I'm researching some electronics stuff for my CNC project and was looking at an enclosure to use with the following kit:
Zapp Automation Ltd - Stepper motors & Stepper Motor Drivers - Servo motors and Servo Motor Drivers - Ballscrews & linear motion products. : High Voltage Driver Kit Three (Three axis) [3axiskit3] - £412.38
Possibly I am fortunate in having a 27U rack I use for a few servers in my office/workshop and was thinking this might also be a perfect place to house the drivers and PSU's using something like:
Buy Rack Fitting Cases & Enclosures Rack Mount enclosure,6U 465mm Black RS PF-19 6U D4 online from RS for next day delivery.
Question is, assuming I will have my VFD/Spindle unit and cabling well away from the rack (underneath the CNC machine workbench), will the driver and PSU stuff be OK in the same rack as my servers and not interfere with my servers? Also assume I will be getting decent quality shielded cables.
I canít see this being a problem, more so if you use shielded cables. I would try and keep the cable runs as clear as you can; I would maybe look to keep the rack under the cnc with the other stuff though.
I did a build in a pc case and had everything in that enclosure, including the pc stuff without shielded cables and didnít have any problems. I know others have done this as well, Iím currently working on an enclosure for the same again featuring an Atom based system so hoping all will go well with that, I cant actually recall anyone having an issues with the PC next to the drivers and so on but I think it does happen for some, may have to try it and see.
Sounds like my rack may be housing more than servers now and save me some workshop real estate.
Good idea on using drive enclosures for your stepper drivers. I have some of those spare, so will be "borrowing" that idea :-)
I guess the interference problems people experience (steppers skipping etc) come from the VFD and its cables being in the same cable run as poor quality unshielded stepper cables - Tesla vs Edison again? ;)
Sorry didnt mean to post so many pics...i should have thought about it, the only problem i had doing it that way was the 542's are a little wider than a hard drive and as luck would have it the side of the rom bay lined up nicely with where the side of the hd bay needed to be. I did have a 4u nocking about i could have used and i did strip it down ready to start hacking it up but it was old and grey/cream and a new tower was only £20 and looked a better option at the time. I did plan to put the fuse holders, l.e.d extensions for the drivers and so on in the front bay panels but i nver really got that far, the case and bits are still sat on a shelf collecting dust.
I just used some ali angle for the side plates the drivers sit on, looked cool i guess.
Re the VFD cables, i've not got one or any experience using one so cant really comment sorry.
Shielded cabling, proper star-wired earthing and pull-ups on all inputs whether used or not, is all thats needed... a VFD is nothing more than a big switch-mode PSU. Problems that people have come from running unshielded power and signal side by side for long runs (> a few inches), creating ground loops by not wiring everything back to a common point (or grounding both ends of a shield), not grounding things at all, or in worst cases, powering different parts of the system off different ring mains on different phases (can induce huge ground offsets). Ok the latter is very rare but I discovered it in a commercial premises wired by cowboys (and it did have a P-certificate)
I didn't want anything guassing my precious server data and the VFD is not going in the rack, just the PSU, drivers and possibly the controller. Just wanted to check in case I was throwing the equivalent of a tesla coil in there ;)
I don't have 3 phase, so I don't think your latter scenario will apply (not yet anyway ;) ), although I was thinking of running a seperate wiring feed to the VFD (and possibly the rest of the machine's electronics) from my consumer unit (I have a spare 32A RCD), just to keep it isolated from the rest of my "stuff".
Very important you use Star grounding and run all earths and shielding back to this star point. That includes the VFD and it's cable shielding.
What I do is have a mains pickup point in the control box with earthing block and pick the VFD power and earth from this point but still keep it outside the cabinet.
The separate feed is a good idea helping to keep the marriage out divorce courts after the Mrs puts Air drier on just when machines at full chat 10hours into a job and POP.
I agree with Jazz.
My own setup is:
- Consumer unit with dedicated 32A MCB, routed to
- 45A DP Isolation Switch (near work area), routed to
- Emergency Stop contactor, routed to
- Distribution point (small metal electrical cabinet, with 3 buss bars, I made it but a cheap 4 or 6 way domestic consumer unit would suffice too and give option of individual fuses/MCB).
The earth buss in that cabinet is my star point. Power to everything comes from there.
Lathe VFD is wall mounted and fed from there
Control box under desk is fed from there,
PC is fed from there.
Mill starter contactor fed from there.
Lathe and Mill chassis are earthed back to there.
Mill (currently non-VFD) motor and mill head individually earthed back to mill chassis (star of stars) so I dont rely on bolted joints to make earth connections
There is a seperate 'normal' spur off the main Consumer unit for powering other intermittent stuff like soldering irons, the bench grinder, and the fan heater!
When I eventually finish my new workshop I'll transfer this pretty much as-is except everything will come from the distribution point which I will replace with a 6-way RCD consumer unit to provide local isolation/fusing. The existing Isolator will stay in the garage and the armoured cable to the workshop will feed from there.
Sage advice as usual.
BTW - if you have time I have a couple of other areas I'm looking into:
1. I have a spray gun (also powers my airbrush) compressor and was thinking of using this for tool cooling/chip blowing - I notice Jazz you mentioned misting in another thread and am guessing this is just essentially atomising lubricant/cooling fluid into the air stream? I should be able to whip up a suitable nozzle if that's the case.
2. I'm also looking to run a 2.2Kw water cooled spindle with an arrangment of PC cooling rads (2xdual 120mm left overs from PC watercooling), which should bring the water in the curcuit+tank down to ambient air temperature. The tank will likely be somewhere around the 10-15L capacity mark, dependant on the room I have left under the workbench.
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