Gas Turbine Engines
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Barit1, I've just read your post again, and I quote: "........governors, one on each shaft, and either one may "take charge" to keep things within limits."
I think I misunderstood your terminology, I know them as 'speed probes', not governors so apologies for my misinterpretation.
There's also the mechanical TOS (Turbine Overspeed) system which is a cable and centrifugal pawl device that cuts the fuel supply in the event of a shaft failure or excessive overspeed.
I think I misunderstood your terminology, I know them as 'speed probes', not governors so apologies for my misinterpretation.
There's also the mechanical TOS (Turbine Overspeed) system which is a cable and centrifugal pawl device that cuts the fuel supply in the event of a shaft failure or excessive overspeed.
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I've always heard electronic speed management referred to as "electronic governing", working off speed sensors ('speed probes') which are merely frequency sensing devices. The logic is all within the FADEC box, which compares actual rpm (via the probes) to desired rpm (throttle position, limited by speed and acceleration schedules). It then makes a correction to fuel flow.
This meets the very definition of a governor.
I have seen a similar system on a shipboard or land-based turbine engine, but never an aircraft gas turbine. Thanks for the enlightenment.
This meets the very definition of a governor.
There's also the mechanical TOS (Turbine Overspeed) system which is a cable and centrifugal pawl device that cuts the fuel supply in the event of a shaft failure or excessive overspeed.
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There's also the mechanical TOS (Turbine Overspeed) system which is a cable and centrifugal pawl device that cuts the fuel supply in the event of a shaft failure or excessive overspeed
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There was quite a bit of discussion regarding regulation of turbofan/turbojet shaft speeds. However a major consideration with turboshaft engines is regulating torque in the output/power turbine shaft. Most turboshaft engines can easily produce greater levels of torque in the output/power turbine shaft than it can safely handle.
The problem of shaft torque capacity can be quite significant in high power engines that have a forward PTO and the power turbine located aft. The PT shaft of these engines ends up having a modest diameter and long length. Many turboshaft engines (like the PT6) locate the PTO at the turbine outlet to avoid this problem.
Older turboshaft engine torquemeters often measured fluid pressure produced in a hydrostatic device attached to some part of the output drive that displaced in response to torque inputs. Newer turboshaft engine torquemeters typically use electronic sensors to measure torsional deflection in a calibrated output shaft section.
The problem of shaft torque capacity can be quite significant in high power engines that have a forward PTO and the power turbine located aft. The PT shaft of these engines ends up having a modest diameter and long length. Many turboshaft engines (like the PT6) locate the PTO at the turbine outlet to avoid this problem.
Older turboshaft engine torquemeters often measured fluid pressure produced in a hydrostatic device attached to some part of the output drive that displaced in response to torque inputs. Newer turboshaft engine torquemeters typically use electronic sensors to measure torsional deflection in a calibrated output shaft section.
