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View Full Version : Do you need to water cool erhm a water cooled spindle?!!



HankMcSpank
01-10-2013, 06:30 PM
Just wondering what the consensus is here?!

I think it was Jonathan that said the Chinese spindle were about 80% efficient, so for an 800W spindle surely I'd be looking at a meager 160W heat dissipation, therefore for short jobs (say 20-30 minutes), do I even need to bother with all the pipes plumbing and copious amounts of 'watta'?

My thinking here is the spindle body is one helluva heat sink, as is the spindle mount & the Z axis aluminium backplate...so perhaps for short milling jobs (as I typically do), I might not even have to bother?

GEOFFREY
01-10-2013, 07:50 PM
Hi, I told you in your other post that I have been running a WC spindle for about 10 years and have never bothered connecting up the water supply. I do keep my eye on the spindle body temp (It only ever gets hand warm, and that after about 30 mins routing. When I bought my machine I was given an instruction book which recommended allowing the spindle to run for about 10 mins before doing any work in order to enable the spindle to warm up!!! If your spindle gets hot in use you need to water cool - if it only gets moderately warm, then as you say there is enough mass to conduct any heat away. That is my opinion anyway. G.

~andy
02-10-2013, 11:40 AM
I have water cooling, but only turn on the pump if it's doing a long stint. Just having a bit of water in the system may help even if the pump isn't on.

So, I wouldn't worry about not having water cooling. Equally, it's really not that much of a hassle to add water cooling.

JAZZCNC
02-10-2013, 11:58 AM
Hank my WC pump expired and I didn't notice, the machine cut 20mm Ali job for 2.5hrs and still spindle was only just a bit hotter than normal so I wouldn't worry about it for 30min jobs. . . . Put it this way If my pump wasn't switched on By VFD I wouldn't bother for short jobs.!

HankMcSpank
02-10-2013, 12:42 PM
Thanks guys... I'm just trying to avoid the extra pipes, buckets, relays & wiring! It sounds like I should be able to get away with it for the type of usage my spindle will see.

JAZZCNC
02-10-2013, 01:51 PM
.. I'm just trying to avoid the extra pipes, buckets, relays & wiring!

That said for sake of 2 pipes & bucket it may be worth doing for long runs, better having the option to do it than not.
Regards Relays then Most VFD's have a in-built relay for switching external stuff so just use this. It also saves pump wear has it only comes on when spindles spinning.

Jonathan
02-10-2013, 03:25 PM
Just try it and see.


JI think it was Jonathan that said the Chinese spindle were about 80% efficient, so for an 800W spindle surely I'd be looking at a meager 160W heat dissipation

I feel I should clarify this. The spindle is an induction motor, so the efficiency varies somewhat. The efficiency will depend on the load and the speed, so at some point it probably will be 80%. The efficiency will be much lower at low load, but the input power is much lower so overall the power dissipation will not be that great.
I think you're mainly cutting PCBs, so the power required from the spindle is tiny - most of the power is just supplying the losses (bearings, magnetising current etc) so if you just leave the spindle on not cutting anything and see how long it takes to heat up, you'll have a pretty good idea of how long you can use it cutting PCBs.

The situation's very different if you do draw near full power - it will heat up very quickly, but it takes a bit of doing to make a machine for which the spindle power is the limiting factor...

HankMcSpank
02-10-2013, 08:48 PM
Ok, thanks to all.

I've now ordered a Toshiba VFD from Italy (as per silyavski's recommendation in this thread - http://www.mycncuk.com/forums/routers-spindles-controllers/6533-800w-spindle-noise-controlling-remotely.html), here's the one I went for....

INVERTER VETTORIALE TOSHIBA 0,75 kW 230 Volt MONOFASE USCITA MOTORE TRIFASE 1 HP | eBay (http://www.ebay.it/itm/INVERTER-VETTORIALE-TOSHIBA-0-75-kW-230-Volt-MONOFASE-USCITA-MOTORE-TRIFASE-1-HP-/261167369803?pt=Elettronica_Industriale&hash=item3ccec9ce4b&clk_rvr_id=527296515222&afsrc=1) (I'll never go larger than an 800W spindle, so this VFD ouight to fit my needs well)

In the meantime, my thoughts turn to the spindle wiring - I've already got an 800W spindle but there was no information supplied, with it - I'm figuring it's likely that these water cooled spindle all have common wiring, so can anyone please tell me what the 4 pins are...

http://hostmypicture.com/images/spindlesoc.jpg

I've seen reference on the net to 'U' 'V' & 'W' for the spindle pins...are these just arbitary abbreviations give to the three phases?

JAZZCNC
02-10-2013, 08:59 PM
I've seen reference on the net to 'U' 'V' & 'W' for the spindle pins...are these just arbitary abbreviations give to the three phases?

Those are the correct abbreviations for each phase. The forth wire won't be connected to anything.
Just wire to 3 connectors and if runs in reverse swap any 2 wires. . . Thats it.!!

HankMcSpank
02-10-2013, 09:08 PM
Those are the correct abbreviations for each phase. The forth wire won't be connected to anything.
Just wire to 3 connectors and if runs in reverse swap any 2 wires. . . Thats it.!!

but I don't know which pins on my spindle are actually U V & W.....so was hoping someone could say by referencing from the keying prong? (assuming they are all standard?)

Jonathan
02-10-2013, 09:11 PM
but I don't know which pins on my spindle are actually U V & W.....so was hoping someone could say by referencing from the keying prong? (assuming they are all standard?)

It's arbitary. Just connect the 3 spindle power wires to U, V and W in any order and all that will happen if the order is 'wrong' is the spindle will spin the wrong way. If so, then as has been said, just swap any two of U, V & W.

JAZZCNC
02-10-2013, 09:14 PM
Cheers Jon saved me some typing. .:encouragement:

Jonathan
02-10-2013, 09:44 PM
It's occured to me that you might not be sure which are UVW and which is not connected (or earth)? If so then just use a multimeter, set it to measure resistance and check the resistances between all 4 pins - you should find that 3 of them (UVW) are virtually identical, and one is open circuit.

HankMcSpank
02-10-2013, 09:47 PM
It's arbitary. Just connect the 3 spindle power wires to U, V and W in any order and all that will happen if the order is 'wrong' is the spindle will spin the wrong way. If so, then as has been said, just swap any two of U, V & W.

I'm obviously having a bad (blonde?!) day.... that's my point, I have no idea which of the four pins on the spindle's connector socket are the actual spindle's power wires (that was the main thrust of the photo earlier ...if those sockets standardized, I'd hoped someone might enlighten me which 3 of the 4 are used)

Jonathan
02-10-2013, 09:50 PM
Option two is unscrew the connector and have a look. Whilst your at it you could solder on an earth cable.

HankMcSpank
02-10-2013, 10:00 PM
Option two is unscrew the connector and have a look. Whilst your at it you could solder on an earth cable.

Sounds like option two it is! (I've used more energy asking on forum than getting a screwdriver out! lol)

Re soldering an earth cable onto the spare pin ...is this towards connecting an earth to the spindle's casing?)

Jonathan
02-10-2013, 10:03 PM
Re soldering an earth cable onto the spare pin ...is this towards connecting an earth to the spindle's casing?)

Yes, so you'd want to unscrew the endcap, drill and tap a blind hole in it inside and use that to secure the cable.

HankMcSpank
02-10-2013, 10:43 PM
Just wondering what the 'win is' by connecting an earth in the way you suggest?

The (aluminium) spindle mount conducts & the spindle chassis itself is conductive ....... the spindle mount is secured to the aluminium Z axis backplate...& I actually ground the backplate (for auto Z tool tip zeroing purposes)...therefore my spindle's casing is essentially grounded (albeit in a somewhat round about way!)

Jonathan
02-10-2013, 10:59 PM
It's just generally a bit neater than having a separate wire poking out to the spindle mount.

As you've already grounded the Z-axis, be careful regarding ground loops...