Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: dgalaxy on November 20, 2006, 10:07:10 AM

Title: tuning steppers in mach 3
Post by: dgalaxy on November 20, 2006, 10:07:10 AM
if i have a gecks g201 and 270 oz rex step steppers and 24v 4.5 amp   im trying to get in the ball park is 500 and 40 way off or am i creeping to the sweet zone i just see on here some guys with xylotec boards  have accel around 16  just wondering if im way off or not
does lower accel give you more torque

John
st.louis,mo
Title: Re: tuning steppers in mach 3
Post by: Chaoticone on November 20, 2006, 03:16:41 PM
Hey John,
    Lower accel will not give you more torque. The accel will help you keep from loosing steps. It is just like you pushing a car and pushing a bike. You can probably push them both at the same speed. It will just take you longer to get the car from stop to max than it would the bike. You will just have to play with motor tuning to find what your machine will do. Uping your Voltage to the motors will give you more torque.
Title: Re: tuning steppers in mach 3
Post by: Yodawill2000 on November 20, 2006, 03:39:51 PM
BIG yes on upping the voltage.
I went from 17 to 24 and it made a HUGE differance.
Title: Re: tuning steppers in mach 3
Post by: dgalaxy on November 20, 2006, 04:16:03 PM
so  an accel of 40 or 50 isnt unheard of  on 270 oz steppers i just need to up the voltage is this correct
do you think if i try between 36 and 42 that wont be to much

John
Title: Re: tuning steppers in mach 3
Post by: Yodawill2000 on November 20, 2006, 04:18:23 PM
First we need to know the voltage rating thats on your stepper motor.
Title: Re: tuning steppers in mach 3
Post by: Chaoticone on November 20, 2006, 04:19:37 PM
Do you have any spec sheets, info on your steppers? Running 75-80V on a stepper is common.

The 201s are rated at 80V max.
Title: Re: tuning steppers in mach 3
Post by: dgalaxy on November 20, 2006, 05:35:56 PM
right now im running  3 of them at 24v 4.5 amp power supply



Operation
 Holding torque-Nm (oz/in) +/- 10%  262
 Rated voltage 3.2
 Rated current per phase (amps DC) 2.8
 Resistance (Ohms) +/- 10% 1.13
 Induction (mH) +/- 20% typical 3.6
 Motor length (mm) 76
 Rotor inertia (g-cm^2) 480
 Weight (kg) 0.92
 

 


 
 
Title: Re: tuning steppers in mach 3
Post by: Chaoticone on November 20, 2006, 06:58:16 PM
65-80 volts would be nice. Check out this link. ;D

http://www.campbelldesigns.com/files/power-supply-part-1.pdf
Title: Re: tuning steppers in mach 3
Post by: dgalaxy on November 20, 2006, 08:43:25 PM
you know i seen that 3.62 rated volts on the homeshop cnc web site but i could swear when i bought them it was 1.62  man that just seems like alot of volts for those little nema 23  i got a 48 volt power supply downstairs that came out of a centroid controller maybe ill try that before i sink some money on a new transformer  thanks for the help  ill let ya know what happens

John
st.louis,mo
Title: Re: tuning steppers in mach 3
Post by: Chaoticone on November 20, 2006, 08:54:11 PM
John,
    Steppers like it hot. They are designed for heat. The 48 will be twice as nice. You may not want more than that. I would want at least 75. ;D The only reason I wouldn't go 90  :o is because of the rating on the geckos.
Title: Re: tuning steppers in mach 3
Post by: dgalaxy on November 22, 2006, 07:10:26 PM
hey Chaoticone  i was sitting here tearing into my box i was going to put that other power supply the 48 volt  56000 capacitor one out of the centroid controller in my plasma box i was wondering do you guys think it would matter if it is like a 900va  or it really wont make a difference
my motors are only going to pull 5 amps all together this supply is set up for 9 amps on each motor LOL just making sure im not going to fry anything

John
Title: Re: tuning steppers in mach 3
Post by: Chaoticone on November 22, 2006, 07:26:29 PM
If your PS is rated higher than you will be pulling (AMPS, NOT VOLTS)that is a good thing. More room to add more stuff.  ;D  You would not want your motors to pull more than your drive is rated for. Think of the KV size as the size of the gas tank. You never want to run dry.
Title: Re: tuning steppers in mach 3
Post by: dgalaxy on November 26, 2006, 01:02:17 PM
everything seems to be running pretty smooth  , i wonder if i will lose less steps also i wonder how long my 24v fan will last at forty eight volts ?

thank you so much for your help

John
Title: Re: tuning steppers in mach 3
Post by: Hood on November 26, 2006, 01:11:18 PM
I think if you put a resistor in line with your fan it  should make it last.
Hood
Title: Re: tuning steppers in mach 3
Post by: Yodawill2000 on November 27, 2006, 05:24:57 PM
Or get a 48V fan   ;D
Title: Re: tuning steppers in mach 3
Post by: chad on November 27, 2006, 07:27:04 PM
Or get another 24 vdc fan and wire the two in series ;)

Chad
Title: Re: tuning steppers in mach 3
Post by: dgalaxy on December 04, 2006, 10:40:57 AM
WOW what a difference i can really tell now its been a few days.  i have went to 48v and never looked back
thank you guys so much
John
Title: Re: tuning steppers in mach 3
Post by: Chaoticone on December 04, 2006, 11:17:10 AM
Your welcome John,
   Glad you got going. Post some pics. of your cuts on the design exchange. ;D
Out of curiosity, what accel. are you having luck with now?
Title: Re: tuning steppers in mach 3
Post by: dgalaxy on December 04, 2006, 11:24:25 AM
im running 30 and 500 maybe still a little slow compared to others but im happy. is  30 fast or is it slow do you think maybe i should turn it up a notch
Title: Re: tuning steppers in mach 3
Post by: Chaoticone on December 04, 2006, 11:50:17 AM
It all depends. I do everything from thick tool steel with a 3/4" end mill to v carving acrylic .013" deep. Because of the heavy tool loads I run a much lower accel than I could get away with on the light stuff. Hey, I just thought of something indirectly related to something myself and another member have talked about, different profiles. This guy is sharp. I won't mention his name but his initials are Hood. ;D One for light and one for heavy tool loads. I would go as high as I could without skipping steps. The higher the accel. the better, or easier tuning in your cv mode would be. I think. I think I remember reading somewhere, keep bumping up until you just start to loose steps and back off 10%.