On Friday 24 January 2020 16:00:06 Brent Loschen wrote: > I currently power a 7i76 from the 5i25/cable, and am wondering if it's > OK to power the Spindle + and - (TB4 pins 1 and 3) using that 5v > source, or if it requires a separate 5v supply? If current draw from > the cable is no problem, are there any other drawbacks to using that > 5v source? (i.e. noise, stability, etc.) And finally, Spindle + and - > pins appear to be isolated from the rest of the card, and it seems > like I should connect Spindle - to 5v neutral regardless of which 5v I > use. Do I have that right? (it will be connected to a VFD with 0-5 > input requirement) > > Thanks, > Brent > No. Those 3 terminals are an isolated electronic resistor intended to replace a manual speed potentiometer controlling a vfd, using the vfd's own 10 volt supply to the + and its ground reference to the -. That generally is totally isolated from the rest of the world in a vfd control world.
This is all explained well in the 7i76 manual. It can also control one of the Pico pwm-servo amps for dc spindle motors, but you need to invert (IIRC) the enable line between the spindle enable out and the pwm-servo amp. And can do that control much faster than a spinx1 as the pwm-servo amp can also be controlled by a dc voltage input. For that, and most of those dc motors, like the one on the G0704, are 90 volt motors rated to use 9.7 amps at 1 hp full load. My dc supply makes 126 volts and can do 20+ amps. With the pwm-servo set for a 17 amp peak, i'm getting considerably more than that 1 horse by the time I hear the current limiter kick in but normal cutting load is under 3 amps. Its been doing that for around 4 years now with no indication of impending trouble. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
