stepper?! (genuine question!)
Signed foolish architect

ps. This video is quite useful for those with less experience when it comes to connecting steppers to the cable itself, I would be interested to hear comments on his methodology from those who have done this many times before... - https://www.youtube.com/watch?v=Xbiipb6nnZg

Clive S
19-03-2017, 01:03 AM
Joe I generally use 4 core 1mm CY cable and earth the screen to a star point in the control box and I don't see the point of stripping such a lot of cable back 6" is more than enough. But I make these for the back of the motor21164

JoeHarris
19-03-2017, 01:34 AM
Joe I generally use 4 core 1mm CY cable and earth the screen to a star point in the control box and I don't see the point of stripping such a lot of cable back 6" is more than enough. But I make these for the back of the motor21164

Thanks Clive, I thought he stripped a lot off! Do you 3D print those yourself?

Clive S
19-03-2017, 08:43 AM
Thanks Clive, I thought he stripped a lot off! Do you 3D print those yourself?The white one I printed, the black one was milled from one of those fencing posts made out of car tyres. They are 100x100 square so I band-sawed it down the centre then it was possible to get one out of each half. The trouble with it is that the stuff if full of bubbles in the centre but they were fine. I have also made them from various plastics which are very nice.

They are available like http://www.soigeneris.com/nema_23_stepper_cover-details.aspx But I have seen them for about 13 euro from Europe somewhere.