My phase converter is wired very close to this diagram. http://www.metalwebnews.com/howto/ph-conv/fig1.html
I've made two of them using surplus 10hp 3 phase motors. For a while I could buy surplus 10hp motors that were new for about $200. That was about 14 years ago. I made one for my Dad that is wired like the one in the picture. As long as you hold down the start button, the additional starting caps are in the circuit. When you release the button the starting caps fall out. Those are needed just to get it spinning. Mine is a little more basic.. I throw the disconnect on and hold down a button which switches in the starting caps. Same idea, different manner to start the converter motor. The caps are adjusted to optimize phase currents in load motors. I've used this converter to supply power to a 3 phase transformer to increase the voltage to 480 volts - 3 phase to test drives. After the power is passed through a transformer, the currents and voltages are very well balanced. I used to use real starting caps but if you holld the button down too long the caps blow with a bang. So I now use regular power caps for everything. A timer could be used to switch out the starting caps also.. But it doesn't take much skill to start up the converter via a button. The biggest motor I have run off this converter is a 10hp motor on an air compressor. That was no problem but I turned down the max pressure from 175 psi to 150psi to minimize motor heating due to the unbalance in the motor currents. I often run a 5 hp lathe off the converter. Dave On 7/31/2014 3:55 AM, andy pugh wrote: > On 30 July 2014 23:04, Dave Cole <[email protected]> wrote: >> Phase converters are pretty easy to make if you have a spare 3 phase >> motor. > I made a partially succesful one once that also stepped-up the > voltage. Neutral between star-point and a phase, and then the three > phases from the phase ends. It needed a 1/4 hp single-phase (or a > rope) to spin it up, but once it was spinning it continued to spin. > > It wasn't a particularly well balanced 3-phase. > ------------------------------------------------------------------------------ Infragistics Professional Build stunning WinForms apps today! Reboot your WinForms applications with our WinForms controls. Build a bridge from your legacy apps to the future. http://pubads.g.doubleclick.net/gampad/clk?id=153845071&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
