On Monday 27 April 2009, Erik Christiansen wrote: >On Sun, Apr 26, 2009 at 01:23:08PM -0400, Gene Heskett wrote, on another > >thread which I'd rather not hijack: >> That UPS is about to hit the yard sale table, its >> a Belkin, monster sized 1500WA rated, eats its batteries in a year a $225 >> set. >> >> I'll have to go reboot it I suppose. Ok, its attached. The UPS? I had >> to bypass it, toast. > >Gene, > >If the transformer's OK, then you may still have more than a boat >anchor. I've just eviscerated a similar sized UPS, to start to make my >first EMC box. > >The transformer may be able to remain, to provide power to the drives. >There were no batteries to confirm the voltage, but the H-bridge uses >100v IRF3710s, and the electrolytics on the bridge are 80v, so my first >guess is 48v. > IIRC there are 4 6 volt gel cell packs in it, 24 volts. This one is a big old honk and 6 years old at least. I have replaced the batteries and blown the dirt out of the fans & case several times, but it just plain runs too darned hot for gel cells and they expire in about a year, at $225 a set. Screw if, Belkin doesn't admit linux is an OS, and when I do buy next it will be an APC, and this belkin under this desk will goto the shop for that machine. In the meantime the older one is bypassed out in the shop. I'll save the piece I suppose, it could make a psu for the motors, but the present one is narrower, 28 volts (xylotex amps) and bulletproof, I've used it for edm while it was running the motors many hours. Slow, so I built another recently, which can eat through a circular saw blade in 10-15 minutes, nice.
>That should be fine to feed drives for some 300W 24v motors I have. My >beginner's understanding is that so long as the current is limited, and >the motor insulation takes it, modest overvoltage will give better >acceleration without harm. But the xylotex is 30 volts max. >If I had to go to higher voltage motors, voltage doubling would require >twice as many capacitors, but I could use 80v types in the two 48v >halves, which might make them easier to find. Admittedly, there'd only >be half-wave rectification in each leg, so I'd need twice the >capacitance x twice as many capacitors. Don't want to go there. > >Low ESR capacitors [1] are what I have to seriously look for now, after >confirming the transformer voltage. Since there are two primaries I >can't just connect them in series and apply 240v. If I chance to connect >them in antiphase, the circuit breaker would be seriously tested. I'll >feed low voltage AC into the secondary, to measure the turns ratio. > >Your enclosure and transformer might still be able to earn their keep, >too. Too wide, its about 9" wide, 16" deep and 10" high. No room for it on that shelf. And I'm cramped. > >[1] I'll heed your admonition about catastrophic capacitor failure. :-) Its not the caps that fail, its all the other stuff that can't take the surges when the esr on them goes to hell. >Erik > >---------------------------------------------------------------------------- >-- Crystal Reports - New Free Runtime and 30 Day Trial >Check out the new simplified licensign option that enables unlimited >royalty-free distribution of the report engine for externally facing >server and web deployment. >http://p.sf.net/sfu/businessobjects >_______________________________________________ >Emc-users mailing list >[email protected] >https://lists.sourceforge.net/lists/listinfo/emc-users -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Backed up the system lately? ------------------------------------------------------------------------------ Crystal Reports - New Free Runtime and 30 Day Trial Check out the new simplified licensign option that enables unlimited royalty-free distribution of the report engine for externally facing server and web deployment. http://p.sf.net/sfu/businessobjects _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
