On Thu, 2012-05-24 at 10:05 -0500, John Thornton wrote: > I've built several rotary phase converters using plans from the web but > they all seem to stop at adding a few caps to balance the voltage and > the auto start circuit with the potential relay. > > Have you ever peeked into your commercial unit to see what else is there? > > John
I looked at several sites on home built rotary converters when I built mine. A couple of sites had some tuning information, which if I recall correctly, sized the run capacitors for an expected load. I would think an Aurdino like processor could measure the voltage and current on each phase and switch capacitors in or out as needed. It may be that a the load range could be wide enough for a normal fixed capacitor rotary converter to work fine. My take on flywheels on generators, motor-generators and rotary converters is that energy can be stored in the flywheel and quickly released as the load changes, keeping the output frequency more stable and react to a load change more quickly. Also an induction motor can be made to work as a generator if a circuit is used that can set up an initial field in the rotor. This might save having to buy an alternator if a motor is at hand. It is also my understanding that a rotary converter always has correct voltage wave phase timing. The single phase input drives one phase of the motor and one phase of output. The other two output phases come from the the other two motor phases as the motor coasts and acts like a generator. It seems to me the motor's coil geometry determines the phase timing in this situation. A VFD might be another solution. Just keep it at 60Hz, but make sure the VFD switches the power to the load, and make sure there are no switched loads on the output. Off hand, the single phase to DC supply has my vote because it seems to have the shortest distance, component count wise, between the power you have and the power you eventually need, but I think we know where the Devil is. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
