In an alternating current system, a phase refers to one of the individual voltage waveforms or the physical conductor that carries it. In standard three-phase power, there are three distinct phases separated by 120 electrical degrees. Electricians and engineers measure the voltage between these phases or between a single phase and the neutral conductor to verify system balance and correct rotation.
We lost the red phase on the incoming feeder, which is why the induction motors are stalling.
Also heard as
- line
Do not mix it up with
- Neutral conductor: A phase carries the primary driving voltage, while the neutral serves as the return path for unbalanced currents.
Related terms
Polyphase
Describing an electrical system that uses multiple alternating currents with staggered phase angles.
Single-phasing
A destructive fault condition where a three-phase motor loses one of its supply phases.
Neutral conductor
The wire in an alternating current system that provides the return path for load current.