my build from the start

[h4ppy-chris]

nothing atm irving i think my 1st thing i will do is convert my milling mc to cnc :)

[irving2008]

oh right, just those are very lightweight motors and I was wondering about your expectations of them...

[FatFreddie]

I hope not... 85degC absolute case temp is the maximum recommended temp you should run a stepper at - higher than that and you risk internal breakdown and demagnetisation.... remember inside its going to be a lot hotter!

an 85degC case is too hot to touch for most people. Maplin do a cheap £19 multimeter with a temp probe thats a useful bit of kit for playing with electrics...

Sorry, yes - 130 degrees max internal which is about 85 degrees on the case. This website seems to think 70-80 degrees is normal - bit of a useless temperature that - hot enough to want to avoid touching but not hot enough to make tea.

80 degrees above ambient is pretty tepid in my garage at the moment so I don't think it will be a problem for a while :-)

[h4ppy-chris]

well i tested the temperature 54c

my 24v supply turned up
when its all running should it sound like 56k modem?
can any one recommend a program to start with for gcode.

[Jonathan]

Sorry, yes - 130 degrees max internal which is about 85 degrees on the case. This website seems to think 70-80 degrees is normal - bit of a useless temperature that - hot enough to want to avoid touching but not hot enough to make tea.

Hot enough if you're 6700m above sea level!

My motors (3nm size 23, 4.2A on 75v) rarely got hot. The vast majority of the time I can barely feel any temperature rise. It's only when the machine has been running for a long time that they start to get hot. I think the drivers reducing the current to 50% when stationary helps here.
It makes me wonder if I can up the current a bit and get a bit more torque/speed. It's on 4.09A, could try 4.64A. That'd be up to 30% more heat I think (I^2*R), or 20% above rated power.

[Jonathan]

when its all running should it sound like 56k modem?

Yes, mine does too. Could get it to play a tune if you tried...know the frequency from the step rate. Got three 'instruments' (motors) so could even do some interesting harmony...

[M250cnc]

Could get it to play a tune if you tried...know the frequency from the step rate. Got three 'instruments' (motors) so could even do some interesting harmony...

There have been some Christmas tunes on the zone in the past.

Phil


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[h4ppy-chris]

what motors should i be looking for? the board i bought is the 2.5amp and 24v PSU.

[Jonathan]

what motors should i be looking for? the board i bought is the 2.5amp and 24v PSU.

Depends greatly on the size of your machine, are you using ballscrews/ACME etc. With only 24v you want a motor with very low inductance to get any reasonable speed.
reccomended v=32*L^0.5, so rearranging that:
L=(24/32)^2=0.56mH
So your looking for a motor with an inductance ideally lower than 0.56mH, and sufficient torque...you'll be lucky to meet those criteria so just find as close as possible.

Hope that helps...

[h4ppy-chris]

sort of helps, from this which would you say is the best to go for?