A 7400N cannot source much current, maybe 1mA. It can sink up to about 16-20mA. The way the schematic is drawn, the pin 11 driving LED2 will always be drawn low by LED2, as that pin cannot source enough current to drive the LED. Thus, it seems pin 11 will always be low (less than 0.8V??)
This circuit, even if it worked, would be toggling at 60Hz (or faster) since it seems to be simply comparing the 3 phases of a 3 phase 60Hz signal. Also missing in your schematic is the +5V supply for the 7400 IC. Where does that come from, the +12V supply?