Abstract: A skew angle setting tool and method for assisting in orienting the skew pin of an apparatus having a mandrel for stacking rotor laminations for dynamoelectric machines is described. The skew pin is movable to have at least one predetermined angular orientation with respect to the axis of the mandrel. The tool includes a first member configured to be positioned in a generally coextensive relation with the mandrel and has at least one location thereon corresponding to a preselected rotor lamination stack height, and a second member disposed in predetermined relation to the location on the first member corresponding to the preselected rotor lamination stack height. The skew pin is positionable in registration with one or more locations on the second member to orient the skew pin in corresponding angular orientations with respect to the mandrel axis.

Abstract: A motor includes a stationary assembly and a rotatable assembly in magnetic coupling relation thereto. The stationary assembly includes a winding, the rotation of the rotatable assembly inducing a back EMF in the winding. A power supply for supplying a voltage across the winding drives a current through the winding. A back EMF sensor connected to the winding generates a back EMF signal representative of the back EMF induced in the winding during periods of time when the voltage is being supplied across the winding. An inverter connected between the power supply and the winding commutates the winding as a function of the back EMF signal, whereby the rotatable assembly rotates. A method of operating the motor and a control circuit for the motor employ the back emf induced in the winding during periods when the voltage is being applied to the winding by the power supply.

Abstract: A mounting clip for securing a motor protector to the stator of an electric motor is described. In one embodiment, the mounting clip includes a protector holding region formed by a base portion, a back portion, arm portions, and a retaining member. The protector is positioned within the protector holding region. The base of the mounting clip seats upon the uppermost, or outermost, lamination of the lamination stack forming the motor stator and includes one or more fingers sized for insertion between adjacent stator winding gaps. The mounting clip is maintained in position by the friction fit between the clip fingers, the stator windings and insulation.

Abstract: Systems and methods for controlling a draft inducer for use with a furnace. The draft inducer includes a fan for inducing a draft in the furnace combustion chamber that causes a pressure drop across a heat exchanger assembly for moving exhaust combustion chamber gases. The heat exchanger assembly has a plurality of heat exchanger elements which determine furnace capacity wherein the pressure drop across the heat exchanger assembly is affected by the furnace capacity. A motor drives the fan in response to a motor control signal and a memory stores information defining a relationship between motor speed, motor torque and parameters defining motor operation. A processor determines the speed and torque of the motor and retrieves from the memory the parameters corresponding to the determined motor speed and motor torque. The processor is responsive to the retrieved parameters for defining at least one set of speed/torque curves corresponding to a desired pressure drop across the heat exchanger assembly.

Abstract: Draft inducer systems and methods for use with a furnace. A motor drives a fan in response to a motor control signal for inducing a draft which is a function of motor speed and motor torque. A processor defines a speed/torque operating curve having a minimum desired speed and a maximum desired speed between which the speed/torque operating curve is coincident with a pressure curve corresponding to a desired pressure drop across the furnace heat exchanger assembly caused by the draft induced by the fan. The speed/torque operating curve, for a given speed above the maximum desired speed, defines a torque less than the torque defined by the pressure curve for the given speed.

Abstract: A bearing assembly including a bearing member with a passageway therethrough at least in part defining a cylindrical journaling surface having a central axis and a preselected axial length is described. A partial circumferential or spherical surface on at least a part of a peripheral portion of the bearing member extends generally coaxial about the cylindrical journaling surface. A bearing seat supports the bearing member at a generally circular line of engagement defining an imaginary plane extending generally perpendicular to the central axis through the mid-point of the preselected axial length of the cylindrical journaling surface.

Abstract: Systems and methods for controlling a draft inducer for use with a furnace. The draft inducer includes a motor for driving a fan for inducing a draft in the furnace that causes a pressure drop across the heat exchanger of the furnace. A memory stores information including a table of predefined speed/torque values for defining a set of speed/torque curves for operating the motor. A pressure switch provides a pressure signal representative of a reference pressure across the heat exchanger and a processor determines the speed and torque of the motor when the pressure drop corresponds to the reference pressure. In response to the determined motor speed and motor torque, the processor retrieves a parameter defining at least one delta value from the memory. The processor adapts the predefined speed/torque values as a function of the delta value thereby to define the speed/torque curves corresponding to a desired pressure drop.

Abstract: A single phase motor system and method for preventing excessive circulating currents in the motor. The motor has a power supply link including power switches responsive to a motor control signal for connecting the motor winding to a power supply in alternating on and off intervals. A current sensing circuit senses current in the power supply link during the on intervals. A current regulation circuit generates a current regulation signal representative of the difference between the sensed current and a peak regulated current level that is a function of desired motor speed and/or torque. An overcurrent circuit generates an overcurrent signal in response to the sensed current exceeding a maximum current level greater than the peak regulated current level. The motor also has a control circuit responsive to the current regulation signal for generating the motor control signal thereby to regulate current in the winding and control the motor speed and/or torque.

Abstract: Methods and apparatus for controlling energization of an appliance motor are described. The apparatus, in one embodiment, may include a condition responsive switch secured within an appliance motor casing to control the energization of the appliance motor windings. In one mode of operation, the condition responsive switch substantially prevents energization of the motor windings if at least one attachment has not been substantially properly secured to the appliance, and the switch substantially properly secured to the appliance.

Abstract: A dynamoelectric machine constructed for speed and accuracy of manufacturing has a stator core constructed of 90.degree. symmetrical stator laminations and the windings have differing numbers of poles which overlap in slots of the stator core are wound of the core formed by the laminations in unique fashion. The rotor bars of the machine are skewed to optimize performance of the machine when in the form of a single phase induction motor. Magnet wire leads of the windings are connected directly to terminals on a plug and terminal assembly which is formed for positive location on an end frame of the machine without welding or other fastening to the end frame. The end frames of the machine and stator laminations forming the stator core are formed so as to increase the precision of the final position of the stator relative to the rotor assembly of the dynamoelectric machine. The end frames are constructed for grounding without the use of fasteners or wire.

Abstract: An apparatus for driving a fan as part of a refrigerator is disclosed. The refrigerator has a compartment, a compressor, an evaporator and a condenser. A temperature sensor is positioned in association with the compartment and outputs a sensed temperature signal as a function of the temperature in the compartment. The apparatus includes a reference circuit which provides a desired temperature signal representative of a desired temperature. A comparator compares the desired temperature signal and the sensed temperature signal and generates a cool signal when the compartment temperature is above the desired temperature. A timer times out an elapsed period of time commencing when the cool signal is generated. A motor includes a rotatable assembly in driving relation to the fan. A control circuit controls operation of the motor as a function of the sensed temperature signal and the elapsed period. Related apparatus and methods are also disclosed.

Abstract: A motor having a differential phase back EMF sensing circuit for sensing rotor position includes a stationary assembly with at least three windings. The rotation of the rotor induces a back EMF in the windings. A control circuit energizes each of the windings with a current according to a preselected sequence. A switch network is coupled to the windings and provides two back EMF signals as a function of the back EMF induced in two of the windings when the control circuit is energizing the third winding. A signal processor is coupled to the switch network and produces a difference signal representative of a difference between the two back EMF signals. An integrator integrates the difference signal to produce an integrated difference signal. The motor includes a reference signal generator which produces a reference signal and a comparator which produces a trigger signal when the integrated difference signal exceeds the reference signal.

Abstract: A dynamoelectric machine constructed for speed and accuracy of manufacturing has a stator core constructed of 90.degree. symmetrical stator laminations and the windings have differing numbers of poles which overlap in slots of the stator core are wound of the core formed by the laminations in unique fashion. The rotor bars of the machine are skewed to optimize performance of the machine when in the form of a single phase induction motor. Magnet wire leads of the windings are connected directly to terminals on a plug and terminal assembly which is formed for positive location on an end frame of the machine without welding or other fastening to the end frame. The end frames of the machine and stator laminations forming the stator core are formed so as to increase the precision of the final position of the stator relative to the rotor assembly of the dynamoelectric machine. The end frames are constructed for grounding without the use of fasteners or wire.

Abstract: A tandem press system for the high speed manufacture of rotor cores and stator cores of electric motors. The tandem press system includes a rotor press and a stator press arranged in series for stamping out laminations from a web of stock material and pre-assembling them into rotor cores and stator cores, respectively. Structure is provided between the rotor and stator press to maintain control of the web and provide a substantial barrier to transmission of vibrations in the web to the stator press. The rotor and stator presses are capable of shifting from stamping one type of lamination to stamping another type of lamination without any interruption in the operation of the presses.

Abstract: A dynamoelectric machine having a stator housing or frame made by a lost foam process utilizing a unitary single-piece vaporizable pattern. The stator housing may be made from a molten metal such as cast iron or aluminum, and has an annular wall having integral outwardly extending longitudinal cooling fins, mounting foots pads and a conduit box support pad. The lost foam process enables the cooling fins to have a greater effective cooling fin height to housing diameter ratio and greater effective cooling fin height to housing annular wall thickness ratio than obtained with prior sand casting processes. The greater height fins provide increased strength and rigidity for the annular wall which can be made radially thinner than prior stator housing or frames of similar size. Substantial savings in material and labor are realized by the stator housing.

Abstract: An apparatus adapted to be connected to a power source, the apparatus for driving a rotatable component. A motor has a stationary assembly and a rotatable assembly in magnetic coupling relation to the stationary assembly, the rotatable assembly in driving relation to the rotatable component, the stationary assembly including windings adapted to be energized by the power source to produce an electromagnetic field for rotating the rotatable assembly, the windings having a maximum desired operating temperature and a predetermined minimum desired temperature rise. A heater is in heat exchange relationship to an outer surface of the windings, the heater adapted to be connected to the power source at least when the motor windings are not energized to generate heat transferred to the windings to increase the temperature of the windings. An optional thermostat may be connected in series between the heater and the power source.

Abstract: A laundry machine having an electronically commutated motor which includes a plurality of salient pole pieces disposed on preselected pitch axes so as to extend generally outwardly from an outer circumferential surface of a yoke section, with base sections of the salient pole pieces secured to the yoke section against displacement therefrom at least generally adjacent the outer circumferential surface.

Abstract: Systems and methods for controlling a draft inducer for use with a furnace. The draft inducer includes a fan for moving combustion chamber gases for inducing a draft in the furnace combustion chamber that causes a pressure drop across a heat exchanger. The density of the gases flowing across the heat exchanger and the fan differs from a first operating state of the furnace to a second operating state of the furnace. A motor drives the fan in response to a motor control signal so that different motor speeds result as a function of the density of the gases flowing across the fan. A control circuit generates the motor control signal as a function of a first set of speed/torque curves until a speed signal indicates that the motor has reached a predetermined speed. After the speed signal indicates that the motor has reached the predetermined speed, the control circuit generates the motor control signal as a function of a second set of speed/torque curves.

Abstract: Disclosed is an improvement to the stability of D.C. motor brushes mounted in brush boxes with wings is improved by angling the wings toward the commutator such that the brush spring contacts the brush at one or more points intermediate the ends of the brush. Improved cooling is provided by utilizing an end plate with apertures and a brush plate which in combination with the commutator, provides a brush plate aperture for cooling air flow. In a preferred embodiment, speed variations of the motor can be achieved by selectively disconnecting one or more brushes in a four brush embodiment reducing the torque and rotating speed of the motor. In a preferred embodiment, the use of a diode to interconnect same polarity brushes permits a speed change to be accomplished by selectively connecting one or the other end of the diode.

Abstract: A structured product family of dynamoelectric machines for use in a plurality of applications has a frame with a closed end, and a set of permanent magnets is adhesively secured within the frame. An armature disposed in the frame for interaction with the permanent magnets includes a shaft, a core having a set of winding receiving slots therein, and a commutator. During manufacturing and assembly, stress on the motor shaft and commutator is minimized. A brush plate is associated with the frame for locating a set of brushes relative to the commutator, and an end shield is secured to the frame opposite its closed end. At least one freely aligning bearing assembly disposed in the end shield for freely aligning the shaft and including a bearing and a retainer having predetermined conditions preset with the retainer being adhesively secured to the end shield. A bracket is adhesively secured to the frame for connecting the dynamoelectric machine in anyone of the applications; and a novel brush assembly is provided.