Abstract: The invention relates to a medical turbine handpiece, in particular a dental turbine handpiece, having a drive shaft rotatably mounted in the front end region of the handpiece and to which a tool can be connected, as well as a turbine wheel arranged so as to be non-rotatable on the drive shaft and is arranged in a turbine chamber realized in the end region, into which turbine chamber a supply line for a flowing pressure medium for driving the turbine wheel opens out at an inlet opening and from which turbine chamber a removal line extends at an outlet opening, wherein at least one cross connecting channel for the pressure medium is realized in the wall of the turbine chamber, the cross connecting channel connecting the axially remote edge region of the turbine chamber to a region of the turbine chamber that is axially close to the drive shaft.

Abstract: A directed flow wind turbine is configured to utilize a laminar flow of an entering wind through the directed flow wind turbine and includes a plurality of rotor vanes mechanically coupled to an upper rotor ring and a lower rotor ring. A shaft is mechanically coupled to the upper rotor ring and the lower rotor ring and configured to receive torque from the plurality of rotor vanes. An upper housing plate is attached to the shaft with an upper bearing. A lower housing plate is attached to the shaft with a lower bearing. An upwind flow shield, a downwind flow shield, and a rotor protector shield are attached to the upper housing plate and the lower housing plate. Wherein dimensions of these components are controlled in order to maintain the laminar flow of the entering wind.

Abstract: A turbine engine stator stage includes a plurality of vanes with each of the plurality of vanes having a camber angle. The plurality of vanes is arranged in a plurality of groups with each group including a pre-determined sequence of vanes. The ordering of vanes within each group is determined by the camber of the individual vanes. This results in an arrangement of vanes within the stator stage which can modify the flow characteristics of the air entering the stator stage to reduce the circumferential pressure variation in the flow region immediately downstream of the stator stage.

Abstract: The embodiments herein disclose a system and method for providing an intrinsic safety to rotating machinery from the failure of internal high speed rotating structures. According to one embodiment herein, a system assembly comprises a unique design of the rotating structure to provide a sufficient safety margin and redundancy in configuration. The system assembly comprises a blower fan assembled inside a blower casing and rotated inside the casing. The fan is manufactured by a single forging process instead of an investment casting. The fan comprises several blades mounted to a hub in a shroud to draw a required quantity of fluid. The fan is mounted to a shaft through the hub. When the blower fan is rotated at a high speed exceeding the design parameters, a ‘rub and stop’ mechanism is initiated to halt the fan.

Abstract: Systems, methods, and devices relating to a mechanism which can be used in gas cooling devices, pneumatic motors, turbines and other pressurized gas devices. A rotatable rotor is provided along with a number of hollow conduits that radially radiate from an exit port at the center of the rotor. The pressurized gas is injected into the mechanism at the inlet port(s). The gas enters the conduits and travels from the inlet port(s) to the exit port(s). In doing so, the gas causes the rotor to rotate about its central axis while the gas cools. This results in a colder gas at the exit port(s) than at the inlet port(s).

Abstract: A fan control method, apparatus, and system, so as to implement speed regulation and rotation direction control on a four-wire system counter-rotating fan with a conventional four-wire fan interface by using a PWM control bus. The method provided by the embodiments of the present invention includes: receiving a first fan regulation and control signal sent by a system control module; converting the first fan regulation and control signal to a forward-rotating control signal, a counter-rotating control signal, or a rotation direction switchover control signal according to a duty cycle range of the first fan regulation and control signal and a current rotation direction of the fan; and sending a control signal obtained by the conversion to a fan driving module, so that the fan driving module drives, according to the control signal obtained by the conversion, the fan to operate.

Abstract: A pipe of an apparatus has a first gas in a first space and a second gas in a second space. The first gas is in the amount to generate a buoyancy force that exceeds at least a gravity force to position the apparatus in a stationary state at a predetermined distance relative to a reference surface. A fixture is coupled to the apparatus to secure the apparatus in the stationary state relative to the ground without supporting the apparatus. The first gas is lighter than the second gas. The pipe is capable of creating a flow of the second gas.

Abstract: A system for extracting foreign matter in a gas turbine includes multiple variable bleed valve (VBV) doors disposed on the outer engine casing between a low pressure compressor and a high pressure compressor for bleeding a portion of flow from a core engine flow path into a bypass flow path. The system includes an outlet guide vane (OGV) assembly having multiple guide vanes disposed within the core flow path and multiple support struts positioned downstream from the multiple guide vanes. Each pairs of adjacent support struts comprises at least one VBV door therebetween and a section of the OGV assembly located at an upstream side of the fan hub frame before the each pairs of adjacent support struts. Each section of the OGV assembly includes a first side with one or more guide vanes with trimmed trailing edges configured for directing flow into the at least one VBV door.

Abstract: Provided is a compressor control device configured to control a flow rate of a compressor having a plurality of impellers connected to an outlet port-side flow path in parallel and a flow rate regulation unit configured to regulate a flow rate of each of the impellers, the compressor control device including a pressure detection unit configured to detect a pressure of the outlet port-side flow path, a flow rate detection unit configured to detect the flow rate of each of the impellers, and a control unit configured to output a flow rate regulation command of each of the impellers to the flow rate regulation unit and control the flow rate regulation unit based on the detection result of the pressure detection unit.

Abstract: A turbocharger system and method for a vehicle, wherein the system comprises a high pressure turbocharger and a low pressure turbocharger. Both the high and low pressure turbochargers are driven by exhaust gas on an exhaust side of the turbochargers. The system further comprises a first bypass conduit that bypasses the low pressure turbocharger during set events.

Abstract: A gas turbine engine is disclosed having a vane disposed in a flow path of a gas turbine engine component, for example a gas turbine engine compressor. The vane is in thermal contact with a heat tube that extends through a wall of the engine component and into a space in which a thermal fluid passes. The thermal fluid can be at a different temperature than the vane such that heat is transferred between the two. In one embodiment the vane forms part of an intercooler for a compressor of the gas turbine engine. The vane can have a fin disposed at the end of the heat tube to facilitate a heat transfer.

Abstract: Provided are corrosive environment monitoring systems and methods whereby corrosive factors are measured in a steam turbine and a corrosive environment is correctly monitored. A corrosive environment monitoring system measures corrosive factors having a part in damaging and deteriorating structural members in a steam turbine and is configured in such a way that steam in the steam turbine is permitted to flow into the corrosive environment monitoring system. Furthermore, in the steam turbine, a condensing mechanism condenses steam that has flowed in and a corrosive factor measuring device is equipped with corrosive factor sensors that measure corrosive factors in condensed water generated by the condensing mechanism.

Abstract: A flow path surface of a gas turbine engine at the location of a bladed component is disclosed in which the flow path surface includes a cylindrical upstream side and a conical downstream side. The bladed component is located at the intersection of the cylindrical upstream side and the conical downstream side. The cylindrical upstream side can extend from a leading edge of the bladed component, or a point upstream of it, to a location between the leading edge and trailing edge of the component. The conical downstream side can extend past the trailing edge of the bladed component. The bladed component can be a fan blade or a compressor blade.

Abstract: Apparatus and method for determining a two-dimensional temperature distribution in a cross-sectional path of a hot-temperature flow in a turbine engine (10). A grid (22, 24, 38) is located in a path of a hot-temperature flow in the turbine engine. A thermal imager (34) has a field of view configured to sense infrared emissions from the grid. A processor (50) is configured to generate data indicative of a two-dimensional temperature distribution in a cross-sectional path of the flow based on the sensed infrared emissions.

Abstract: A cooling system for a turbine engine for directing cooling fluids from a compressor to a turbine blade cooling fluid supply and from an ambient air source to the turbine blade cooling fluid supply to supply cooling fluids to one or more airfoils of a rotor assembly is disclosed. The cooling system may include a compressor bleed conduit extending from a compressor to the turbine blade cooling fluid supply that provides cooling fluid to at least one turbine blade. The compressor bleed conduit may include an upstream section and a downstream section whereby the upstream section exhausts compressed bleed air through an outlet into the downstream section through which ambient air passes. The outlet of the upstream section may be generally aligned with a flow of ambient air flowing in the downstream section. As such, the compressed air increases the flow of ambient air to the turbine blade cooling fluid supply.

Abstract: The invention offers a steam turbine forced air cooling system, its method, and a steam turbine provided with the system, the system being of an inexpensive and simple device configuration and improving a cooling effect by the use of an easy-to-get device. Suction is applied to the steam introduction side of an HP turbine 4 or an IP turbine 9 by the use of cooling air suction ejectors 27, 28 which use a compressed medium other than steam as a drive source. The cooling air is then introduced from the steam exhaust portion of the steam turbine into the inside of the steam turbine and is discharged from the ejectors 27, 28 to the atmosphere.

Abstract: A system and method for controlling the acoustic signature of a turbomachine having a plurality of valves wherein an operating load is identified and an arc of admission across a plurality of nozzles is associated therewith. A valve sequencing scheme is selected and implemented to activate the arc of admission for a particular operating load so as to minimize valve noise by adjusting valves simultaneously rather than consecutively.

Abstract: A gas turbine engine according to an exemplary aspect of the present disclosure includes, among other things, a fan section including a fan rotatable about an engine axis with a plurality of fan blades rotatable about a fan blade axis. A geared architecture is in communication with the fan and driven by a turbine section. The fan rotates at a first speed and the turbine section rotates at a second speed different from the first speed and a fixed area fan nozzle in communication with the fan section.

Abstract: An aircraft (1) having a rotary wing (2) and turboshaft engines (11, 12, 13) for driving said rotary wing (2). The aircraft then includes two main engines (11, 12) that are identical, each capable of operating at at least one specific rating associated with a main power (maxTOP, OEIcont), and a secondary engine (13) capable of operating at at least one specific rating by delivering secondary power (maxTOP?, OEIcont?) proportional to the corresponding main power (maxTOP, OEIcont) in application of a coefficient of proportionality (k) less than or equal to 0.5, said aircraft having a control system (20) for driving the rotary wing by causing each main engine (11, 12) to operate continuously throughout a flight, and by using the secondary engine (13) as a supplement during at least one predetermined specific stage of flight.

Abstract: Certain embodiments of the disclosure may include systems and methods for boundary control during steam turbine acceleration. According to an example embodiment, the method can include receiving an indication the turbine is in an initial acceleration phase; receiving speed control parameter data from a plurality of sensors; receiving boundary control parameter data from a plurality of sensors; providing a control valve configured for controlling steam flow entering the turbine; determining the control valve position based on received speed control parameter data; determining the control valve position based on received boundary control parameter data; adjusting at least one boundary control parameter to the at least one boundary control parameter limit during turbine startup, wherein the value of a speed control parameter is simultaneously adjusted based on the adjusted at least one boundary control parameter; and adjusting the control valve position based at least on determined parameter data.

Abstract: The present disclosure refers to an impingement cooling arrangement for cooling a duct wall of a duct guiding a hot gas flow. The impingement cooling arrangement includes an impingement sleeve which is at least partly disposed in a compressed air plenum, and spaced at a distance to the duct wall to form a cooling flow path between the duct wall and the impingement sleeve such that cooling air injected from the compressed air plenum through apertures in the sleeve impinges on the duct wall. At least one flow diverter is arranged in the cooling flow path to divert the cross flow away from at least one aperture. Besides the impingement cooling arrangement a gas turbine with such an arrangement as well as a method for cooling a duct wall are provided.

Abstract: A seal gas delivery system for an end seal on a turbo machine rotor shaft includes a seal gas passageway for delivering a seal gas to the end seal and a seal gas distributor for receiving at least a portion of the seal gas from the seal gas passageway, the seal gas distributor having a plurality of holes for distributing the seal gas about the rotor shaft during turbo machine standstill; the holes are located on a cylindrical surface and are typically arranged all around said rotor shaft, preferably regularly all around said rotor shaft.

Abstract: According to one embodiment, an electronic device includes a fan, a temperature sensor and a controller. The temperature sensor is configured to output a value indicative of a detected temperature. The controller is configured to control a rotational speed of the fan. The controller is configured to keep the rotational speed of the fan constant when the value is within a first temperature zone or to change the rotational speed of the fan when the values is within a second temperature zone.

Abstract: An exhaust diffuser comprising an inner boundary and an outer boundary forming an annular gas path, and a plurality of strut structures extending radially within the gas path. Each of the strut structures include pressure and suction side walls, and a plurality of radially spaced flow injectors are formed in at least one of the pressure and suction side walls for injecting a fluid flow into the gas path adjacent to the strut structure. At least two fluid supply conduits provide a fluid flow to respective radially spaced flow injectors, and a flow control device is associated with each of the conduits to independently control a fluid flow from a fluid source to each of the radially spaced flow injectors.

Abstract: Embodiments of the present application include a gas turbine assembly. The gas turbine assembly may include a solid wheel, a turbine aft shaft, and an aft joint connecting the solid wheel to the turbine aft shaft. The turbine assembly also may include a cover plate positioned between the solid wheel and the turbine aft shaft. The cover plate may be configured to direct a flow of compressor extraction fluid inboard through the aft joint and out the turbine aft shaft.

Abstract: A system for controlling compressor forward leakage to the compressor flow path in a gas turbine is provided. The system includes a first compressor rotor wheel coupled to an upstream face of a compressor spacer wheel. A second compressor rotor wheel is coupled to a downstream face of the compressor spacer wheel. The compressor spacer wheel includes at least one intake recess defined in the downstream face, at least one discharge recess defined in the upstream face, and at least one axial passage coupling the at least one intake recess in fluid communication with the at least one discharge recess.

Abstract: The systems, methods, and computer-readable media set a gas turbine firing temperature to maintain gas turbine metal surface temperatures. In certain embodiments, a method of setting a gas turbine firing temperature is disclosed that may comprise determining a critical temperature at which ash from ash bearing fuels becomes unremovable by conventional water wash procedures, determining hot gas path component metal surface temperatures, and adjusting the gas turbine firing temperature to maintain the metal surface temperatures below the critical temperature. Determining the metal surface temperatures may be based at least in part on measured gas turbine parameters, gas turbine performance models, and empirical models.

Abstract: A Method that consists of changing power of the payload and moment of resistance on the shaft of the wind generator in proportion to current wind speeds, and reduce speed of an air flow at meeting with blades of the wind engine of proportionally angular speed of a rotor. Wind generator for realization of the above Method contains blades formed by crossing of sectors of cavity cylinders under sharp corners to a direction of an air flow, and the depth of a cavity formed by crossing of sectors, exceeds distance between their forward borders, the internal surface of a cavity is executed with high frictional properties, and the outside surface of blades is executed with the minimal frictional properties. Wind generator for realization of the above Method must contain at least two electric generators, mechanical transmission and an automatic control system. Electric generators can be used from automobile industry.

Abstract: The present application provides a hot gas path component for use in a hot gas path of a gas turbine engine. The hot gas path component may include an internal wall, an external wall facing the hot gas path, an impingement wall, a number of internal wall pedestals positioned between the internal wall and the impingement wall, and a number of external wall pedestals positioned between the external wall and the impingement wall.

Abstract: An example turbomachine geared architecture support assembly includes a subpart having a more compliant portion and a less compliant portion. The less compliant portion includes a stop that limits axial movement of a geared architecture within a turbomachine.

Abstract: A method for stopping the operation of a wind turbine is disclosed. The method may generally include receiving signals associated with at least one operating condition of the wind turbine, analyzing the at least one operating condition with a controller of the wind turbine, implementing a first stopping procedure in order to stop operation of the wind turbine when analysis of the at least one operating condition indicates that a pitch system failure has occurred and implementing a second stopping procedure in order to stop operation of the wind turbine when analysis of the at least one operating condition indicates that a different wind turbine stop event has occurred.

Abstract: A method for adjusting a barometric cell may include coupling the barometric cell to a control device via an actuating rod. The actuating rod may be movably mounted on a charging device in any desired position. The method may include applying a freely selectable pressure to the barometric cell so as to bring the actuating rod into contact with a stop, adjusting the barometric cell until a sensor registers a predefined value, and fixing the barometric cell on the charging device.

Abstract: The invention relates to a method for controlling a turbine which is characterized by a hidden state at each point in time of the control. The dynamic behavior of the turbine is modeled using a recurrent neural network comprising a recurrent hidden layer. The recurrent hidden layer is formed by vectors of neurons which describe the hidden state of the turbine at the points in time of the control. For each point in time, two vectors are connected chronologically to a first connection which bridges one point in time, and two vectors are additionally connected chronologically to a second connection which bridges at least two points in time. Short-term effects can be corrected by means of the first connections, and long-term effects can be corrected by means of the second connections. Emissions and occurring dynamics can be minimized in the turbine by means of the latter. The invention further relates to a control device and a turbine comprising such a control device.

Abstract: A pump has a housing that defines a pump chamber (200) with a fluid inlet and outlet (26, 28). An impeller (30) is mounted for rotation in the pump chamber. A raceway (40) is in floating axial relationship with the impeller and divides the pump chamber into an inlet chamber (202), an impeller chamber (204) and a discharge chamber (206). The raceway has preferably two flow channels, in separated end-to-end arrangement. Each flow channel has an inlet passage and an outlet passage, establishing a fluid conduit from the inlet chamber to the impeller chamber and then to the discharge chamber. A spring (60) provides resistance to axial movement of the raceway away from the impeller. A seal chamber (42) formed on the raceway and pressurized by the fluid, urges the raceway towards the impeller.

Abstract: A fluid processing device may include a rotatable shaft, a driver configured to drive the rotatable shaft, a separator installed on the rotatable shaft, and a supersonic compressor fluidly communicating with the separator.

Abstract: Methods and apparatus to adjust bleed ports on an aircraft engine are disclosed. An example apparatus for bleeding air from a multi-stage compressor of an aircraft engine includes a compressor case having a plurality of bleed ports. A first bleed port is associated with a first stage of a compressor, and a second bleed port is associated with a second stage of the compressor. The apparatus includes a plenum connected to the compressor case to define a plenum cavity. The plenum fluidly coupling the first and second bleed ports to a fluid conduit for providing bleed air to one or more systems of an aircraft. The apparatus also includes a bleed port selection mechanism located within the plenum cavity. The bleed port selection mechanism including a first portion proximate the first bleed port and operable to prevent fluid flow through the first bleed port.

Abstract: A seal assembly for sealing a fluid passageway from contaminants is disclosed. The fluid passageway is formed by a rotating shaft entering an opening in a housing. The fluid passageway connects an interior of the housing, and any exterior of the housing. The seal assembly includes a first sealing member and a second sealing member, which divides the fluid passage into an interior section, an open section, and a sealed section. The interior section is exposed to the interior of the housing. The sealed section is fluidly sealed between the interior section and the open section. A sensor is disposed within the sealed section. The sensor is configured to sense the contaminants within the sealed section and is electronically coupled to a controller configured to send an alarm signal. The sensor is a moisture sensor and extends into an annular recess formed in the stationary member.

Abstract: A compressor for a gas turbine engine with variable inlet guide vanes each defining an airfoil portion twisted such that at each location of the airfoil portion along the pivot axis, an angle is defined between a respective chord extending between the leading and trailing edges and a same reference plane containing the pivot axis and extending radially with respect to the compressor. The angle, which is measured along a direction of rotation of the rotor, varies from a minimum value near the hub side wall to a maximum value near the shroud side wall. A method of reducing vortex whistle in a radial inlet of a compressor is also provided.

Abstract: A gas turbine engine includes a bearing structure mounted to the front center body case structure to rotationally support a shaft driven by a geared architecture. A bearing compartment passage structure is in communication with the bearing structure through a front center body case structure.

Abstract: A turbine-pump system adapted for use with well liquid that is displaceable within a well conduit. The turbine-pump system may include a bowl assembly; and a bowl support device fixedly attachable to the bowl assembly and selectively engageable with the well conduit for holding a portion of the bowl assembly in substantially axially, radially and rotationally fixed relationship with the well conduit.

Abstract: The present invention relates to a method of decelerating a turbine rotor of a turbine engine. At least one electric motor is engaged with the turbine rotor. A braking system, preferably the starting system, is engaged with the at least one electric motor, preferably the generator of the turbine engine, so as to use the at least one electric motor to apply a negative (braking) torque on the turbine rotor. The method includes after flame off, the braking system being used for dissipating kinetic energy available in the turbine engine after flame off by means of the at least one electric motor.

Abstract: A method to design a turbine including: estimating rates of thermal radial expansion for each of a stator and a rotor corresponding to a period of operation of the turbine; estimating a clearance between the rotor and the stator based on the rates of thermal radial expansion, and determining a mass or surface area of the stator or rotor based on the clearance.

Abstract: A turbine-pump system bowl assembly for use with flowing liquid in a liquid conduit has an impeller subassembly that includes multiple axially abutting impeller members.

Abstract: An active clearance control system for a gas turbine engine includes a structural member that is configured to be arranged near a blade tip. A plenum includes first and second walls respectively providing first and second cavities. The first wall includes impingement holes. The plenum is arranged over the structural member. A fluid source is fluidly connected to the second cavity to provide an impingement cooling flow from the second cavity through the impingement holes to the first cavity onto the structural member. A method includes the steps of providing a conditioning fluid to an outer cavity of a plenum providing an impingement cooling flow through impingement holes from an inner wall of the plenum to an inner cavity, directing the impingement cooling flow onto a structural member, and conditioning a temperature of the structural member with the impingement cooling flow to control a blade tip clearance.

Abstract: A turbocharger assembly can include a housing with a through bore and an axial face disposed in the through bore; a locating plate with a keyed opening attached to the housing; and a journal bearing disposed in the through bore where the journal bearing includes a keyed compressor end and an enlarged outer portion defined between two axial faces by an outer diameter and an axial length where the axial face disposed in the through bore of the housing, the locating plate, and the two axial faces of the journal bearing axially locate the journal bearing in the through bore and where the keyed opening of the locating plate and the keyed compressor end of the journal bearing azimuthally locate the journal bearing in the through bore. Various other examples of devices, assemblies, systems, methods, etc., are also disclosed.

Abstract: A supersonic compressor rotor and method of compressing a fluid is disclosed. The rotor includes a first and a second rotor disk, a first set and a second set of rotor vanes. The first set and second set of rotor vanes are coupled to and disposed between the first and second rotor disks. Further, the first set of rotor vanes are offset from the second set of rotor vanes. The rotor includes a first set of flow channels defined by the first set of rotor vanes disposed between the first and second rotor disks. Similarly, the rotor includes a second set of flow channels defined by the second set of rotor vanes disposed between the first and second rotor disks. Further, the rotor includes a compression ramp disposed on a rotor vane surface opposite to an adjacent rotor vane surface.

Abstract: A gas turbine engine control apparatus comprises a controller 34, a memory 36 associated with the controller 34 and inputs 38 for measurement data from an engine. The controller 34 determines the start of a monitoring cycle at 73, receives measurement data at the inputs 38 during the monitoring cycle, manipulates the measurement data to provide an incremental deterioration value representing deterioration occurring within the engine and during the monitoring cycle, and uses the incremental deterioration value at 72 to update a deterioration value 74 stored in the memory 36, and determines the start of a further monitoring cycle.

Abstract: Gas turbine engine, broadband damping systems, and methods for producing broadband-damped gas turbine engine are provided. In one embodiment, the gas turbine engine includes an engine case, a rotor assembly mounted within the engine case for rotation about a rotational axis, and a broadband damping system disposed between the rotor assembly and the engine case. The broadband damping system includes a first set of three parameter axial dampers angularly spaced around the rotational axis, and a second set of three parameter axial dampers angularly spaced around the rotational axis and coupled in parallel with the first set of three parameter axial dampers. The first and second sets of three parameter axial dampers are tuned to provide peak damping at different rotational frequencies to increase the damping bandwidth of the broadband damping system during operation of the gas turbine engine.

Abstract: A pump for a dishwasher is configured as an impeller pump having a central water inflow to a rotating impeller for conveying the water in the radial direction out of the impeller into a pump chamber which surrounds the impeller in a ring-like manner and has a heated pump chamber wall on its outer side. Here, the pump has an outlet in the end region of the pump chamber at an axial spacing from the impeller. Heating elements which have a decreasing power output with regard to the area power output in the axial direction of the pump toward the outlet are arranged on the pump chamber wall. An input of energy into the pump chamber can thus be varied and in the process adapted depending on a turbulent or laminar flow.

Abstract: A method for optimizing performance of a compressor by adjusting the position of an inlet guide vane and the speed of a drive unit. In one embodiment, the method can compare measured values for operating flow rate and operating pressure for a combination of operating settings for the position and the speed against threshold values for each of these measured values. In this way, the method can identify “how” the compressor is operating and equate such operation to one of a plurality of operation scenarios. In turn, the method can provide an adjustment to one or both of the speed and the position that corresponds with such operating scenario. The method can also vet the selected adjustment to avoid operation of the compressor outside of its safe operating configurations, as defined for example by minimum and maximum values for the position of the inlet guide vane and the speed of the drive unit.