A "Generator Breaker" was a special breaker used on dual voltage generators.
A generator circuit breaker had nine terminals rather than the common six terminals.
The center three contacts bypassed the overload mechanism of the breaker. The breaker worked on the assumption that each of the two windings carried equal current and monitored the current of one winding only.
The same breaker could be used for either the low voltage connection or for the high voltage connection.
The breakers were typically stud mounted and jumpers on the studs allowed easy conversion between low voltage and high voltage.
I haven't seen a generator breaker for about 15 years and that one was probably new in the 1940s.
The typical application would be for 208/480 Volt generators ranging in size from about 30 KVA to several hundred KVA.
These are older than the internet. You will only find them in old text books.
Bill
-------------------- Ohm's law
Not just a good idea; It's the LAW!
Mlmlzx,
I suppose you are asking about Circuit Breaker for HV Generators.
IEC have adopted existing IEEE standard for Generator Circuit Breakers. See below:
IEEE/IEC 62271-37-013-2015 - IEEE/IEC International Standard for High-voltage switchgear and controlgear -- Part 37-013: Alternating-current generator circuit-breakers
The generator circuit breaker is used to synchronize the generator to the grid and to protect the generator in case of fault occurrence but also to prevent excessive stresses to the power equipment including the generators for long duration due to external short-circuit faults that may damage the generator.
"Generator Breaker" without further explanation opens things up to all sorts of interpretations. At one end of the scale, Bill has your answer. But that's a far cry from a 24kV generator breaker that has a 20kA thermal rating; no not an interrupting rating of 20kA, but a continuous current rating of 20kA. Also a rather specialized device but vastly different. For some ranges of voltage and current some "normal" breakers are suitable for generator applications. It depends.
I’ll see your silver lining and raise you two black clouds. - Protection Operations
