Abstract: A method for supplying air to an engine of an aircraft via an air supply system of the aircraft. A dynamic air intake vent of the system can be closed by a closure member that is movable between a closed position and an open position. A static air intake vent is equipped with a filter medium. During flight, the method comprises an unfiltered operating mode that comprises the following steps: positioning of the closure member in the open position, and, during a phase of forward travel of the aircraft, dynamic intake of a flow of air, then transfer of a first portion of the flow of air to the engine and a second portion of the flow of air to the filter medium in order to clean the filter medium.

Abstract: A gas-sensing apparatus with gas convection capability includes a gas sensor mounted inside a container, a substrate forming a bottom plate of the container and an actuator. The gas sensor is mounted over a first surface of the substrate internal to the container. The actuator is coupled to a second surface of the substrate external to the container. The actuator can cause convection of a gas within the container by enabling movements of the substrate in response to an activation signal.

Abstract: A filtering assembly that receives an inlet air includes a modulation panel subassembly, an air filter subassembly downstream of the modulation panel subassembly, wherein the air filter subassembly is configured to discharge the inlet air from the filtering assembly, and an arm subassembly configured to move the modulation panel subassembly and to move the air filter subassembly. The air filter subassembly moves into and out of a flow of the inlet air.

Abstract: Systems and methods for monitoring quality of filters within a filtering system are disclosed. The system includes at least one pressure sensor which monitors a force applied by a filter on a filter housing. The system further includes a control system which provides notification to a user when the force measured by the at least one pressure sensor exceeds a predetermined threshold value.

Abstract: A laparoscopic filter system having a main unit having an inflow port, an outflow port, a pressure sensing port, a user interface having a power switch, a controller, a pump, and an interface for receiving a detachable filter cartridge, and a detachable filter cartridge configured and arranged to reversibly attach to the interface, the detachable filter cartridge having an inflow pass-through line, an outflow pass-through line, a pressure sensing pass-through line, and a filter media arranged in series with the inflow pass-through line.

Abstract: A system including an air intake subsystem having a housing is provided. A coalescer having a frame is disposed inside the housing. The system includes a mounting bracket, and a release mechanism coupled to the frame and the mounting bracket. The release mechanism is adapted to selectively release the frame.

Abstract: A purification arrangement for a gas pipeline system includes a pressure vessel and at least a modular separator assembly and a modular filter assembly in the interior of the pressure vessel. A gas flow may be established through the pressure vessel, and the gas may pass through the modular separator and filter assemblies to remove liquid and/or solid particulates from the gas.

Abstract: Systems and methods are provided for an air purifier with over pressurization relief, including the following components. A room air inlet is configured to fluidly receive air from a room. A supply duct inlet is configured to fluidly receive air from a forced air system. An air filter and or air purification means is configured to filter/purify air. An outlet is configured to expel filtered/treated air into the room. A bypass damper system has at least one air filtering mode position and a bypass mode position. A pressure control mechanism is configured to automatically allow the bypass damper system to move from at least one air filtering mode position to a bypass mode position when the air received from the supply duct inlet exceeds a bypass threshold. The bypass mode position guides air from the supply duct inlet into the room without requiring passage through the filter and the outlet.

Abstract: A purification arrangement for a gas pipeline system includes a pressure vessel and at least first and second purification assemblies in the interior of the pressure vessel. An openable/closable barrier is positioned in the pressure vessel between the first and second purification assemblies. A gas flow may be established through the pressure vessel, and the gas may pass through the first purification assembly, the open barrier, and the second purification assembly to remove liquid and/or solid particulates from the gas.

Abstract: Various embodiments of the present disclosure provide a portable industrial air filtration device employing an annular dual filter assembly to capture and remove impurities from the air surrounding the air filtration device, enabling the air filtration device to quickly and efficiently improve the quality and safety of the air. The air filtration device includes a two-piece housing including a lower housing component and a locking cover removably attachable to the lower housing component. The dual filter assembly is mounted within the housing between the locking cover and the lower housing component, and includes a removable self-supporting outer pre-filter surrounding a separately removable inner HEPA filter. The pre-filter initially filters the surrounding air by capturing relatively large or coarse impurities, and the HEPA filter further filters the air pulled through the pre-filter by capturing relatively small or fine impurities.

Abstract: An air dryer cartridge having an outer shell, an inner shell positioned within the outer shell, and a check valve positioned at least partially between the inner and outer shells. The inner and outer shells each have an inlet and an outlet. The outer shell is preferably operable to removably engage an air dryer. The check valve is operable to regulate the rate of flow of fluid through the outlet of the inner shell. Preferably, the check valve also seals between portions of the inner and outer shells and/or is operable to sealingly engage an air dryer.

Abstract: An inlet air treatment system and method comprises a used coalescer having intake air passing therethrough and an unused coalescer not having intake air passing therethrough. A mechanism automatically adjusts the inlet air treatment system such that the used coalescer is no longer in the airflow and the unused coalescer is in the airflow.

Abstract: A purification arrangement for a gas pipeline system includes a pressure vessel and at least first and second purification assemblies in the interior of the pressure vessel. An openable/closable barrier is positioned in the pressure vessel between the first and second purification assemblies. A gas flow may be established through the pressure vessel, and the gas may pass through the first purification assembly, the open barrier, and the second purification assembly to remove liquid and/or solid particulates from the gas.

Abstract: A virtual impactor includes a jet nozzle that jets, from a jet outlet, a gas that contains particles, an opposing nozzle that is disposed with a specific separation distance from the jet nozzle and draws in, as a secondary flow, from a vacuum inlet at one end portion, a portion of the gas that is jetted from the jet nozzle, and a variable mechanism that varies at least one of a width of the jet outlet, the specific distance, and a width of the vacuum inlet.

Abstract: A cam shaft has a tubular part extending longitudinally along an axis and a helical body fixed in the tubular part and having a first helical passage extending between an inlet end where a first pressure is present and an outlet end where a second pressure is present. This helical body forms an oil separator between the inlet and outlet ends. A flow-blocking element at the inlet end moves as a function of a pressure differential between the first and second pressures to open and close the first helical passage.

Abstract: An exhaust gas analyzing apparatus provided a first filter flow path with a first filter, a second filter flow path provided with a second filter, an exhaust gas analyzing part for analyzing exhaust gas passing through the first filter or the second filter, a flow path switching mechanism for switching between the first filter flow path and the second filter flow path. A pulse purge mechanism is provided for supplying purge gas to the filters, in the filter flow paths, in a pulsed manner, and in the case where a pressure difference between an upstream side and a downstream side of the filter provided in one filter flow path where the exhaust gas flows becomes equal to or larger than a predetermined value, the one filter flow path is switched to the other one, and purge gas is supplied to the filter provided in the one filter flow path in the pulsed manner.

Abstract: A transportable field containment system with transparent hood. The transportable field containment system being easily and rapidly deployable and transportable by virtue of its relatively small size and light weight, a collapsible transparent hood that covers the containment area over a work site on the ground, the hood including detachable or folding side panels and removable door panels. The system preferably includes an exhaust component that creates negative air pressure in the containment area under the hood, thereby drawing air that contains hazardous substances, that may be released while the work is being conducted, through one or more off-gas filters.

Abstract: A chamber air cleaner apparatus may include a chamber housing mounted through a connector onto an air hose wherein the air hose may be connected to a main air cleaner, an intake duct attached to an outer surface of the chamber housing wherein exterior air may be introduced into the chamber housing through the intake duct, a variable valve pivotally installed in the vicinity of the intake duct and selectively opening according to an air suction pressure applied thereto, and a filter element mounted between the intake duct and the connector within the chamber housing to purify the introduced air through the intake duct.

Abstract: A hollow body includes an integrated oil separator unit, a swirl generator located in a cavity of the hollow body, at least one first supply opening in the camshaft case for introducing gas that is charged with oil into the cavity, and at least one discharge opening for carrying away separated oil and for carrying away gas that has been cleaned of oil. The swirl generator also has elements that are used to variably influence the pressure prevailing at a predetermined point in the cavity.

Abstract: A moving granular bed includes a filter granule channel, an inlet unit of gas, an outlet unit of gas, a first detecting unit and a feedback control unit. The inlet unit of gas is disposed at one side of the filter granule channel, and the dirty gas is fed into the filter granule channel through the inlet unit of gas. The inlet unit of gas has a first flow-guiding plate. The outlet unit of gas is disposed at the other side of the filter granule channel. The first detecting unit detects the gas velocity at the inlet unit of gas site. The feedback control unit is electrically connected with the first detecting unit, and controls the angle of the first flow-guiding plate and flow rate of filter granules according to a detecting result of the first detecting unit. A gas guiding system used in the moving granular bed is also disclosed.

Abstract: A hollow body, in particular a camshaft, is provided. The hollow body includes an integrated oil separator unit, a swirl generator being located in a cavity of the hollow body and the hollow body having at least one supply opening in the camshaft case for introducing gas that is charged with oil into the cavity and at least one discharge opening for carrying away separated oil and gas that has been cleaned of oil. The hollow body has an oil separator ring inside the cavity, downstream of the swirl generator when viewed in the flow direction.

Abstract: A separator for separating contaminants from a fluid stream has first and second chambers coupled by an aperture through which fluid can pass. An actuator can adjust the crossectional area of the aperture according to a pressure differential between the first chamber and a pressure reference. An impaction surface can deflect the first fluid stream after it enters the second chamber such that contaminants are separated from the stream. A pump generates a pressure differential across the aperture. It includes a third chamber having a second inlet for receiving a second fluid stream into the third chamber. The second inlet includes a convergent nozzle for accelerating the second fluid stream, and a third inlet for receiving the first fluid to stream downstream of the impaction surface, the third inlet being arranged relative to the second inlet such that the second fluid stream can entrain and accelerate the first fluid stream.

Abstract: A device for filtering nanoparticulate matter below 300 nm in size from ambient air within a defined enclosed space comprises at least one filter medium containing at least one filter material, and a fan or blower, which blows or draws the air through the filter medium does so with sufficiently low air velocity in the filter medium that the air has a long residence time in the filter medium, during which time adhesive encounters between nanoparticulate matter and the solid phase of the filter material are highly probable. This air velocity is also being sufficiently low to ensure that, once adhesion has taken place, kinetic de-adhesion by the air flow is highly improbable. Such a device allows to keep the nanoparticle count inside the enclosed space kept below 5000/cc, equivalent to ‘natural woodland’, even though external levels may exceeded 200,000/cc: the removal of nanoparticles by cleaning making this <2.5% the external count.

Abstract: A natural gas reclaimer device includes a pressure vessel with an inlet port and an outlet port. A conditioner is disposed in the pressure vessel to remove contaminants and stabilize the flow of natural gas received by the inlet port and prior to releasing the natural gas from the outlet port for subsequent use.

Abstract: A gas liquid separator system for a hydrogen generating apparatus includes a collection area for collecting liquid from the generated gases. To empty the collection area occasionally so that liquid does not build up and become entrained again in the dried gas, a vent solenoid is provided in communication with the collection area and a pump is used to create a vacuum periodically on the electrolysis cells. Such arrangement is used to open the liquid gas filter and possibly just the sump to atmosphere occasionally and vacuum generated to draw the liquid from the sump back to the electrolysis cells.

Abstract: A hollow body, in particular a camshaft, is provided. The hollow body includes an integrated oil separator unit, a swirl generator being located in a cavity of the hollow body and the hollow body having at least one supply opening in the camshaft case for introducing gas that is charged with oil into the cavity and at least one discharge opening for carrying away separated oil and gas that has been cleaned of oil. The hollow body has an oil separator ring inside the cavity, downstream of the swirl generator when viewed in the flow direction.

Abstract: An aspect of embodiments of the invention is to lower fluid resistance applied to gas flow (A, S) flowing within a dust collection system (1) so as to enhance dust collection efficiency of the dust collection system (1) without depending on the number or the two dimensional arrangement of movable elements (40) within the system (1). Embodiments of the dust collection system (1) of the invention includes: a housing (10) defining a cavity (50) therewithin, the housing (10) having a plurality of inlets (53) and at least one outlet (57) for gas; a plurality of movable elements (40) for opening and closing the inlets (53), the movable elements (40) being respectively provided corresponding to each of the inlets (53); a gas flow generating device (20) for generating a gas flow (A, S) from each of the inlets (53) to the outlet (57) during the opening operation of the movable elements (40); and a flow path control device (13) for controlling the flow paths of the gas flow (A, S).

Abstract: Liquid separator provided with a vessel (2) Which defines a space which is sealed at the top by means of a lid (7) in which is situated an outlet (8), whereby a pipe (11) is provided in the above-mentioned space on the one hand, extending round the above-mentioned outlet (8) in the above-mentioned space, as of the above-mentioned lid (7), and a fine filter (5) on the other hand, which also extends in the space round the above-mentioned outlet (8) and as of the above-mentioned lid (7), such that between the pipe (11) and the fine filter (5) is defined an outlet zone which is connected to the environment by means of a safety valve (21), characterised in that the safety valve (21) is connected to the above-mentioned outlet zone via a passage (19) in the lid (7).

Abstract: An apparatus for rotary dumping of rail cars, including a backside airflow diverter, a backside hood for removing contaminated air from the back side of the pit and at least two baffles on a rotational frame, the baffles each presenting a leading edge that contacts the backside airflow diverter during at least a portion of rotational motion. At least one air intake is positioned to pass through the upper surface of the backside diverter into the backside hood at a location where pressure in the backside hood is maintained at a substantially neutral or negative level even when pressure in the material receiving pit is increased by a down rush of air caused by the exit of the load from the railcar.

Abstract: A drying system (100) for use in drying out a water-damaged structure includes a blower (105) for providing outside air to the water damaged structure. An indirectly fired furnace (101) is used for heating the outside air prior to its introduction into the water-damaged structure. An exhaust blower (114) removes humid air from the water-damaged building, and one or more remote temperature and humidity sensors (117) are used for controlling the furnace air temperature and supply blower volume. An air intake filter box (111) is used for adding make-up air to recirculated building air and promoting cooling within accompanying trailer. A differential air pressure transmitter (118) controls the volume of moist air removed from the water damaged building to an optimal rate.

Abstract: An exhaust gas purifying apparatus for an internal combustion engine includes a collector, a differential pressure sensing device, a differential pressure based estimating device, a partition wall exposure sensing device, and a second regenerating device. The collector captures exhaust particles in exhaust gas. The differential pressure sensing device senses a differential pressure across the collector. The differential pressure based estimating device estimates an accumulation amount of the exhaust particles based on the differential pressure. The partition wall exposure sensing device senses a partition wall exposure state. The second regenerating device forcibly completely combusts the exhaust particles captured in the collector when the partition wall exposure sensing device senses the partition wall exposure state.

Abstract: A natural gas reclaimer device includes a pressure vessel with an inlet port and an outlet port. A conditioner is disposed in the pressure vessel to remove contaminants and stabilize the flow of natural gas received by the inlet port and prior to releasing the natural gas from the outlet port for subsequent use.

Abstract: A filter assembly comprising a housing having an air inlet and an air outlet and a filter chamber disposed between the inlet and the outlet, the housing having an air flow path there through. A filter element having a first surface area maybe located within the filter chamber and oriented such that the first surface area is angled with respect to the air flow path. The filter element may comprise a filter media adapted to remove contaminants from the air. A drain may be associated with the housing and adapted to remove contaminants filtered out of the air.

Abstract: A positive crankcase ventilation oil mist separator system has a first separator unit, wherein the first separator unit includes at least one filter body arranged in a blow-by gas path such that blow by gas flows through the filter body; a second separator unit, wherein the second separator is an impactor separator arranged in a bypass path that bypasses the first separator unit; and a bypass valve, which opens the bypass path as soon as a differential pressure at the first separator unit exceeds a predefined value, wherein the second separator unit comprises an impact wall formed by a section of the filter body of the first separator unit, and a flow directing element which directs the blow-by gas flow against the impact wall when the blow-by gas path is open.

Abstract: System for a dust filter unit includes dust detector to measure dust concentration in an outlet conduit of the filter unit. A controller establishes the detected dust concentration following a cleaning cycle of a filter of the unit and in one form compares that detected concentration to a baseline concentration to identify whether there is possible leak in the filter. The system also includes monitoring arrangements to measure pressure profiles in the unit to assess the state of values and/or filters in the unit. Methods of detecting the state of a filter unit are also described.

Abstract: A trap device (18) for removing species from a gas stream drawn from an enclosure by a vacuum pump is described, the device (18) comprising a casing having an inlet (16) for receiving the gas stream, an outlet (20) for exhausting the gas stream from the casing, and first and second chambers (136, 138) each for receiving the gas stream from the inlet and conveying the gas stream to the outlet; means (170, 174) for selectively diverting the gas stream from the inlet to a selected one of the chambers; a first plurality of cartridges (32) each being removably insertable into the casing to provide a plurality of flow passages for gas passing through the first chamber; and a second plurality of cartridges (132) each being removably insertable into the casing to provide a plurality of flow passages for gas passing through the second chamber, each flow passage extending between an inlet and an outlet of a respective cartridge, each cartridge housing means for removing species from the gas passing therethrough as soli

Abstract: A filtering device for an engine or a for power unit with a radial air intake, includes a ring-shaped filter for covering the radial air intake, characterised in that the ring-shaped filter includes a first fixed part and a second mobile part which is movable with respect to the first fixed part through actuator elements, from a filtering position in which the whole radial air intake is covered by the ring-shaped filter, to a bypass position in which the second mobile part uncovers at least partly the radial air intake.

Abstract: An improved air/oil separating PCV apparatus is disclosed that provides for integration of an air duct, cross-over duct, one way drain valve, PCV valve, cyclonic oil mist separator assembly, cyclone bypass valve, oil reservoir and oil fill cap into a single injection molded apparatus. The improved air/oil separating PCV apparatus is configured to permit it to be tooled in a vertical direction for injection molding.

Abstract: A particulate filter may comprise an inlet end, an outlet end, and a plurality of channels disposed and configured to flow fluid from the inlet end to the outlet end, wherein the channels are defined by porous walls configured to trap particulate matter. The porous walls may have a cell density less than about 200 cpsi, a wall thickness of less than about 14 mils, a median pore size that ranges from about 13 micrometers to about 20 micrometers, a total porosity greater than about 45%, and a pore size distribution such that pores less than 10 micrometers contribute less than about 10% porosity.

Abstract: An inertial gas-liquid separator removes liquid particles from a gas-liquid stream and has a variable orifice area variable along an axial direction and dependent upon axial movement of a plunger relative to a housing sleeve.

Abstract: An aspect of embodiments of the invention is to lower fluid resistance applied to gas flow (A, S) flowing within a dust collection system (1) so as to enhance dust collection efficiency of the dust collection system (1) without depending on the number or the two dimensional arrangement of movable elements (40) within the system (1). Embodiments of the dust collection system (1) of the invention includes: a housing (10) defining a cavity (50) therewithin, the housing (10) having a plurality of inlets (53) and at least one outlet (57) for gas; a plurality of movable elements (40) for opening and closing the inlets (53), the movable elements (40) being respectively provided corresponding to each of the inlets (53); a gas flow generating device (20) for generating a gas flow (A, S) from each of the inlets (53) to the outlet (57) during the opening operation of the movable elements (40); and a flow path control device (13) for controlling the flow paths of the gas flow (A, S).

Abstract: A device for filtering nanoparticulate matter below 300 nm in size from ambient air within a defined enclosed space comprises at least one filter medium containing at least one filter material, and a fan or blower, which blows or draws the air through the filter medium does so with sufficiently low air velocity in the filter medium that the air has a long residence time in the filter medium, during which time adhesive encounters between nanoparticulate matter and the solid phase of the filter material are highly probable. This air velocity is also being sufficiently low to ensure that, once adhesion has taken place, kinetic de-adhesion by the air flow is highly improbable. Such a device allows to keep the nanoparticle count inside the enclosed space kept below 5000/cc, equivalent to ‘natural woodland’, even though external levels may exceeded 200,000/cc: the removal of nanoparticles by cleaning making this <2.5% the external count.

Abstract: In a gas compressor, a cyclone block is configured to include a substantially cylindrical space into which a compressed gas is introduced to separate refrigeration oil from the gas. A pressure bypass is formed in the substantially cylindrical space defined by an outer cylindrical unit and an inner cylindrical unit to communicate with a discharge chamber having lower pressure than that of the substantially cylindrical space. The pressure bypass includes a pressure valve to open and close the pressure bypass in accordance with the internal pressure of the substantially cylindrical space having the pressure bypass. During a high speed operation of a compressor unit, the coolant gas including unseparated refrigeration oil is discharged from the pressure bypass.

Abstract: The invention relates to a particle separator for separating drill cuttings from an air flow, including a main separator (15) that comprises an air inlet (17) connectable to a suction nozzle, an air filter (19) arranged downstreams of said air inlet (17) and an air outlet (18) arranged downstreams of said air filter (19), the particle separator comprising means for generating an air flow, in the direction from said air inlet (17) to said air outlet (18). The particle separator also comprises means (41) for measuring a quantity of said air flow, and means for controlling the air flow generating means based on the measured quantity. The invention also relates to a drill rig comprising such a particle separator and a method for controlling such a particle separator.

Abstract: Systems and processes are provided for gas separation using high-speed permanent magnet variable-speed motors to accelerate and decelerate centrifugal compressors suitable for use in pressure swing adsorption (PSA) or vacuum pressure swing adsorption (VPSA) processes.

Abstract: A device for eliminating oil particles from the crankcase ventilation gas of an internal combustion engine. The device is located in the flow duct of the gas that runs from the crankcase to an induction tract of the engine. The device includes an oil separator in the form of an outlet for the gas with a deflection of the flow, causing the oil particles to be deposited on a baffle surface and thus to be eliminated from the crankcase ventilation gas flow. The device has an infeed cross-section, which lies upstream of the baffle surface when viewed from the flow direction of the crankcase ventilation gas, and which is sub-divided into several infeed sub-sections. The baffle surface is a solid surface that is devoid of perforations. The baffle surface is configured on a valve body, which lies downstream of the infeed sub-sections when viewed in the flow direction of the gas, and which is pre-tensioned by a force.

Abstract: The present invention is a method and system for recovering natural gas used to operate a diaphragm pump in a gas production unit (GPU) at or near a natural gas well. A system embodiment may include a back pressure valve installed on a natural gas line between an exhaust port of heat trace diaphragm pump and a vent to atmosphere, the back pressure valve configured for selectively blocking flow of natural gas to the vent. The system may further include a return line connected between the natural gas line and a burner system fuel line for redirecting the natural gas to a burner system. An embodiment of a method of recovering natural gas expelled from a heat trace diaphragm pump exhaust port may include preventing the natural gas from exhausting to atmosphere and redirecting the natural gas to a natural gas supply system.

Abstract: A filter module and method for facilitating rapid flow setting and/or cost-effective balancing of airflow through a plurality of filters is provided. In one embodiment, the filter module includes at least one port configured to provide a metric indicative of flow through the housing assembly. In various other embodiments, at least one port is utilized for sensing differential pressure across a flow restrictor, such as a damper assembly and/or a diffuser plate of the housing assembly, an orifice plate disposed in a collar or ductwork coupled to collar, and the like. In another aspect of the invention, a method for replacing an air filter is provided that includes the steps of replacing an air filter disposed in a filter housing assembly, and setting a damper position using a damper position indicator to return air flow through the filter to a predetermined rate.

Abstract: A trap device (18) for removing species from a gas stream drawn from an enclosure by a vacuum pump is described, the device (18) comprising a casing having an inlet (16) for receiving the gas stream, an outlet (20) for exhausting the gas stream from the casing, and first and second chambers (136, 138) each for receiving the gas stream from the inlet and conveying the gas stream to the outlet; means (170, 174) for selectively diverting the gas stream from the inlet to a selected one of the chambers; a first plurality of cartridges (32) each being removably insertable into the casing to provide a plurality of flow passages for gas passing through the first chamber; and a second plurality of cartridges (132) each being removably insertable into the casing to provide a plurality of flow passages for gas passing through the second chamber, each flow passage extending between an inlet and an outlet of a respective cartridge, each cartridge housing means for removing species from the gas passing therethrough as soli

Abstract: A dust collecting unit for a vacuum cleaner is provided. The dust collecting unit includes a filter assembly for filtering foreign objects coupled to a dust collecting cover which covers a dust collecting canister (320). The dust collecting canister receives and air foreign object mixture and accumulates the foreign objects therein. The filter assembly is disposed inside the dust collecting canister and filters out the foreign objects from the mixture. A damper assembly that selectively provides outside air to the inside of the dust collecting cover is positioned within the dust collecting cover. When pressure within the vacuum cleaner is increased due to an excessive amount of foreign objects accumulated in the canister, the damper assembly is activated to allow entry of outside air to relive the internal pressure and avoid a fan motor overload. In this manner, the damper assembly can quickly react to an increase in internal pressure and avoid damage to the fan motor cause by an overload.