Which thickness CY cable do I need for 1.5kW spindle?

[bee]

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]

I would use 0.75mm or 1mm CY 4 core 0.75mm will be fine

[bee]

Thanks! I've ordered the 0.75mm because I it'll be a bit thinner and I assume nicer to handle.

[A_Camera]

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]

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.

[A_Camera]

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.

[JAZZCNC]

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.!!!!!. .

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]

6A for Control Signals.!!!!!. .

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

[A_Camera]

6A for Control Signals.!!!!!. .

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, 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.

[Lee Roberts]

Here is a chart showing what each size is rated at:



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