Yes, the inverse relationship I understand. This was not start, but a continuous display (for the limited time it ran) on a 240vac system. There is probably not 25' of wire in the whole run. I have never seen voltage drop to half rating even at 150%. I was just not sure if this is typical with one of these converters or not. The jumping of the pump shaft has me wondering about the start, but just not sure where to point. This was like hitting the on off buttons as fast as you can.. Just a nice puzzle that strains my voltage....
Matthew J. Willis, CET Automatic Fire Sprinklers Norred Fire Systems L.L.C. 318-387-1134 Voice 318-387-1163 Facsimile [email protected] -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Ron Greenman Sent: Wednesday, August 26, 2009 12:08 PM To: [email protected] Subject: Re: 3 from 1 Voltage varies like water pressure and essentially for the same reasons but electrically. Amperage is directly related to voltage as in the formula A=W/V where A=Amps, W=Watts (a unit of work like HP) and V=Voltage. As our friend from Belgium pointed out single phase is not the best way to transfer high power needs but 30-40 amps is in the realm of household gear like water heaters, dryers, stoves, well pumps, etc. I don't think there's any effect on soft start since that's a function of the starter relay and not the incoming raw power. You could compensate for the voltage loss with a giant Variac but I don't know if such an animal is available. When I was young a friend and I got a great deal on some 3 phase woodworking tools and used a big single phase motor to run a small three phase motor as a generator but that was a doctor science experiment by kids with too much creativity and too little sense. On Wed, Aug 26, 2009 at 9:39 AM, Matthew J. Willis<[email protected]> wrote: > I think you are going to be proven correct... > > > Why the drop to 106, 108, 112? Amps were fine 33-38 > > > > > Matthew J. Willis, CET > Automatic Fire Sprinklers > Norred Fire Systems L.L.C. > 318-387-1134 Voice > 318-387-1163 Facsimile > [email protected] > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Todd Williams > Sent: Wednesday, August 26, 2009 11:35 AM > To: [email protected] > Subject: Re: 3 from 1 > > Thanks guys. I didn't look in the commentary. I rejected the idea > because it seemed like it could be more trouble than it is worth. > > > > At 12:26 PM 8/26/2009, you wrote: >>Todd, >> >>20-A.9.2.2 in the 2007 edition. Not prohibited but not recommended. >> >>On Wed, Aug 26, 2009 at 9:12 AM, Todd Williams<[email protected]> wrote: >> > You may need to have an electrical engineer review the installation. >> > I did a single phase pump a few years ago and ran into electrical >> > problems (for which I was blamed). Hired an EE and he went through >> > and found the electrician messed up the installation from the service >> > right through to the pump as well as the generator feed and >> > connection. Didn't have a converter, but did have two transformers >> > because the electrician told us the wrong voltage (208 v. 240 - for >> > which I was also blamed). >> > >> > BTW, what section of the Code says Phase Converters are not allowed? >> > I couldn't find that at the time, but had rejected the idea anyway. >> > >> > >> > >> > >> > At 11:58 AM 8/26/2009, you wrote: >> >>I need some education of Phase Converters. >> >> >> >> >> >> >> >>A 300 gpm Fire Pump (Tank fed), is supplied by one of these things. > Single >> >>phase only is available, so one of these has been installed to >> make it work. >> >>Installed in '06-07ish, just replaced main board in controller. I was > there >> >>to do test following part replace. 240vac, dropped to 106-108 across the > 3 >> >>as indicated on panel. Middle leg showed 422vac in event log, as high > peak. >> >>When started, pump shaft (vertical) jumped up and down repeatedly. We > red >> >>tagged it and are waiting on word from electricians. Pump Motor checked > out >> >>fine. I know they are not allowed, but it was approved, so., I >> just test it. >> >> >> >> >> >> >> >>R/ >> >> >> >>Matt >> >> >> >> >> >> >> >>Matthew J. Willis, CET >> >> >> >>Automatic Fire Sprinklers >> >> >> >>Norred Fire Systems L.L.C. >> >> >> >>318-387-1134 Voice >> >> >> >>318-387-1163 Facsimile >> >> >> >>[email protected] >> >> >> >> >> >> >> >>_______________________________________________ >> >>Sprinklerforum mailing list >> >>[email protected] >> >>http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum >> > >> > Todd G. Williams, PE >> > Fire Protection Design/Consulting >> > Stonington, Connecticut >> > www.fpdc.com >> > 860.535.2080 >> > _______________________________________________ >> > Sprinklerforum mailing list >> > [email protected] >> > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum >> > >> >> >> >>-- >>Ron Greenman >>Instructor >>Fire Protection Engineering >>Bates Technical College >>Tacoma, WA >> >>Member: >>SFPE, ASCET, NFPA, AFSA, NFSA AFAA >>_______________________________________________ >>Sprinklerforum mailing list >>[email protected] >>http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > Todd G. Williams, PE > Fire Protection Design/Consulting > Stonington, Connecticut > www.fpdc.com > 860.535.2080 > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > -- Ron Greenman Instructor Fire Protection Engineering Bates Technical College Tacoma, WA Member: SFPE, ASCET, NFPA, AFSA, NFSA AFAA _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum
