Dictionary of Electrical Power Engineering and Automation Systems

• To engage — To establish an electrical connection by closing a circuit using a switch, relay, contactor, or circuit breaker; to put an automated system or apparatus into operation. Broadly, the action describes the automatic or manual triggering of a switching mechanism, being the opposite of the term 'to trip' or 'to uncouple'.
• Self-excited — Regarding machines, generators, or electrical systems: self-excited; producing its own excitation current required to create its magnetic field without an external power source. Broadly or figuratively, it describes a system, circuit, or state that stimulates, maintains, or amplifies itself through its own internal mechanisms or residual reactions.