-------- In message <57441aca.8070...@arcor.de>, Gerhard Hoffmann writes: >Am 23.05.2016 um 05:15 schrieb Jim Palfreyman: >> As far as a remedy goes we are going to try a solid state relay that only >> switches on at 0V in the AC waveform. This should slow the inrush current, >> and hopefully the magnetic impulse. >> >> >In the context of transformers and motors, switching on at 0V is >actually the worst point in time.
Well... The motor is almost certainly an "Squirrel-cage" induction motor and that means it is three phase, although one of the phases is probably created with a "starting capacitor". So which of the three phases is going to be the lucky one that switches at maximum voltage, or are you going to switch the phases on sequentially ? A 4kW Variable Frequency Drive costs less than $1k and allows you to control *both* the voltage/time and the frequency/time *both* during startup and during rundown. I wouldn't bother fuzzing around with hacks - I'd just go for the known-to-work solution. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
