Fingers crossed it'll cut ally

[Jonathan]

I would put a separate fuse on each power supply. Whatever is standard for the computer (3A?), and probably similar for the power supplies. Bear in mind the surge current when you switch it on will be quite high. In my case switching on the stepper motors briefly dims the light in my workshop.


Oops, just realised you're talking about a switch not a fuse Nevermind I'll leave this here.

I'm liking where you've chosen to mount the electrics.

[blackburn mark]

dims the light in my workshop

youve got heafty setup compared with mine

should i also run an earth to my frame, the power supplies are bolted to the frame but iv no idea how conductive the surface of anodised aluminium is ?

[Jonathan]

I thought our drivers were the same? I've got 4 PM752 drivers on a 500VA (I think) toroidal transformer. Maybe it's the big capacitors that cause it...

I think the surface should be conductive enough for an earth. Whether it's a good idea or not I'm not sure. I'd be inclined to say yes.

Good point about the dust. Any fans in there are going to blow in a lot of dust. I found about a 5mm layer of wood dust (and some metal swarf!) in my computer when I cleaned it out on Friday. Probably should have made sure the case side didn't keep falling off, but still...

Edit: didn't see your last post in time :(

[M250cnc]

I'm liking where you've chosen to mount the electrics.

The electrics look nice but really should be as far away from dust as possible.

There are people on the zone that have put the controls in a separate room with air from outside to cool the electrics.

Phil


Sent from my HTC Desire using Tapatalk

[blackburn mark]

as far away from dust as possible.

ill not be cutting wood on this one (acetal/delrin) so i shoulden't suffer the unusual levels of dust that some of you lads have

[blackburn mark]

I thought our drivers were the same?

no, im on a chineese 5 axis TB6560, iv no idea if they will be enough, its a small machine but the gantry weighs almost as much as i do :) .... i think in some parts its over engineerd, i was trying to play it safe, the 20mm plate on the gantry sides are the week link.... i designed it with 200mm x 40mm extrusion but valuframe ran out of stock and couldn't find any

its amazing how much more the gantry sides flex in the Y axis compared with the X axis
ill stick some sort of buttress on them if its a problem

[Jonathan]

I thought the forum had something to stop double posting...oops. That's the problem with having a really slow internet connection.

[Jonathan]

no, im on a chineese 5 axis TB6560...
its amazing how much more the gantry sides flex in the Y axis compared with the X axis
ill stick some sort of buttress on them if its a problem

I'm not thinking today am I, you mentioned the driver only a couple of posts ago, sorry!

Plate is the worst possible cross section for bending in the Y direction. Maybe you could securely bolt some bigish aluminium angle to the plate to make it a bit stronger...ideally get it welded on.
All that aluminium profile must have cost a lot.

I intend to look at the servo controller on Wednesday, or this weekend at the latest.

[blackburn mark]

i was thinking a 20mm arch bolted at 90 down the gantry sides, i need to work out where the torsion might be acting... im pretty sure it wont be a staight line top to bottom

All that aluminium profile must have cost a lot

Owch!! £100 meter, it did hurt spending that much but it is easy stuff to work with and its flat enough not to need machining

I intend to look at the servo controller on Wednesday, or this weekend at the latest.

have you got an ESC for that monster motor yet ?

[Jonathan]

i was thinking a 20mm arch bolted at 90 down the gantry sides, i need to work out where the torsion might be acting... im pretty sure it wont be a staight line top to bottom

Have you had a look at irving's spreadsheet on this? It's interesting comparing the different sections with it.

Owch!! £100 meter, it did hurt spending that much but it is easy stuff to work with and its flat enough not to need machining

Yikes, that's a ridiculous price when you compare it to the material cost.

have you got an ESC for that monster motor yet ?

Not quite. According to the website I need at least 100A and 48v ESC, which is going to cost a lot even from hobbyking! I think a lower current ESC should survive as I'll never need that much power. I'm thinking of replacing the mosfets on a really cheap 100A 24v ESC I have for some much higher voltage ones...that should do the trick for very little money.

Alternatively a friend of mine has randomly acquired a 5.5 KW 400v variable frequency motor inverter from a lift. I think it might be adaptable...