Comments sought on new build: A CNC Router for RC Gliders and Planes

**GeorgeD** · 15-08-2010

Where did you obtain the power supply from at that price? HongKong?

**njhussey** · 15-08-2010

Originally Posted by GeorgeD

Where did you obtain the power supply from at that price? HongKong?

How did you guess??

Yep good old eBay...http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=180406610821

I must admit that after reading lots about the cheap Chinese rubbish around on other forums I was a bit hesitant but it has worked well the 4 or 5 times I've powered the controller and stepper up to test so far...As long as it gets me into the CNC hobby and lasts a little while I'll be happy. Got a list coming together for my second one already with much better kit on it...

**mudscience** · 04-09-2010

Hi.

Newbie here.

Thanks for posting this thread as I too am working on collecting bits for my first build, which is to be for PCB issolation milling in the main, but would like to dabble in other stuff.

I am also working to a budget and looking to 'recycle' stuff where I can. Have just bought the same motors and have spent several days checking out the threads on the same driver board and PSU that you have gone for. Will be really interested to see how yours holds up.

Thanks again for the thread and good luck.

**njhussey** · 06-09-2010

Hi mudscience,

I've come to a bit of a stop at the moment due to various reasons. Hope to be able to kick start it again next week or so when things get back to normal, will keep posting any advances!!

**mudscience** · 06-09-2010

Thanks for the heads up. I know you said in your original post that you were looking for comments, but I wonder if I could ask a question to help me on my quest ... you've calculated that the motors will pull 4.5A. Depending on where I look I get different advise on what the 'guesstimate' total current will be. Some indicate # motors x A x 2, which in our case with the C355-P6V's will be 3 x 1.5 x 2 = 9A or # motors x A +2A = 6.5A. Any which way I think your covered, but I was wondering what 'rule of thumb' to use, because my next acquisition will be a PSU.

**njhussey** · 07-09-2010

Well I used the first one you mentioned, i.e. double the total amps for the 3 motors. I'm sure someone like Irving2008 will be able to tell you far more accurately! :)

**Jonathan** · 07-09-2010

Originally Posted by njhussey

Well I used the first one you mentioned, i.e. double the total amps for the 3 motors. I'm sure someone like Irving2008 will be able to tell you far more accurately! :)

I think to an extent it's the more the merrier!
For my 3N.m motors it's 4.2A in bipolar parallel. [bold]You need 66% of the total peak current.[/bold] So three motors, that's 4.2*3*0.66=8.3A. I used a 500VA toroidal transformer, so 10amps. The motors did work perfectly well with a 325VA toroid but I couldn't get quite as high feedrates. I think because the internal resistance of the power supply was too high.

So anyway with your motors in bipolar series it's 3*1.5*0.66=3A. Or in bipolar parallel twice that, but I don't think your driver board will cope with parallel.

**njhussey** · 18-10-2010

Well after about 6 weeks of doing other things (scratch building a RC glider DIY etc...) I spent a couple of hours in the works on Sunday cutting up some steel for the frame and the rails, see attached pics. Just got to cut some angle for the rail supports and do some welding and things will be progressing...think it's gonna take a bit longer than I thought given the limited time I've got to put into it.

Still like British Rail....(as was!) I'm getting there