power supply current rating?
Quote:
Originally Posted by
CoAMarcus
Mongkol,
Regarding the voltage to feed your drive, this is dependent on the inductance of your motor. Below is the correct and most up to date formula for figuring out the proper supply voltage:
Drive supply voltage = 32 * SQRT(mH inductance)
If your motor is rated at 4mH, then it will be 32 times 2, or 64VDC.
Your motor will be way too high inductance to use with our drives, as the voltage required to push the current through the windings to compensate for iron losses will just be too high.
-Marcus Freimanis
From the statement above am I correct that 3.8mH for 62VDC will be too high as well for this drive? Was going to buy these cheap steppers but after reading this I checked and they are 3.8mH so not useful with the G250. I do have some lower torque steppers which I'll try out first that are 3A, 2.2mH which works out just right at 48VDC.
I discovered this searching for info on the correct current rating for the power supply I need to buy. The only thing that has me confused is the fact that the motor rating is 3A/phase. Does this mean for one motor I need a 6Amp supply (2 phases x 3Amps) or a 3Amp (only one phase firing at a time) power supply?
I've also been thinking about the inductance looking at stepper motor specs and as I suspected, the inductance goes up, current rating is down (more copper windings so this is expected) and visa versa (less windings, lower inductance, higher current). From what I can see this means the ideal maximum torque stepper motor for the G250 is about 200oz-in, maybe a bit more. Motors above this will not run to their full capability due to reduced drive voltage or and current. So if I want to run higher torque steppers at their full capacity I should be looking at the next model up Gecko drive such as the G201, correct? Or am I looking at this the wrong way and the G250 will drive any 3Amp stepper to it's best (I suspect not but I'm not qualified in this area to confirm).
Thanks
Steve