I am servicing a machine that uses a 3 phase power supply. Some of the components (motor, compressor, fan) use 3 phase power. Other components (solenoids) use single phase (phase to phase) tapped from L1 and L3. I understand regular single phase-120v and a nuetral. The nuetral creates the potential for the current to flow. How does the two hots, in this case (L1 and L3) create a potential without using a nuetral wire? If a soleniod is using two hots out of phase, how is that single phase and how does the current flow? How is there a potential created between the two phases? Thanks for any help.