Earthing?

[JAZZCNC]

You can fit a braking resistor if the driver black box has provision for a braking resistor. A braking resistor dissipates unwanted energy and is one of the reasons a body might chose thicker wiring.

Exactly Clives point I think.!!! . . . There isn't a blood option for braking resistor on AM882 and tell the last time you or anyone else seen Nema 23 3Nm stepper motor fitted to Minimill using braking resisitor.!! . . . . . STOP TALKING SHIT.

[Edward]

Hahaha, this is getting interesting:)
In the EM806 and AM882 don't you have an over-current cut off with the red LED blinking? I think you really have to push them really hard, for instance, with high deceleration to get to that stage. I don't intend to drive this machine too madly:)
Also, I guess the psu will be able to cope with a bit of back EMF if I feel too adventurous...

Edward

[Clive S]

You can fit a braking resistor if the driver black box has provision for a braking resistor. A braking resistor dissipates unwanted energy and is one of the reasons a body might chose thicker wiring.

Robin Can you please send me some of that shit you are on as it just might help me to understand what the f@*k you a taking about.

[Robin Hewitt]

Robin Can you please send me some of that shit you are on as it just might help me to understand what the f@*k you a taking about.

I keep taking breaks from PCB design. I am trying to wire up a 168MHz processor without resort to 4 board layers and it is not easy getting sufficient decoupling and copper down to get the power everywhere it needs to be. I am having real problems while you lot are having imaginary problems and I guess I am getting a bit jealous.

To quote Jesus, purely because it is hard to argue with Jesus, "You're far too keen on where and how, but not so hot on why"

[Clive S]

To quote Jesus, purely because it is hard to argue with Jesus, "You're far too keen on where and how, but not so hot on why"

Can you point me to the document where HE wrote that please.

[Robin Hewitt]

You don't believe me? Google is your friend

[JAZZCNC]

To quote Jesus, purely because it is hard to argue with Jesus, "You're far too keen on where and how, but not so hot on why"

I wonder WHY all the time.? . . . Often wonder WTF your on about and WHY you say the Shite you do.!! . . . . . Go back to the Stone age because your just confusing new users with BUM info that isn't relative to todays modern components.!! . . . . . Sorry to be so harsh but your going to cost somebody lot of wasted time and possibly money with such Rubbish.

Now that's the last I'm saying so OP can get back on track.

Edward:

You won't get near taxing those drives with Mill this size so don't worry about Over current etc. Just fit and enjoy.!

Regards Earthing then just use Star ground and shielded cable and you won't have any troubles. Size wise then 1mm is fine for motors and limits etc so just buy one size as it's easier and often cheaper as Some suppliers have minimum qty. 4-Core will do both

[Edward]

Brilliant, thanks Dean and everybody, I'll just get on with it.

I think this thread is quite old, but the OP asked questions that I was also interested in.

Edward

[Robin Hewitt]

Calling me names and telling me I am stupid rather than explaining why I am wrong does rather suggest that you do not have a clue what you are talking about. Your appeal to authority, "because it's well documented why shielded cable is required" is a fallacious argument. Where is this document?

[Neale]

I like to understand "why", because that helps me know what and how. Trouble with earthing and screening, though, is that you can still get odd problems because you can't actually see or measure what's happening, particularly with intermittent problems.

Been testing my new machine, checking machine limits. X axis kept tripping around 20mm or so before it reached the limit (proximity) switch, although it wasn't clear which switch had actually tripped. Cables are all screened CY but run in same cable chain - limits in one cable, with motor Y and Z cables, but separated as far as I could by spindle cooling tubes. No other tripping problems, just this one point near the upper end of X travel. However, at this point the unrolling cable chain was next to the cable to X proximity switch (the usual unscreened thin stuff); I re-routed the proximity switch cable and the problem went away. Similarly, my earlier problems with home switch triggering went away when I moved the control box from its test position on floor in front of machine to its installed position bolted to frame with earth connection to star point. Moral of story? Use good earthing practice, screening helps, but be alert for the unexpected just in case.

I'm using 1.0mm CY for my Nema 23/EM806 combination, but buggered if I can work out where to put my braking resistors...