runaway speed of hydrogenerator
runaway speed of hydrogenerator
(OP)
Hi,
I have a question regarding meaning of "runaway speed" requirements specified for hydrogenerator sets. My doubt refers to the duration usually specified together with runaway speed value (eg. 200% of rated speed during 10 min.). I've never seen additional information about limitation of 'runaways' number in certain period of time (or generator life). Does it mean, that all elements of generator have to be designed (with regard to their machanical endurance) in fact for continuous operation at runaway speed? Are there any normative references to this aspect of runaway speed rating of hydro machines?
I have a question regarding meaning of "runaway speed" requirements specified for hydrogenerator sets. My doubt refers to the duration usually specified together with runaway speed value (eg. 200% of rated speed during 10 min.). I've never seen additional information about limitation of 'runaways' number in certain period of time (or generator life). Does it mean, that all elements of generator have to be designed (with regard to their machanical endurance) in fact for continuous operation at runaway speed? Are there any normative references to this aspect of runaway speed rating of hydro machines?





RE: runaway speed of hydrogenerator
RE: runaway speed of hydrogenerator
2. motor is built with a structural integrity such that id does not 'fly apart' due to the centrifugal forces acting on the motor b/c it's spinning
*i'd be more worred about 1! the motor will most likely have to rotate at a phenominal speed to 'fly apart'...
RE: runaway speed of hydrogenerator
In the case of hydro-generators, we may be dealing with a rotating mass of several tons and a diameter of 10, 20 or more feet. The rotation may be around 100 RPM (depending on the number of poles and the freqwuency). The designers must be concerned with centrifugal forces. The self destruction speed may be less than "phenominal".
respectfully
RE: runaway speed of hydrogenerator
RE: runaway speed of hydrogenerator
RE: runaway speed of hydrogenerator
To answer your question, yes, the hydro generators are designed to withstand the stress to runaway speed which varies from 1.7 to 2.1 times depending on the turbine type.
I have seen remnants one 50 MW hydro generator completely wrecked and it was proved the design was inadequate.
The wreckage is still kept outside the power house as a museum piece to show how things fail.