Centroid CNC4

BigJohnT wrote:

Some stepper formulas for calculating voltage are here:
wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Stepper_Formulas

Thanks John!

Ohm's Law R x I = E (Resistance x Current = Voltage)

Phase resistance: 0.28 ohms
Phase current bipolar: 10 A

0.28 * 10 = 2.8V

So using the formula above I get 161.28 Vmax. In any case I should be fine.

If I've done the rest of the math correct I think a 20 amp 50 VAC transformer will work. I'm assuming 2/3 of 10 A per stepper. How does the amperage relate to the primary and secondary? I'm assuming I need 20 amps on the secondary? How many amps will the primary draw?

BigJohnT wrote:

You might have to google that one to get close but it will be less amperage but take more power as there are some losses in the transformer. A scientific wild ass guess would be around 10 amps on the primary if your transformer is going to be 120vac to 50vac.

I was thinking along those lines. What about toroidal power transformers?

www.alliedelec.com/Images/Products/Datas...AGNETIC/967-0232.PDF

BigJohnT wrote:

I used this guys power supply when I built my plasma table a few years ago. I like the idea that it has 5vdc and 12vdc also included.

Well... isn't that the slickest thing. First I went to the site and found the transformer for $100... then I discovered they offer hundreds of PS models. I think the PS-15N70R5R12 (70Vdc 11Ax2, 5Vdc 1A, 12Vdc 1A) will work perfect. Price isn't bad considering it's ready to go. I really like being able to pull 12v and 5v right there. That will power the Pico perfectly.
www.antekinc.com/pdf/PS-15N70R.pdf

Thanks for the link!

forhire


I have those pages. Let me know about the quality of these. I had to reduce the quality a bunch to make them fit here. Let me know if you want the original file over personal email or something.

here is page 66

tpwjayson wrote:

here is page 66

I sent you a PM but no need to send higher quality. I corrected the brightness and contrast and it printed perfect! I now have my missing page

Thanks a ton!

Have you made any progress on using your CNC4? Did you get the latest gtkterm?

Awesome, glad I could help. I got the latest version of gtkterm but I have been so busy at work that I haven't been able to try it out yet. I will probably have time tomorrow and will let you know how it goes.

I am still totally up in the air as to where I am going to go with this controller. I really want to hear what you will finally decide on for your upgrade so I know a bit better how to proceed. I can make this one work just fine for a bit but my boss would really like an upgrade.

tpwjayson wrote:

I am still totally up in the air as to where I am going to go with this controller. I really want to hear what you will finally decide on for your upgrade so I know a bit better how to proceed. I can make this one work just fine for a bit but my boss would really like an upgrade.

On a BOSS 1 I'd try to squeeze everything you can out of it before you upgrade. I see BOSS 3+ machines with upgraded controls for around 4k. I found a BOSS 5 near me this week with servos and a mach control (which could be changed to emc2 easily ). This really makes me ponder my upgrade... maybe I'll buy a second cnc mill

Here is my shopping list so far:
1 Power supply www.antekinc.com PS-15N70R5R12 $240
3 Stepper drives www.geckodrives.com G203V $147 each x 3 = $441
1 Universal Stepper Control (USC) pico-systems.com/univstep.html $250

I'm still working on the jog control portion. Does anyone have a recommendation? I'm not sure I want to use a touch screen or mouse.

I am still thinking about the stepper encoders. I believe the USC can read encoders. The USC can also counts pulses... not sure how that compares to encoder counts.

My existing relays won't work so I'll need to buy some solid state ones for the USC.

I ordered new pulleys so I can get better resolution. Can't wait for them to arrive

The more pieces of the puzzle I work out the more clear the project becomes. The cost isn't bad so far even replacing the power supply. I suspect the total will go up a bit more due to enclosure and incidentals. Not sure how long it will take to assemble and debug everything. Honestly the down time is my biggest concern.