Abstract: The dynamoelectric machine has endwindings including a plurality of superposed conductor bars 22 and adjacent end turns 20. Rabbets 32 are formed along the undersides of the adjoining conductor bars and end turns to receive portions 34 of gussets 30, remaining portions 35 of the gussets projecting to one side of the joint. The conductor bars and end turns have grooves 38, 36 forming cooling passages with ports 42, 40 opening to one side of the joint short of the joint. The gusset 30 has a barrier 44 spaced from the joint and forms with the ports a cooling channel 46 between the ports for transporting cooling gas between the cooling gas channels of the conductor bars and end turns.

Abstract: A rotating electric machine includes a housing having a first inlet at one end for admitting ventilation air for cooling the machine, and a second inlet at the other end which also admits cooling air into the machine. A fan located at one end of the housing draws air into the housing through the first and second inlets, and forces it out of the housing through a single outlet located near one end of the housing. Air entering the second inlet passes through openings in the fan carrier, cooling isolated areas of the rotor, and flowing through the fan blades with the air which enters through the first inlet.

Abstract: A generator system having an auxiliary forced cooling-oil lubrication system in which a second pump for the fluid is driven in a self sustaining cooling and lubricating cycle, despite the failure of a primary pump action. The second pump can be electrically or mechanically driven to cause a reserve portion of the cooling-oil lubricant to recycle from a secondary reservoir. This secondary reservoir reserves a fluid capacity not circulated by gravity feed in a primary fluid circulating path, which normally returns the fluid to a primary reservoir. A primary pump circulates the fluid through a primary portion of a heat exchanger with an oil-to-fuel heat exchange transfer to sustain the cooling and lubricating functions of the generator system and the failure mode, second pump sustains cooling operations of a permanent magnet generator, despite the failure of a primary pump or loss of fluid circulating in the primary circulation path.

Abstract: Cooling of an alternator driven by an internal combustion engine wherein a field core of the alternator is composed of claw-type magnet poles and a cylindrical core such that an oil passage is formed in the regions where the cylindrical core and the rotor shaft oppose each other and where the cylindrical core and the claw-type magnetic poles oppose each other. The oil passage is communicated at its one end with an oil source outside the alternator so as to introduce an oil into the oil passage during operation of the alternator so that a centrifugal force is applied to the oil by the rotation of the rotary field core thereby spraying the oil in the form of vapor or mist onto the stator coil.

Abstract: A hollow shaft motor which has a ball screw shaft (24) passed therethrough and which drives the ball screw shaft (24) to rotate, wherein provision is made for flow paths (28, 30, 32) for passing compressed air for cooling purposes to one end of the motor so that the heat generated by the motor is not conducted to the ball screw shaft (24) through the ball nut (22) attached to one end of the cylindrical shaft (20) of the through type motor and engaged with the ball screw shaft.

Abstract: Electrical machines, such as electrical power generators, motors and the like, include an especially adapted cooling system for removing heat generated in the electromagnetic core during operation. The cooling system preferably includes a number of thermally conducting laminations interposed between predetermined ones of the core laminations that form the electromagnetic core. The thermally conducting laminations thereby establish a preferential solid path of thermal conductance so that heat generated in one region of the core may be conducted to another region of the core. Preferably, the thermally conducting laminations are formed of a nonmagnetic material. A thermal collector having at least comparable thermal conductivity properties as the thermally conducting laminations is provided at the othe region of the core so as to collect heat conducted thereto by the thermally conducting laminations. Coolant passageways are defined by the thermal collector so that circulation of a coolant fluid (e.g.

Abstract: A drive for workpiece spindle of a machine tool comprises a drive motor to be arranged on the free end of a workpiece spindle, a motor housing, a rotor to be mounted on the workpiece spindle and a stator arranged in the motor housing. The motor housing is connectable with a spindle box and has a motor cover. Cooling medium passages extend between the motor housing and the motor cover, between the rotor and the workpiece spindle and between the spindle box and the rotor.

Abstract: When an operation of a motor cannot be continued due to a large amount of heat generated when the motor is rotated at a high speed and under a high load, the motor is usually cooled by adopting a cooling structure using a coolant with a high cooling performance. It is, however, difficult to cast a casing with a complex channel, and the manufacturing costs are high. According to the present invention, through channels (15a, 15a) are formed along a central casing (10) of a motor casing consisting of a main central casing (10), a front end casing and a rear end casing (12, 14) when casting, and each through channel (15a, 15b) is communicated via communication holes (16a, 16b, 18a, 18b) drilled in the front end casing (12) and in the rear end casing (14), so that the whole of the casing can be fully cooled.

Abstract: A rotor for a vehicle dynamo includes a field coil bobbin (6) provided with ventilation slots (6a) and a heat conductive material (7) provided between the bobbin and the field cores, whereby the heat radiation from the field coil is increased. The bobbin is provided with a cylindrical portion and a pair of opposed flange portions which include at least one ventilation opening extending from the cylindrical portion into the flange portions.

Abstract: An adaptor assembly for a motor permits mounting to a pump to form a sump pump unit. A motor main frame has its end by end bearing frames. The adaptor assembly includes top and bottom plate adaptors formed of cast plastic or aluminum, and are separately inventoried for connection to a line of motors built for other applications as well as sump pumps. The bottom adaptor plate is secured to the end frame, with the motor shaft projecting concentrically of a hub extending from the plate. The hub telescopes over a tubular pedestal of the pump and has a collapsing collar for mounting the motor to the pump with the pump shaft and motor shaft coupled by a mating slot and projection. The plate is secured to the motor by suitable edge securement clips or by self tapping screws passing through a plate opening and threaded into a hole in the end frame. A top adaptor unit has a plate similarly secured to the top end of said motor.

Abstract: A ventilation cooling system for a dynamoelectric machine is disclosed, which provides improved cooling efficiency and reduction in windage loss. A first stream of cooling gas is directed into the spider of the machine and transversely through ventilation ducts in the rotor, across the gap, then through corresponding ducts in the stator. A further stream of cooling gas is drawn in between the spider and a shroud which extends inwardly transversely from the stator. This further stream is directed downwardly between the poles of the rotor and then transversely through the gap and stator in conjunction with the first stream.

Abstract: A superconducting rotating electric machine has superconducting rotor windings made from a high-temperature superconductor having a critical temperature of at least 78.degree. K. The rotor windings are cooled by a liquid coolant such as liquid nitrogen which is sprayed from the stator directly at the outer surface of the rotor.

Abstract: A scroll compressor comprises a compression mechanism comprising a combination of a fixed scroll and an orbiting scroll; a main shaft for driving the orbiting scroll; an electric motor rotor and stator for driving the shaft; a first bearing frame for supporting the orbiting scroll in the axial direction through a bearing; a second bearing frame for supporting the shaft in the radial direction through a bearing; a hermetic shell including the compression mechanism in an upper portion, the rotor and stator in a lower portion, and an suction pipe for inspiring a working fluid; and a dividing chamber arranged in the shell so as to communicate with the suction pipe and having efflux holes for directing the inspired working fluid to the compression mechanism in the upper portion, the stator and rotor in the lower portion, and an upper coil end of the stator placed in a position lateral to the chamber.

Abstract: A dual-face, internally-mounted cooling fan is provided in a dynamoelectric machine, e.g. an alternating current generator. The generator includes a ventilated housing supporting a stator assembly and a rotor assembly. The fan includes a divider disk having a plurality of blades provided on each surface and is mounted to rotate with the rotor assembly. As the fan is rotated, a plurality of separate air currents are drawn axially into the housing for cooling. The divider disk prohibits substantial mixing of currents drawn from opposite ends before they are radially expelled from the housing.

Abstract: A motor cooling system in which the stator (1) of a motor is coated with a coating layer (11), and a cooling liquid is applied to the projecting portions (10) of stator coils and to the side portions of the rotor (2) to cool the motor. The motor cooling system is advantageously applicable to a spindle motor for a machine tool.

Abstract: A starter-alternator of a vehicle of the type being disposed between a vehicle engine and a transmission case having a field pole member coupled to an engine crankshaft of the vehicle engine. Crow-poles are interspaced to form alternating N and S poles. A field winding is stationarily placed radially inside the crow-poles. A three phase stator winding is stationarily placed to surround the crow-poles, and a housing accommodates the stator-alternator elements therein and connects the vehicle engine and the transmission case. The housing is provided with an air passage for introducing fresh air into the housing so as to blow it toward the three phase stator winding in order to cool it, and an air outlet pipe discharges air inside the housing. In association with either one or both of the windings, a water pipe in communication with a water jacket of the vehicle engine is provided to circulate cold water therethrough.

Abstract: Apparatus and method for dissipating heat in a generator. A rotor having support wedges between each of its poles is mounted on a bored shaft in which a bored spindle having helical grooves along its outer diameter is fixed. A cooling medium is circulated through the bored shaft upon rotation of the shaft. The shaft has at least one outlet and one inlet through which the cooling medium can radially exit and return, respectively. Each of the support wedges has an inlet and an outlet between which a bore extends. In a preferred embodiment, a manifold is disposed about the bored shaft and mated to each of the support wedges so as to circulate the cooling medium from the bored shaft to the support wedges and back to the bored shaft, thereby dissipating heat from the generator rotor. In alternate embodiments more than one manifold is used to circulate the cooling medium through the support wedges.

Abstract: In an axial magnet bearing having an axial bearing disc, the axial bearing disc is constructed as a fan impeller for conveying a gaseous coolant. In this way, an effective cooling of the magnet bearing is achieved with a simple structure and, at the same time, it is possible to cool further heat-releasing elements, assemblies or units with the aid of a coolant flow promoted by the axial bearing disc.

Abstract: A commutator type, prior art dynamoelectric machine normally has an inlet for cooling air at the end of the machine remote from the commutator. The air flows from the inlet through axially extending passages in the rotor, outwardly through spaced radial ducts in the rotor, and into the air gap. Part of the air flows through the air gap to a collecting chamber at the commutator end of the machine to be discharged or exhausted. Part of the air flows radially outwards through interpolar spaces in the stator, through cooling ducts in the magnet frame to a peripheral passage which is connected to the collecting chamber at the commutator end. This invention provides a second collecting chamber at the drive end of the machine opposite the commutator end, communicating with the air gap and also with the peripheral passage at the drive end. Thus the air flow is divided after passing through the rotor and flows to the nearer collecting chamber providing a shorter flow path.

Abstract: A brushless alternator for an engine-generator set has a housing for mounting to the engine. Raised ribs define an internal bore of the housing, the bore having a constant diameter to mount the stator and the exciter field assembly, both of which have the same laminations. The ribs also define cooling air flow paths through the housing. A fan is mounted outside of the housing at the free end of the housing to draw air into the engine end, through the housing and out the free end.

Abstract: An A.C. alternator includes laminated stator core with an tubular frame formed from a plate member which is wrapped tightly about the core and with the opposed end edges of the frame plate welded to the core. The stator laminations having a square perimeter with the corners rounded with a radius of the final core diameter. The corner portion are further provided with a control welding notch and a plurality of circumferentially distributed openings. The laminations are stacked in rotated relation to form the core with a true constant diameter. Each lamination is rotated in the same direction of rotation for 120 degrees relative to the adjacent laminations. The multiple openings in the corner portions are constructed and arranged such that the rotating laminations aligned the similar openings and define a plurality of unobstructed axial cooling passages. The laminations are rotated to establish skewed elongated slots, central notches and air flow openings.

Abstract: There is provided a totally enclosed electric motor which is effectively cooled by means of an internal ventilation system and an external ventilation system. The internal ventilation system includes an internal fan driven by the rotor which forces internal ventilating air into and along an annular series of longitudinal internal ducts arranged adjacent to the internal cylindrical wall supporting the stator. The internal ventilating air leaving the internal ducts enters a brush compartment where the air is directed axially over the commutator and through the stator-rotor arrangement and back to the internal fan. The external ventilation system includes an external fan driven by the rotor which forces external ventilating air from the atmosphere into and along an annular series of longitudinal external ducts arranged radially outwardly from the series of internal ducts and into exhaust compartments at the far axial end of the motor.

Abstract: A gas cooling system for a bore pack exciter for a power generator in which high velocity, colder cooling gas is obtained from the region within the generator where the entering cooling gas is impelled by the generator fan, and means to direct part of that cooling gas from that flow through the bore pack exciter before return to the interior of the generator for recycling through the cooling unit.

Abstract: The rotor comprises a shaft from which two facing pole plates extend radially, each having a plurality of radial pole fingers whose ends are bent towards the other pole plate and each of which extends between two adjacent fingers of the other pole plate. An excitation winding is situated between the plates coaxial with the shaft. At least one axial ventilation duct is formed in the shaft from which branch radial ducts in correspondence with the pole plates, the ducts communicating with the corresponding ventilation passages provided in each pole plate, which open into recesses defined between pairs of adjacent pole fingers.

Abstract: A motor assembly for use in combination with an air handling system such as an automotive blower system for supplying cooling or heating air to a passenger compartment of an automobile. The assembly comprises a support member which is adapted to be mounted on the air handling system. Stationary and annular rotatable assemblies are mounted on one side of the support plate and a printed circuit board including a motor control circuit is mounted on the other side thereof. The stationary assembly has a plurality of winding stages adapted to be electrically energized to generate an electromagnetic field. The annular rotatable assembly has a plurality of permanent magnet elements surrounding the stationary assembly and is adapted to engage a squirrel cage fan for moving air in the air handling system.

Abstract: In a gas-cooled electric machine the cooling-gas supply and removal in the cavity between the laminated stator body and housing is arranged so that the heated cooling gases from the central section of the machine are supplied through separate cooling-gas lines to the ends of the machine and, consequently, to the coolers. In this manner, the individual volumetric flows through the individual zones (I, II, III) of the machine can be partitioned so that an equalization of the temperature level in the longitudinal direction of the machine is achieved.

Abstract: In a dynamoelectric machine which includes a rotor and a stator, an integral magnetic isolation and cooling system. A housing is disposed about the machine, the housing being fabricated of magnetically permeable material to define a flux path therethrough. A cooling jacket is sandwiched between the housing and the stator. The cooling jacket has coolant passages therein and is fabricated of non-magnetic material to isolate the flux path between the housing and the stator.

Abstract: A fan assembly that includes an impeller driven by an electric motor. The housing for the impeller has an air intake opening and a pressure-side connection for the discharge of air, with the pressure-side connection being provided with an air inlet opening that communicates with an air conduit that in turn leads to the electric motor housing. Air that flows through the air conduit is supplied at least to the region of the commutator of the electric motor. The electric motor housing is provided with an air outlet opening for receiving air that has been supplied to the electric motor housing via the air conduit, with this air outlet opening being in flow communication with an underpressure region of the impeller remote from the pressure-side connection of the impeller housing.

Abstract: A standard, predetermined phase sequence of the three-phase voltage output of an electrical power generator, as produced through conventional main leads in the generator lead box which interconnect three (3) generally, axially aligned pairs of connectors of first and second sets, is selectively reversible by the utilization of crossed main leads between two adjacent pairs of the connectors of the first and second sets. Each of the crossed main leads includes opposite end portions aligned with the diagonally-related and interconnected pair of connectors of the first and second sets, the end portions having corresponding bends therein for smoothly contouring and integrally joining the central portions thereof, and the central portions have complementary outward bends in at least the mutual crossing portions thereof to maintain a predetermined, minimum distance therebetween so as to satisfy voltage strike requirements.

Abstract: An eddy current power absorption unit has a particular cooling system which alleviates overheating of the unit and its individual components. Cooling conduits comprising a plurality of meandering paths, each including axially oriented flow lines, are disposed close to the heated components to uniformly remove heat therefrom. The flow velocities at the entrance and exit of the meandering flow paths are generally equal to one another.

Abstract: A synchronous machine having a rotor with a plurality of salient poles which are supported by a rotor rim. The rotor rim is arranged by means of a hollow annular device in mechanical connection with a rotor hub, cooling gas flowing into the annular device relatively close to the hub and leaving at the rotor rim, flowing through cooling ducts in the rotor and stator, through a cooler and out into a cooling gas space which includes a plurality of guide vanes arranged so that the cooling gas on its way from the cooler to the hollow, annular device passes through the guide vanes and is thus put in rotation around the axis of rotation of the rotor.

Abstract: In a self-ventilated electric motor such as utilized in a textile spinning mill machine, a fan cowling and cover plate are arranged to define a ventilating air flow pathway by respective support members which are disposed entirely outside the pathway to prevent accumulation of lint and debris on the support members.

Abstract: In gas-cooled electric machines with a closed cooling loop which is distributed over two heat exchangers, arranged on the upper or under side of the machine, only part of the circulating cooling gas is cooled so that the electric machine must be taken out of operation because of the danger of local ovewrheating. In order to overcome this, baffles are arranged adjacent to the heat exchangers so as to block the cooling gas on half the side of the opposite axial cooling gas passage regions of the heat exchangers, thus subdividing the cooling gas stream into two halves with opposite flow directions. The partial transfer of the cooling gas stream halves to the entire width of the axial cooling gas passage areas of the heat exchangers provides turbulence and a distribution of the cooling gas for uniform cooling also in the event of a failure of one heat exchanger.

Abstract: In a low capacity compressor, the shaft (20) of the drive motor carries a fan wheel (42) including a crank pin (46) formed integral therewith. The lower end of a connecting rod (62) is journalled on the crank pin (46). The portion of the fan wheel (42) opposing the crank pin (46) is formed with an arc shaped balancing rib (82) having an angular extension of 180.degree.. Precise balancing of the piston/fan wheel unit is obtained by cutting material from the initially oversized balancing rib (82) and/or cutting from the portion of the fan wheel (42) being opposed to the balancing rib (82) so that a balancing groove (102) is obtained.

Abstract: A cooling system for the parallel rings of an electrical generator. The system includes a coolant supply tank, supply and return lines, and a plurality of parallel, tubular liquid cooled conductor rings for conducting current generated in the stator windings of an electrical generator. Each ring has a coolant inlet, a coolant outlet, a central coolant passage and an adjustable flow controller which is selectively positionable so that its end portion lies inside the temperature coolant passage in the parallel rings to restrict the coolant flow for control purposes.

Abstract: A conductor bar in a dynamoelectric machine includes a coolant channel having a depressed portion passing under a gusset reinforcing a joint with an end turn. The end turn also includes a coolant channel with a depressed portion under the gusset and meeting the depressed portion in the conductor bar. The gusset includes a groove therein, generally congruent with the two depressed portions passing thereunder. Diagonal entry and exit portions on the underside of the gusset reduce flow turbulence of coolant entering and exiting the flow channel defined between the gusset and the two depressed portions. In a further embodiment of the invention, a diagonal portion joining the two depressed portions, matched with a congruent shape in the gusset, both reduces flow resistance and increases an area available for brazing the gusset in place.

Abstract: In an engine generator having a work generator arranged at the upper side of an engine of a vertical crank shaft type, the output shaft of the engine projects upwards from the engine crank case so as to be connected to the rotor of the work generator. And the stator is arranged so as to encircle the rotor and to be encircled by an air induction casing. A cooling fan of a centrifugal blower type is located at the upper end of the rotor shaft with the blades thereof directed to the side of the generator so as to supply a cooling air flowing upwards to both the interior and the exterior of the stator during operation.

Abstract: A hydraulic circuit branch of a cooling system in thermal contact with the stator winding of a hydraulic power generator is provided with a feed tube divided into two separate input tube sections. The downstream ends of the input tube sections are connected to respective multiplicities of subsidiary hydraulic circuit branches in the form of winding bars via a pair of semicircular manifolds. The current throughput through the winding bars is monitored by determining the difference between the rates of coolant flow through the approximately identical input tube sections. If the rates of coolant flow or throughputs in the input tube sections differ from one another by an amount which itself differs from a predetermined reference value by more than a preselected threshold, a warning signal is generated indicating that heat removal from the hydraulic power generator is being impaired.

Abstract: A cam locked air gap baffle assembly and method of installing same within a stator of a large, gas-cooled dynamoelectric machine utilizes a plurality of segmented baffles spaced by insulated tubes. Each baffle segment includes a wedge portion with a rotatable cam which serves to expand the wedge portion against the stator slot thereby locking it in place.

Abstract: A liquid-cooled motor having cooling liquid passages (26a, 26b, 26c) formed in the laminated core (16) of the stator (14). End plates (20, 22) are applied to the axially opposite end faces of the laminated core (16) of the stator (14), and a compressive force is applied through the end plates to the laminated core (16) by clamping the laminated core (16) with bolts (30) inserted through the end plates (20, 22) and the cooling liquid passages (26a, 26b) of the laminated core (16).

Abstract: A motor-generator set includes a rotatable central shaft and an AC rotor and a DC rotor being supported in tandem relationship along the shaft for rotation therewith. A liquid coolant flow path is defined in a series relationship through the shaft and rotors. A first portion of the serial liquid coolant flow path runs into and through a first single bore in one end portion of the shaft, a second portion of the serial flow path runs through the AC rotor, a third portion of the serial flow path runs through a middle portion of the shaft, a fourth portion of the serial path runs through the DC rotor, and a fifth portion of the serial flow path runs through and from an opposite end of the shaft.

Abstract: A ventilation system for end turn conductors spanning a pole face of a rotor of a dynamoelectric machine includes a first plurality of end turn conductors having a first plurality of longitudinally extending ducts having a respective coolant gas inlet disposed proximate the pole center and a respective coolant gas outlet disposed inboard of the end of the rotor body, and a second plurality of end turn conductors alternately stacked with, electrically insulated from and disposed in heat flow communication with the first plurality of end turn conductors. Each of the second plurality of end turn conductors includes a longitudinally extending gas coolant duct, having a coolant gas inlet proximate the winding corner and a coolant gas outlet inboard the end of the rotor body. The system is especially applicable to rotor windings wherein the conductors forming the end turns are not large enough to carry adjacent gas coolant ducts without compromising the structural and mechanical integrity of the winding.

Abstract: A motor cooling fan housing for a by-pass vacuum motor is presented. The fan housing includes a top plate connected to a cylindrical side portion. The top plate is characterized by a plurality of uniformly spaced tear-drop shaped slots therein. The slots provide for the entry of cooling air to the motor maintained therein. The slots are elongated and have a major axis which is non-collinear with the center point of the top plate of the housing.

Abstract: In a dynamoelectric machine having an annular stator core and a cylindrical rotor for concentric rotation therein, and defining a gap region between the rotor and the stator core, a baffle disposed in the gap region includes a shell member which circumferentially surrounds the rotor and includes a respective radial outwardly extending annular flange member at both its inner and outer axial end. An annular plate at the outer axial end abuts the axial outer flange and is radially adjustably secured to the stator. The axial inner flange comprises a flexible material, such as silicone rubber, and engages the stator in gas flow sealing relationship. An outer second passage disposed between the baffle and the stator is axially sealed off from the gap region by the flexible flange, thereby diverting gas in the outer passage to at least one coolant passage in the stator.

Abstract: Rotating rectifying device for excitation of a synchronous machine. The device includes an armature mounted on the machine shaft in a magnetic field with rotating coils connected to rectifier assemblies mounted on the inside flange surface of a support wheel, also mounted on the machine shaft. Each rectifier assembly has a first cooling body mounted on the inside flange surface, and a second cooling body that is resiliently spring biased with an outwardly facing surface against a disc-shaped semiconductor rectifier that rests with its other surface against the first cooling body. The second cooling body has parallel ribs that project into the circular space formed by the support wheel flange. In one version of the invention the second cooling body and the spring element is of circular construction.

Abstract: A charging generator for a vehicle has a cooling means for a stator coil and a bearing held at the front bracket side in addition to a cooling means for the rear bracket. A partition plate is provided in the front bracket to separate a window for cooling into an air intake window and an air discharge window, and air is sucked from the air intake window to be discharged through the air discharge window in which the front bearing and the front side coil are cooled.

Abstract: The control circuitry of a brushless blower motor is mounted on the stator of the motor and is cooled during operation of the blower by a portion of the air moved by the blower. A rotor cup member which covers and protects the control circuitry has at least a pair of radially displaced openings formed therein, and air is conveyed through the openings due to an air pressure differential therebetween created by the movement of air by the blower.

Abstract: In large dynamoelectric machines such as turbine generators, an air gap baffle assembly has eccentric rings to provide a differential thickness from top to bottom, so that before installation of an inner ring portion of the assembly, the rotor may be installed with greater clearance.

Abstract: Windage losses in a liquid cooled dynamoelectric machine having a stator 10 including an armature 14, a rotor 20 journalled for rotation about an axis within the armature 14, a pump 50, a sump 56 and a liquid flow path 24 within the rotor 20 are avoided through the use of a first transfer tube 58 connecting the pump 50 and one end 68 of the flow path along with a second transfer tube 92 coaxially surrounding the first transfer tube 58 and connected to the other flow path end 91 and to the sump 56.

Abstract: A portable generator in whose casing are housed an engine and a generator directly connected to and driven by the engine. A single cooling fan is provided at the connecting portion of a crankshaft in said engine and a revolving shaft in said generator to produce a unidirectional cooling air flowing from the generator side through the outside and inside of the generator to the engine side, as well as air intake and exit ports are provided in said casing side walls respectively in the vicinity of the side surface opposite to the engine of said generator and opposite to the generator of said engine, thus resulting in a high cooling efficiency of and an enhanced soundproof effect on the engine and generator as well as in a more compact generating system.