New build with recycled parts on a ridiculous budget 120cm*60cm work area

[Desertboy]

The current limiter thermistor came so hooked it up and turned on the PSU came one OK although need to test it with load of course.

Now need to wire it through the mcb type b then through the resistor and to the transformer and see if it works ok, now we get to see if I got the right one lol was quite confusing which one to get.



Can't do a lot more until the last AM882 comes although getting it to move the dual ballscrew axis would be good, have got the fan holes drilled now.

[Desertboy]

Got the MCB hooked up and the current limit thermistor and it all works perfectly ;)

MCB 6amp type b, trips without the thermistor doesn't trip with it. PSU appears to be running fine have to wait for the AM882 to come so I can test it under load but should be fine. The resistor is rated to 5amp once it's up to temp.

Is there any point adding a slow fuse as well now I have working MCB type b protection?

The 12v PSU doesn't go through the MCB only the toroidal transformer.



This is the correct current limited thermistor for a 1kva toroidal transformer

http://www.ebay.co.uk/itm/2x-NTC-10D...72.m2749.l2649

If anyone else is interested.

I notice when you turn the transformer off the AM882 stay lit for about 5 seconds and when you test the capacitors when you've turned it off they're ready 7v's so it's good to know the capacitors are mostly discharged by the AM882's at switch off although I might still add a resistor.

[Neale]

Is there any point adding a slow fuse as well now I have working MCB type b protection?

I don't think so. The MCB should trip after a sustained overload, i.e. at something like twice the rated current, they should both trip within a minute (roughly). The B curve/C curve thing is about how much of a short-duration overload they can take to cope with switch-on surge and so on. That's not so different from a slow-blow fuse, so the only reason for fitting a fuse as well is in case the MCB doesn't work. How much should you trust safety devices? My machine has a couple of fuses on the PSU (commercial item) and one of those blew once. The PSU was operating well within its rating; it was just that the fuse was tired and didn't want to play any more. I'm not sure that I don't trust the MCB more than the fuse, but I don't have much experience of them in this kind of situation. On the other hand, all your house wiring is probably protected by a bunch of MCBs, so the people who make the rules trust them.

[Desertboy]

Mr Postman arrived with a package from China for me can be only one thing ;)

Won't be back at work till 1pm but shouldn't take long to fit it, test it. Then drill the box and fit grommets for the nema's, limit switches, mains input & spindle output's, fit the box, fit the plate in the box and finally fir the wiring to the board lol. Hoping to get it all done today then tomorrow, get a sheet of mdf for the bed and start configuring the machine. Be nice to get the bed milled flat and vacuum holes drilled over the weekend.

I have a a few things I would like to build out before the end of the year and I'm starting to believe I might just get at least some of them built ;) Not long now.

e2a was my AM882 in the post dropped it on the machine and tested it works fine ;) I know have 4 moving axis and my Y axis is linked up. Took me some head scratching in Linuxcnc and editing the .hal and .ini files probably click a button in Mach 3 lol.

Tomorrow I can get the box finished and start with homing.

[Desertboy]

Long time coming but finally she moves using the AM882's and the Toroidal PSU from linuxcnc ;)

https://www.youtube.com/watch?v=JH7ISQcmeUM

At the moment I auto tuned the steppers (Hopefully, flick the SW4 switch on/off/on with rotation knob in 0 position) and set microstepping to 2 just to get it working but will get it set it properly next couple of days.)

What microstepping do others use for their AM882's? I was thinking X16.

[Neale]

What microstepping do others use for their AM882's? I was thinking X16.

I use x8, with EM806. That's with NEMA23 3Nm, 5mm lead ballscrews, 1-1 pulleys. Seems like a good compromise between smooth running, resolution, and maintaining torque. Gives me about 5000mm/min rapid, which is slower than some people but the max I can manage with my ballscrew length.

[Desertboy]

8X it is ;) do the motors get quieter the more microsteps you have? When I first ran them one of the motors was virtually silent.
https://www.youtube.com/watch?v=O4_u5ov-9cc

Ordered a 720p webcam to set a timelapse up so I can record my mistakes ;)
Did you use the auto tune function on the EM806? Wondering if I did it right, flicked the SW4 switch on/off/on you hear some minor buzzing sound for a second and it's done. Does this sound correct?