On 07.06.25 19:51, Chris Albertson wrote: > Is the tension on a slipping belt higher than just before it slips? It > might be less
> After all, the slipping belt has stopped transmitting torque. This is the > real question > I’ve never measured. There is: Static friction: Friction without slip. Limiting friction: Friction just prior to slip - the highest you'll see. Dynamic friction: After slip - measurably lower. At least that's what was taught in Tribology around 55 years ago, and the experiments we conducted in class confirmed, if memory serves. > A really cheap solution is to put a low-amp fuse on the motor. Not a breaker, > a fuse and keep them in a locked cabinet. People will soon learn to take it > easy. That would have to be slow-blow, or it'd blow on start-up unless you add a soft-start unit as well. I've bought a couple for A$35 ea, about USD30. Google "SSR 100WA R1 4 kw" for a somewhat beefy one. It's good for 2 kW on 110v, 4 kW on 220v, 8 kW on 380v, and can be set for up to a 30 second ramp-up, if desired. There may be bigger beasts, but these were enough for me. From Ali Baba, they turned up pronto. The unit also has a connector with bridging plug. Add a separate overcurrent sensor with relay output, and it ought to be able to inhibit the SSR instead of blowing a fuse. But even if that set-up latches, it's too easy to reset to be sufficiently educational for neanderthals, I suspect. A several-day turn-around for a fix might be better. My SSR is going on a ¾ ton lathe which trips the 20A 230v breaker about 10% of the time, so maybe only when I hit the AC waveform peak on switch-on. Although off-grid, my nominally 24 kW of inverters can probably do 40 kW long enough to make smoke. Erik _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
