my slow 12v system

[chronon1]

gives about 10-11 IPM speed .

It has a standard 12V pc power supply adn some big fat resistors that can disapate alot of watts.
the motors are step syn 3.5V 1.5 A rating.

I asked the maker about speeding it up .. it would be a b.... to put bigger screws in as the nuts are glued into the MDF trucks ...

so if we doubled the voltage of the power supply and double the resistance,
this was supposed to about double my speed .

Is that all there is to it ? will my motors handle it ?

Thx.

[pminmo]

how many wires are the motor? what kind of motor controller?
and yes increasing the ps will help. why stop at 24 if your controller will handle more. Top speed practicle speed would be around 38V if your controller will handle.

[chronon1]

These are unipolar, 6 wire . i dont know what kind of controller i could find out...

so if i double the voltage and the resistor resistances, i would get hte 20 ipm without losing steps ?

i'll ask the builder also ... but essentially thats what he said ...

[dertsap]

power-one F12-12A (model) come up on ebay quite a lot , they are a pretty high end supply that can run 24v at 12a or 28v at 10a ,
i have two in series for 56v , they are great supplies

http://cgi.ebay.com/6-8-ohm-220-watt...QQcmdZViewItem

these guys are who i bought resistors from for my other board that i was running at 24v , they are cheap and ship quick if these resistors won t do then leave him a meassage and ask what he has for you

if your a patient man you will find one of the power-one supplies on ebay they come up every coupla weeks ,and i doubt you will be disappointed with it

[dertsap]

also you may want to concider changing your lead screw , ive been using 3/4-6 acme screw and it work great

[chronon1]

Thanks Derstap... I have some bipolar motors and drivers for an x and y axis but not yet the Z .. The bipolars (4 wire) don't require big power disappating resistors and give more ounce inches per motor mass.. but I would have to get my own space for that as I cant't further impose on my current situation in doing a build like that , so i guess it would be beefing up what i have currently .

My current machine has the gas pipe roller bearing X and Y but the Z is only a rod and bronze ring friction surface, and that screw is only 1/4-20.

I was thinking the 1/2 "-13 tpi screw could be good but i would have to unepoxy the nuts out of the trucks on the X and Y and that could lead to further issues with the machine being out of wack from having to destroy the mdf -epoxy bond. I bought this machine on the cheap so that I could learn g-code and the whole method of cutting and Cad-Camming and bits and paths etc. ... So .. I am still well into my learning curve .. table is about 12x17 and z is about 2.5 . Does anybody know what chemical disolves epoxy ? ... acetone ?

[ger21]

Originally Posted by chronon1 Does anybody know what chemical disolves epoxy ? ... acetone ?

heat

[dertsap]

i started out 1/2-13 then to 3/4-6 acme which was the best choice for me , i was running it with 120oz motors and it worked well , spider couplers are cheap and you can change over to larger or smaller motors easily without interupting your system

[chronon1]

the physical amass of 3/4 rod is large - that much weight seems too much.. It seems like it's 'too big' for my system -- my motors are probably 1/4 to 1/3 the torque of yours. They are about 2.25" diam. and about 2" height (including mounting plate)

[dertsap]

Originally Posted by chronon1 the physical amass of 3/4 rod is large - that much weight seems too much.. It seems like it's 'too big' for my system -- my motors are probably 1/4 to 1/3 the torque of yours. They are about 2.25" diam. and about 2" height (including mounting plate)

you d be surprised ,thats what i had worried about ! , the motors that i previously had connected were 120oz nema 23 and they turned it no problem , the weight is supported by pillow blocks and the screw spins pretty freely by hand when everything is powered off

[Jason Marsha]

Before you make any major changes try to get 24v - 30v as suggested before. The increase in voltage will move your steppers a lot faster and this increase may help you avoid altering the original setup at this time.

Jason

[chronon1]

I had taken it apart in May and took a pic -- I think it is kind of custom but looks like 3 chips and 4 transistors per axis , a standard uni driver design. There are , I beleive, 3 lg. 5ohm balast resistors ( 1 for each axis) - the builder oversized wattage to allow for long life. The other part not in the picture is just the PC powersupply.

So essentially, If I get 3 fat 10 ohm resistors, and replace the 12V PC with a 24V supply(with sufficient current), I should be able to double my speed from 10 tpi to 20 tpi without losing steps ... ?