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  #1  
Old Sun 09 January 2011, 09:59
smeagle
Just call me: smeagle
 
Bucharest
Romania
I need too much power ...

for my cnc I will need after my calculation a source oh 60V and 1500 VA I will have 2 stepper for gantry of 8,5 Nm (1200 Oz) , one same motor for Y axis , one 3 Nm (420 Oz) for Z axis , and for the 4th axis maybe a 3 Nm so the 8.5 Nm motors has 6 A and inductance 6.5 mH , the 3 Nm motor has 3 Amps and 3.2 mH , and if I calculate the voltage the resoult is max 80 V and I can use 60 V source (because for the 3Nm motors I need 60 V max) and I have 3x6+2x3 = 24 Amps x 60 V = 1440 lets say 1400 W (I use some profesional drivers) , what I have to do ? use 2 sources in paralel or what do you recomand me ?
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  #2  
Old Sun 09 January 2011, 11:48
bradm
Just call me: Brad #10
 
Somerville(MA)
United States of America
Smeagle, many of the questions you are asking in new threads have already been answered elsewhere in existing threads. For example, the very first thread of this forum section addresses the question of power supply sizing, and why you don't need as large a power supply as you might think. Over in the top of the motors section, there is a sticky thread that addresses why you SHOULD NOT USE those 1200 Oz steppers you are considering.

You may find some more hours of reading will save you much time and effort, especially the sticky threads at the top of each section.
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  #3  
Old Mon 10 January 2011, 18:09
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
It's sometimes hard to jump into a forum that has been in place for several years and know that most of the questions have already been answered. One of the mistakes that people make is that they need a LARGE stepper motor. That is not true. Without a gearbox or belt-drive a 600 oz*in motor is adequate. With a gearbox or belt-drive a 300 oz*in or 450 oz*in motor is adequate. Remember that the MechMate uses V-rollers and those V-rollers greatly reduce friction. Instead of thinking that a 100 pound gantry requires 100 pounds of torque to move it, think instead that with the V-rollers, that 100 pound gantry may only require 10 pounds of torque to move it.

Another mistake that many people make is that they have to use the maximum voltage permissible to drive a stepper motor. That is also not the case. The maximum voltage is meant to drive the stepper motor at full speed. A CNC machine does not require full speed. If the motor can turn at 750 to 1,000 RPM, it will do more than it is expected to do. That speed often requires less than 75% of the maximum voltage.

It takes a little reading and it might require that you email a few of the regular posters, but answers can be found that will save you a lot of work and a lot of unnecessary costs.
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  #4  
Old Tue 11 January 2011, 10:49
smeagle
Just call me: smeagle
 
Bucharest
Romania
Yes I study and I decided to put two 630 Oz each side for the gantry (that means 9 Nm and is absolutly enought) and for the Y axis only one of 630 oz , and for Z axis one of 420 Oz and for the 4 th axis 420 oz , so a source of 48 V and 7-800 W shoud be enough I think .
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  #5  
Old Tue 11 January 2011, 10:53
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
http://www.geckodrive.com/upload/Step_motor_basics.pdf

as long as you have applied the principles of power, voltage and resistance with respect to the document linked above, you should be fine with your choices.

Sean
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  #6  
Old Tue 11 January 2011, 10:53
bradm
Just call me: Brad #10
 
Somerville(MA)
United States of America
Smeagle, that sounds reasonable! Keep up the research!
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  #7  
Old Wed 12 January 2011, 03:17
Robert M
Just call me: Robert
 
Lac-Brome, Qc
Canada
Send a message via Yahoo to Robert M Send a message via Skype™ to Robert M
Mike to the rescue….again !

In the name of many, thanks for still being around and posting your wisdom & guidance!
Robert
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  #8  
Old Wed 12 January 2011, 23:40
Red_boards
Just call me: Red #91
 
Melbourne
Australia
hear hear
And you too, Robert!
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