I can't find my drawings atm, so I'm recreating them from scratch and will post them as soon as done. Just wanted to let you know I did not forget although sometimes I do.
John John Crane wrote: > Thanks, > > John R. Crane > > On Mon, Mar 21, 2011 at 7:27 AM, John Thornton<bjt...@gmail.com> wrote: > > >> John, >> >> I'll dig out my schematic and make sure it is up to date and figure a >> way to post it to the list. >> >> John >> >> John Crane wrote: >> >>> John, >>> >>> I would like to know more about the way you have engineered your phase >>> converters. I am in the process of adding this capability in my shop. >>> >>> Thanks, >>> >>> John R. Crane >>> >>> On Thu, Mar 17, 2011 at 5:53 AM, John Thornton<bjt...@gmail.com> wrote: >>> >>> >>> >>>> I have three rotary phase converters. The are all using a potential >>>> relay for the start caps and a relay that pulls in the mains. So I don't >>>> have to hold the push button and if the power drops out for a few >>>> seconds the phase converter does not try and restart without the start >>>> caps. I've not had the fun of blowing anything up when building them. >>>> They are all balanced phase to phase within a couple of volts. However >>>> phase to phase the run caps are very different in order to get the >>>> voltage phase to phase to balance. I can post some details if anyone is >>>> interested... >>>> >>>> John >>>> >>>> Dave wrote: >>>> >>>> >>>>> Back when I put my 10 hp phase converter together, I found some charts >>>>> on the web someplace about suggested capacitor sizing. I found a >>>>> >> cheap >> >>>>> supply of capacitors at Mendelson's in Dayton, Ohio >>>>> and bought a small box of them. I ended up using I believe, 4 - 330 >>>>> >> uf >> >>>>> 330 volt units as starting caps and 4- 135 uf run caps. I use a push >>>>> button to start the motor and as long as I hold the button >>>>> down the starting caps are wired into the circuit. When the motor >>>>> >> spins >> >>>>> up I release the button. I tried to use a voltage sensitive relay, >>>>> like the ones used on refrigeration systems and AC systems, but >>>>> it was not reliable probably due to the high current from the large >>>>> number of caps. There is also a motor contactor that seals itself in >>>>> via the button push. That way if the line power drops, the contactor >>>>> drops out and the converter idler motor and he >>>>> attached slave motors are powered down. >>>>> >>>>> The math relating to how this works gets even more complicated when you >>>>> consider the effects of hooking a 3 phase motor that you are going to >>>>> start (a slave motor) across the the idling phase converter motor. >>>>> For a brief period of time, the idler motor becomes a generator. The >>>>> rotor slows slightly and the energy in the rotor pumps power into the >>>>> three phases and spins up >>>>> the slaved motor. It works very well. >>>>> >>>>> During experimentation, it is very obvious when more starting >>>>> >> capacitors >> >>>>> are required as the motor will simply not spin up. >>>>> Adding more run caps helps balance the phases but they never really >>>>> fully balance. >>>>> >>>>> Safety glasses are very good idea when experimenting. Starting caps >>>>> go off like firecrackers if you overstress them. They are only >>>>> designed to be switched in for a few seconds. >>>>> >>>>> A source of cheap starting caps is a really good idea if you want to do >>>>> some phase converter experimentation. I blew up several of them. >>>>> >>>>> Dave >>>>> >>>>> On 3/14/2011 9:01 PM, Jon Elson wrote: >>>>> >>>>> >>>>> >>>>>> >>>>>> >>>>>>> On 14 March 2011 10:50, John Thornton<bjt...@gmail.com> wrote: >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>>> Is it not amazing that the hillbillies from backwoods Missouri with >>>>>>>> >> a >> >>>>>>>> 3rd grade education can make a rotary phase converter without all >>>>>>>> >> the >> >>>>>>>> math... >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>> >>>>>>> >>>>>> Of course! The trick is the windings in the motor do all the math for >>>>>> you, all you need to do is hook up the wires. >>>>>> >>>>>> Jon >>>>>> >>>>>> >>>>>> >>>>>> >>>> >> ------------------------------------------------------------------------------ >> >>>> >>>>>> Colocation vs. Managed Hosting >>>>>> A question and answer guide to determining the best fit >>>>>> for your organization - today and in the future. >>>>>> http://p.sf.net/sfu/internap-sfd2d >>>>>> _______________________________________________ >>>>>> Emc-users mailing list >>>>>> Emc-users@lists.sourceforge.net >>>>>> https://lists.sourceforge.net/lists/listinfo/emc-users >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>> >> ------------------------------------------------------------------------------ >> >>>> >>>>> Colocation vs. Managed Hosting >>>>> A question and answer guide to determining the best fit >>>>> for your organization - today and in the future. >>>>> http://p.sf.net/sfu/internap-sfd2d >>>>> _______________________________________________ >>>>> Emc-users mailing list >>>>> Emc-users@lists.sourceforge.net >>>>> https://lists.sourceforge.net/lists/listinfo/emc-users >>>>> >>>>> >>>>> >>>> >>>> >> ------------------------------------------------------------------------------ >> >>>> Colocation vs. Managed Hosting >>>> A question and answer guide to determining the best fit >>>> for your organization - today and in the future. >>>> http://p.sf.net/sfu/internap-sfd2d >>>> _______________________________________________ >>>> Emc-users mailing list >>>> Emc-users@lists.sourceforge.net >>>> https://lists.sourceforge.net/lists/listinfo/emc-users >>>> >>>> >>>> >>> >> ------------------------------------------------------------------------------ >> >>> Colocation vs. Managed Hosting >>> A question and answer guide to determining the best fit >>> for your organization - today and in the future. >>> http://p.sf.net/sfu/internap-sfd2d >>> _______________________________________________ >>> Emc-users mailing list >>> Emc-users@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/emc-users >>> >>> >> >> ------------------------------------------------------------------------------ >> Colocation vs. Managed Hosting >> A question and answer guide to determining the best fit >> for your organization - today and in the future. >> http://p.sf.net/sfu/internap-sfd2d >> _______________________________________________ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users >> >> > ------------------------------------------------------------------------------ > Enable your software for Intel(R) Active Management Technology to meet the > growing manageability and security demands of your customers. Businesses > are taking advantage of Intel(R) vPro (TM) technology - will your software > be a part of the solution? Download the Intel(R) Manageability Checker > today! http://p.sf.net/sfu/intel-dev2devmar > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ Enable your software for Intel(R) Active Management Technology to meet the growing manageability and security demands of your customers. Businesses are taking advantage of Intel(R) vPro (TM) technology - will your software be a part of the solution? Download the Intel(R) Manageability Checker today! http://p.sf.net/sfu/intel-dev2devmar _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
