CNC for dummies...Some electrics advice please...pretty please...

[andy586]

I have a router build coming along nicely but have hit a vfd shaped roadblock.

I acquired a 2.2kw spindle and huanyang vfd. Wired up the vfd (R,T and Earth) to a 13a plug, plugged in, vfd went bang (had ringing in ears for some time!). Not great. Made much worse by me being a stupid **** and not unplugging other stuff from sockets first. Results....£400 television now dead and hdmi port on 2 month old motherboard also dead. VFD on its way back to Portsmouth as we speak. Router has already had blood and sweat out of me...tears don't seem far off.

Been looking at alternative VFDs and settled on a TECO L510, only to notice the input current for 2.2kw is 21a....bugger...me being a **** again and thinking I was ok off a 3 pin 13a plug because the motor was rated to 10.5a. So would I have to get a sparky in to add a new circuit to run a 2.2kw vfd? If so, I think I will have to bite the bullet and go down to something smaller that will run off 13a plug (0.8kw I presume?). More money that I don't have but probably quicker and cheaper to downgrade spindle than to pay for work being done.

Also, only just learning now about shielding/noise etc. Firstly, my stepper wiring is all unshielded (7/0.2 and 24/0.2). Is this an absolute no-no or just a bit of a no-no? Secondly, when reading other posts , people refer to their frame being grounded. How do I go about this? I don't have any central wiring points or anything...just running stuff off 3-pin mains sockets. The TECOs have a built in filter. Is anything else required?

So to summarise:

1. Maximum spindle/vfd running off 13a plug?
2. Unshielded stepper wiring ok (just about)?
3. How to ground frame?
4. Anything in addition to built in filter and shielded motor cable required? While I'm at it, anyone know a good place to go for the cable?

Many thanks for your help guys....

[Clive S]

1. Maximum spindle/vfd running off 13a plug?
2. Unshielded stepper wiring ok (just about)?
3. How to ground frame?
4. Anything in addition to built in filter and shielded motor cable required? While I'm at it, anyone know a good place to go for the cable?

1. Nothing wrong with running 2.2kw off 13A plug. Think 3Kw washing machine
2. You do need shielded cable to stepper and vfd I use 1mm CY cable. others might say 1.5mm
3. Connect the frame to your earth star point if possible.
4.This is one place for it http://quickbit.co.uk/cable/CY-cable/CY-Cable-1mm-4-core
2. The shield on the cable is also earthed at the star point.

Where did you connect your earth to on the vfd. ..Clive

[Jonathan]

1) 3kW
2) If un-shielded cable is used to steppers, they might interfere with other things (e.g. limit switches, your radio), but if those other things are shielded then with a small amount of luck you can be fine.
3) As Clive said - so just wire all the earths back to one point, then connect that to the earth pin on mains socket.
4) Probably not.

[JAZZCNC]

Everything Clive said except not using Quickbit for the cable.? I've tried them twice now just to be sure and both times the cable was cheap rubbish. It's brittle with poor markings.
CSE cables is much better quality and not much more expensive. CY Cable (http://www.csecables.com/acatalog/CY-Cable.html)

Don't skip the shielded cable it will only come back to bite you and make sure you ground the steppers and Limit sheilds at one end only in the control box and to the main Star ground point.

[andy586]

Thanks very much for the input guys...

In response to clive's question about the earth wiring, I had wired from a 13a plug to R, T and E (the E was on the same row, after the U,V,and W (not either of the ones attached directly to the casing)).

I will go ahead with the 2.2kw setup then...thats a relief that the spindle I already have is of use.

I had better go ahead with shielded cable all round then as Lady Luck seems to be doing the dirty on me at the minute...

I'll be back in a week or so with photos and a full build log (something of a 'how not to build a cnc').

Thanks again guys...really appreciated. Finishing line in sight!

[JAZZCNC]

Finishing line in sight!

OH NO it's only just begun.!! . . . . . Come back in 12mths and tell us how far off finished. .Lol

[andy586]

LOL...yeah..i'm starting to change my mindset from 'last few hurdles' to 'one hurdle at a time'.

Am I ok with this? https://www.inverterdrive.com/group/AC-Inverter-Drives-230V/Teco-L510-203-H1F-P-A/

Out of interest, why is it that I can get away with it on a 13a plug if it states 21a input current? Is that because it won't draw that much in practice?