Examples described herein provide a method for overspeed protection of a motor of a gate crossing mechanism. The method includes monitoring, by an overspeed protection circuit, a voltage across a first Zener diode and a second Zener diode. An anode of the first Zener diode is connected to an anode of the second Zener diode. The method further includes, responsive to determining that a Zener voltage threshold is exceeded, allowing a current to flow into a gate pin of a triac. The triac controls the motor of the gate crossing mechanism.

A probe adapter includes an adapter body including a probe aperture and a slot. The probe adapter further includes a driver slidably mounted within the slot and slidable between a first position and a second position. The driver includes a first end and a second end opposite the first end. The first end includes a ramped recess extending in a direction from the first end toward the second end. The probe adapter further includes a threaded fastener configured to contact the second end of the driver so as to retain the driver in the first position.

Methods and systems for detecting a shaft event of a gas turbine engine are described. The method comprises monitoring at least one engine parameter and comparing the at least one engine parameter to a schedule for the at least one parameter defining a first threshold and a second threshold greater than the first threshold; applying a limit to the at least one engine parameter when the at least one engine parameter is inside a parameter limiting region between the first threshold and the second threshold, the first threshold separating the parameter limiting region from a normal operating region, the second threshold separating the parameter limiting region from a hazardous operating region; and detecting the shaft event when the at least one engine parameter crosses the second threshold and issuing a signal in response to the detecting.

Methods and systems for detecting a shaft event of a gas turbine engine are described. The method comprises monitoring at least one engine parameter and comparing the at least one engine parameter to a schedule for the at least one parameter defining a first threshold and a second threshold greater than the first threshold; applying a limit to the at least one engine parameter when the at least one engine parameter is inside a parameter limiting region between the first threshold and the second threshold, the first threshold separating the parameter limiting region from a normal operating region, the second threshold separating the parameter limiting region from a hazardous operating region; and detecting the shaft event when the at least one engine parameter crosses the second threshold and issuing a signal in response to the detecting.

A multi-mode microwave waveguide blade sensing system includes a transceiver, a waveguide, and a probe sensor. The transceiver generates a microwave energy signal having a first waveguide mode and a different second waveguide mode. The waveguide includes a first end that receives the microwave energy signal. The probe sensor includes a proximate end that receives the microwave energy signal from the transceiver and a distal end including an aperture that outputs the microwave energy signal. The probe sensor directs the microwave energy signal at a first direction based on the first waveguide mode and a different second direction different based on the second waveguide mode. The probe sensor receives different levels of reflected microwave energy based at least in part on a location at which the at least one microwave energy signal is reflected from the machine.

This single-shaft combined cycle plant comprises: a power generator; a gas turbine; a steam turbine that is driven by using waste heat from the gas turbine, and is connected to the power generator by a clutch when the rotational speed syncs with the rotational speed of the gas turbine; a steam turbine over-rotation prevention device; a gas turbine over-rotation prevention device; and a control device. The control device sets the power generator to an unloaded state and, whilst maintaining the rotational speed Ng of the gas turbine so as to be higher than the rotational speed Ns of the steam turbine and lower than the maximum rotational speed Nglim of the gas turbine, increases the rotational speed Ns of the steam turbine to the maximum rotational speed Nslim of the steam turbine (time t2-t4) and tests whether or not the steam turbine over-rotation prevention device operates normally.

This single-shaft combined cycle plant comprises: a power generator; a gas turbine; a steam turbine that is driven by using waste heat from the gas turbine, and is connected to the power generator by a clutch when the rotational speed syncs with the rotational speed of the gas turbine; a steam turbine over-rotation prevention device; a gas turbine over-rotation prevention device; and a control device. The control device sets the power generator to an unloaded state and, whilst maintaining the rotational speed Ng of the gas turbine so as to be higher than the rotational speed Ns of the steam turbine and lower than the maximum rotational speed Nglim of the gas turbine, increases the rotational speed Ns of the steam turbine to the maximum rotational speed Nslim of the steam turbine (time t2-t4) and tests whether or not the steam turbine over-rotation prevention device operates normally.

A method for stopping an engine of a rotorcraft in overspeed, the rotorcraft comprising at least one engine, the engine comprising a gas generator and a power assembly, the power assembly comprising at least one power turbine rotated by gases originating from the gas generator, the power assembly comprising at least one power shaft rotationally secured to the power turbine, the power assembly rotating about a longitudinal axis at a speed referred to as the “speed of rotation”. The method comprises steps consisting in measuring a current value of the speed of rotation, determining a time derivative of the current value of the speed of rotation, referred to as the “current derivative $\left(\frac{dN2i}{dt}\right)”,$
and automatically stopping the engine when the current derivative $\left(\frac{dN2i}{dt}\right)$
changes sign.

A method for stopping an engine of a rotorcraft in overspeed, the rotorcraft comprising at least one engine, the engine comprising a gas generator and a power assembly, the power assembly comprising at least one power turbine rotated by gases originating from the gas generator, the power assembly comprising at least one power shaft rotationally secured to the power turbine, the power assembly rotating about a longitudinal axis at a speed referred to as the “speed of rotation”. The method comprises steps consisting in measuring a current value of the speed of rotation, determining a time derivative of the current value of the speed of rotation, referred to as the “current derivative $\left(\frac{dN2i}{dt}\right)”,$
and automatically stopping the engine when the current derivative $\left(\frac{dN2i}{dt}\right)$
changes sign.

A gas turbine engine includes, among other things, a fan, a fan drive gear system that is coupled with the fan and a fan drive input shaft, a compressor section that includes a first compressor and a second compressor, and a turbine section. The turbine section includes a first turbine coupled with a first shaft and a second turbine coupled through a second shaft to the second compressor. A bearing supports the fan drive input shaft. The bearing is located proximal to, and radially spaced from, a forward end of the first shaft. The bearing includes a speed sensor target that is rotatable with the forward end and that defines a rotation path. A speed sensor probe is situated proximal to the rotation path and is operable to read the speed sensor target.