Gallery, Projects and General > How do I??
Power supply for Nema 23 Stepper ?
John Swift:
a rule of thumb from Geckodrive.com
" The power supply voltage is determined by multiplying the square root of the motor’s inductance by 32, as in the example below for a 2mH rated motor:
32 * (√2) = 45VDC "
the faster you need to step the motor the shorter the time for the motor current has to build up to the current you have set the drive to
the higher the motors inductance the longer it takes for the current to build up
by using a higher supply voltage you can force the motor current to build up to the set value in a shorter time
that's why your going to be disappointed with some of the Chinese cnc kits that have a 24V supply and motors with a very high inductance , about 8 mH or more with some kits
8mH stepper motors will require the driver to be powered by a 90V supply unless you want your machine to run at a snails pace
John
kayzed1:
Thank you John, i just found out why my rotary table runs at around 3 inch per hour :doh:
I need a good stepper motor...
Lyn.
Chuck in E. TN:
Using a higher voltage dc supply on a dc motor by way of a pwm control module is the same as using a higher voltage supply on a stepper by way of a stepper driver. By using PWM, you are not applying the larger voltage constantly, but in pulses. I know it seems to defy logic, do some research.
Google is your friend.
Buell:
--- Quote from: John Swift on November 10, 2018, 12:48:29 PM ---
a rule of thumb from Geckodrive.com
" The power supply voltage is determined by multiplying the square root of the motor’s inductance by 32, as in the example below for a 2mH rated motor:
32 * (√2) = 45VDC "
the faster you need to step the motor the shorter the time for the motor current has to build up to the current you have set the drive to
the higher the motors inductance the longer it takes for the current to build up
by using a higher supply voltage you can force the motor current to build up to the set value in a shorter time
that's why your going to be disappointed with some of the Chinese cnc kits that have a 24V supply and motors with a very high inductance , about 8 mH or more with some kits
8mH stepper motors will require the driver to be powered by a 90V supply unless you want your machine to run at a snails pace
John
--- End quote ---
Thanks for this I have just checked the Inductance on the Box says "Phase Inductance at 1khz typical is 2.5
so If my poor maths is correct that is 46.16v
With that in Mind ...I just need a Medium speed to traverse quickly when Not cutting and a Very slow speed for when it is cutting. Does that alter anything ?
Also just noticed the driver I bought of Fleecebay is rated at Dc 9-40vdc at max 3.5amps and 4.0 at Pk Current which i guess is at Peak current ?
Please excuse my ignorance within electronics as I know Very little and am trying my hardest to grasp a small slither of what many folk know lots.
Buell:
Clearly I shouldn't Go over 40vdc at 4amps as thats all the Driver could handle ?
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