50amp on 120/208 service
I know most systems are setup on 120/240 systems but I need to have a plug installed in a commercial building that has 3 phase lines coming in and power options are 120 and 208. I don't see where tha...
Forum Discussion
CA Traveler wrote:DrewE wrote:Sine waves for sure. But a 240V motor sees that the combined voltage and amps are 120 degrees out of phase with each other. So definitely no longer 240V single phase.
Although the two phases are 120 degrees from each other, the phase to phase waveform still works out to be a sine wave, so it's "normal" single phase power albeit at a lower voltage. There are plenty of single-phase motors that are rated to operate at either 208V or 240V (and likewise plenty that are not so rated).
As long as the motor and it's load is designed for both power sources then all is good. Appreciate the input.
From the motor's point of view, the voltage isn't out of phase at all since it has no neutral connection. It's just a (single-phase) 208V 60Hz AC power supply; the motor behaves precisely as if it were connected to a variac or similar device set to 208V. The current may not--indeed generally will not--be perfectly in phase because the motor is inductive and has a non-unity power factor; but it's not offset from the voltage in any atypical way. (The current waveform in a constant voltage system, such as the modern electrical grid, is of course determined by the characteristics of the load, and not directly dictated by the supply.)
