Thanks for pointing out this thread it is very informative and anyone contemplating buying a spindle should read this first before spending any money, I for one will read it more that once before placing an order again.
I have just ordered a VFD and water cooled spindle, Now to save cost and more important clutter I was thinking of just putting a large water tank under the table instead of a radiator and fan for cooling. How large a tank will I need? will 20 litres be large enough and how many litres a hour will the water pump have to pump to keep the spindle cool if worked hard like cutting aluminium? and if I ran antifreeze as coolant what percentage of antifreeze to water will I use?
Last edited by Bush Flyer; 09-01-2014 at 09:14 AM.
Cooling requirements greatly depend on how much power you draw from the spindle, but in general people use these spindles at well below their rated power, so you can get away without much to cool it. 20 litres should be fine - that's about what I use.
As for the pump, it's easy to calculate if you know how much power to dissipate, but knowing that is not so trivial. If you get something like this one it will be fine:
Aquarium Fish Tank Pond Submersible Water Pump 3000L/H | eBay
Thanks Jonathan, I've put the pump on my watch list, but will try to get a new one first, all parts are coming from the UK except the spindle mount but I am waiting on a reply from a supplier in the UK to get back to me so should not be to long and I will be back up and running all going well.
I'm about to order wiring for the new spindle and was wondering should I buy CY 4 core 1.5mm cable for the spindle and CY 3 core 1.5mm cable for the power to the inverter or could I reduce the cable down to 1mm. I have been looking for a diagram for the wiring and have found some very conflicting diagrams, but I could not find one diagram with cy cable and where to connect the shield then I found one site saying do not use cy cable for mains connection the more I read the more confused I am getting so I will rely on what is said here.
The VFD is 1.5kw HUANYANG VARIABLE FREQUENCY DRIVE.
The motor is a, Germany Imported Bearing, water cooled spindle 0.8Kw
The best information that was pointed out to me was this thread http://www.mycncuk.com/forums/router...vice-more.html
But it did not tell me if I should use CY cable to power the VFD and it did not show the earth and the shield wire.
This is the cable calculator that I used with a 3% volt drop. http://quickbit.co.uk/swa-cable-calculator.html and it always comes out at 1.5mm ?
I apologise for asking simple questions, but wiring and setting up of this is out my comfort zone.
Last edited by Bush Flyer; 10-01-2014 at 12:54 PM.
I have used cy cable 1mm 4 core from the inverter to the spindle, 3 cores are for driving the spindle and the fourth core is to earth (my spindle has a 4 pin socket on it) on mine pin 4 was not connected to anywhere, I took the top off and soldered a wire from pin 4 to one of the socket mounting bolts on the spindle (I had to put a longer bolt in and then use a nut on the inside).
The shield on the cy cable is only earthed and the inverter end.
The mains cable to the inverter only need 1mm standard 3 core flex. ..Clive
The Following User Says Thank You to Clive S For This Useful Post:
Last edited by Jonathan; 10-01-2014 at 02:22 PM.
I would have a look at various manuals for major inverter manufacturers to see what they say, these can be viewed or downloaded as pdf's.
For example an ABB manual says for 1.5kW the input cable should be 2.5mm^2, motor cable should be 1.5mm^2
(recommended for input cables also)
Symmetrical shielded cable: three phase conductors, a concentric or otherwise
symmetrically constructed PE conductor and a shield
A separate PE conductor is required if the conductivity of the cable shield is not
sufficient for the purpose"
So in terms of CY cable that's 3 core cable for the motor using the outer as the earth conductor and screen, this should be connected at both ends to obviously act as an earth conductor and to give 360 degree connections for EMC shielding (that's what CY glands are for). If the CY screen is of less cross sectional area than the inner conductors then another core should be used for the earth, i.e. 4 core cable or a separate earth cable run on the outside.
The supply cable could be 4 core armoured.
Before anyone jumps on the well known idea about connecting screens at one end only I suggest you do a search for EMC cable screening first.
Last edited by EddyCurrent; 10-01-2014 at 03:29 PM.
Bear in mind that ABB's recommendations for cable size are probably trying to cover themselves for most applications, whereas our application is quite specific. For the motor in question, the cables are quite short and the motor will spend most of its life operating well below the rated power. I therefore wouldn't be concerned with recommending 1mm^2 cable in this instance.
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