> On Friday 21 February 2020 11:53:16 Nicklas Karlsson wrote: > > > > Greetings all; > > > > > > I have added a 40 amp SSR in the relay box with the two that are > > > sequencing the spindle's psu startup for a soft start, but its not > > > intentionally connected to those 2 other than as a power src when > > > its enabled. Except this one is to be enabled by the E-stop.out > > > signal when its on, f1 pushed once after start. The idea is to turn > > > on motor power etc to the remainder of the system with the F1 key. > > > > Be aware that failure mode of SSR I am pretty sure is short ciruit so > > that it does not turn off. Expect SSR is implemented with a thyristor > > or mayb triac and they will not turn off a load with low power factor. > > Even though it is very likely to work most of the time I would not > > fully trust a F1 button for emergency stop. > > I'm aware of that, but so far I have had zero failures with the hoymk > brand of 40 amp 450 volt SSR's from mpja.com since using 2 of them to > soft-start the spindle motor psu for about 3 or 4 years now. 2 of them > are controlling all motor power including a 1.5 horse vfd from a pi > running the sheldon. So when lcnc isn't running, the Sheldon draws less > that 10 watts, and its monitor draws 11 watts.
I beleive you and it will probably not fail while changing tool. Table end stops in CNC machine are rather nice, not much will happen unless you ar inside machine which is rahter unlikely compared to end stop on road or maybe thru roof for some kind of lifting device both there you are inside vehicle, fail once in 10-20 years and killing rate might be rather high. _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
