Abstract: An apparatus for evacuating liquid condensation from pipe systems which is particularly applicable to exhaust pipe systems in high efficiency furnaces. The apparatus forms a junction sleeve between two pipes and has drainage channels which prevent condensate liquid from flowing from one pipe into the other pipe. A thermoplastic rubber composition of the apparatus dampens noise and vibration in the pipe system. External grooves provide locating features for mounting clamps.

Abstract: A single piece impeller that includes an integrally formed hub, back plate, inlet support ring and a plurality of impeller blades. The impeller blades each extend radially from an inner, leading edge to an outer, trailing edge. An extended portion of each impeller blade extends past the outer edge surface of the back plate such that the extended portion is not support along a lower edge surface. The top edge surface of the extended portion of each impeller blade is integrally formed with the support ring. The support ring provides support for each of the impeller blades and is sized to allow the single piece impeller to be removed from a mold.

Abstract: A non-dilution air water heater blower for use in expelling exhaust gases from a water heater. The water heater blower includes a one piece blower housing defined by an outer wall having an upper section and a lower section. An inlet plate is positioned between the upper section and the lower section of the blower housing to define an upper chamber and a lower chamber. The lower chamber of the blower housing surrounds the exhaust flue from the water heater. A blower motor is attached to the outside surface of the blower housing. A rotating impeller coupled to the blower motor and positioned in the upper chamber draws exhaust gases from the water heater into the lower chamber through an inlet aperture formed in the inlet plate and out of an exhaust outlet formed in the upper chamber.

Abstract: The present invention is organized about the concept of providing an improved pawl brake assembly for use in electromechanical devices such as all electric motors or solenoids. For example, the improved pawl brake assembly may be used for braking the rotor assembly upon de-energization of the motor. The pawl brake assembly comprises a pawl arm and a brake portion. The pawl brake assembly employs electromagnetic principles to reduce the noise and metal fatigue caused by the undesired excess vibrational motion of a pawl arm wen a motor is energized. The novel use of a magnet disposed upon the pawl arm of a pawl brake assembly provides a single, elegant, and inexpensive solution to the identified noise and metal fatigue problems.

Abstract: An apparatus and method for controlling a motor/blower system to provide a constant fluid flow by iteratively loading revised stator frequency values and stator voltage values to a variable frequency drive. Target DC bus current values corresponding to constant fluid flow rates are predetermined and stored as a function of the desired fluid flow rate, the operating frequency, and system specific constants or calculated by the controller as a function thereof during system operation. Actual DC bus current is measured with a current sensor and compared with the target DC bus current. Operating frequency is estimated using a PI controller based on the difference between measured and target DC bus current values. Operating voltage values corresponding to operating frequencies and system specific constants are predetermined and stored in memory or calculated by the controller during system operation. An updated target DC bus current, operating frequency and operating voltage are determined upon each iteration.

Abstract: A furnace blower housing that can be flush mounted to a furnace and includes an integrally formed round exhaust outlet. The blower housing is formed from two separate housing members joined to each other. The blower housing includes an impeller cavity that encompasses a rotating impeller that directs the exhaust gases out of a rectangular outlet. An integrally formed transition section extends from the rectangular outlet to a circular exhaust outlet. The transition section is formed by a bottom half integrally formed with the first housing member and a top half integrally formed with the top housing member. The exhaust outlet is offset from the back plate of the blower housing such that the blower housing can be flush mounted to a furnace.

Abstract: An apparatus and method for controlling a brushless direct current motor having a pulse width modulated variable frequency drive in a blower system so that the blower system provides a specific fluid flow. A start-up program causes the motor to ramp up to approximately a predetermined steady state speed. A required blower torque is calculated by operating on a table of blower constants, a selected flow rate and a motor speed which is read from a commutation Hall sensor in the motor. A developed motor torque is calculated by operating on a table of motor specific constants, a modulation index and the motor speed taken from the commutation Hall sensor. The calculated required blower torque is repeatedly compared with the calculated developed motor torque. The modulation index to the pulse width modulated variable frequency drive is modified to force the developed motor torque to converge with the required blower torque in a steady state.

Abstract: An apparatus and method for controlling an induction motor having a variable frequency drive in a blower system so that the blower system provides a specific fluid flow. A start-up program causes the motor to ramp up to approximately a predetermined steady state speed. A required blower torque is calculated by operating on a table of blower constants, a selected flow rate and a motor speed which is read from a speed sensor in the motor/blower system. A developed motor torque is calculated by operating on a table of motor specific constants, a voltage-frequency index and the motor speed taken from the speed sensor. The calculated required blower torque is repeatedly compared with the calculated developed motor torque. The voltage-frequency index to the variable frequency drive is modified to force the developed motor torque to converge with the required blower torque in a steady state.

Abstract: An apparatus and method for controlling an induction motor having a variable frequency drive in a blower system so that the blower system provides a specific fluid flow. A start-up program causes the motor to ramp up to approximately a predetermined steady state speed. A required blower torque is calculated by operating on a table of blower constants, a selected flow rate and a motor speed. The motor speed is calculated by operating on a table of motor specific constants, a voltage-frequency index and a measured direct current bus current. A developed motor torque is calculated by operating on a table of motor specific constants, a voltage-frequency index and the calculated motor speed. The calculated required blower torque is repeatedly compared with the calculated developed motor torque. The voltage-frequency index to the variable frequency drive is modified to force the developed motor torque to converge with the required blower torque in a steady state.

Abstract: A brushless dc motor assembly including control electronics for allowing variable speed, user-controlled motor operation. The control electronics are connected to a control board which is mounted directly to the motor bearing bracket. Hall effect devices for providing rotor rotational position information to the electronics are connected directly to the control board and extend therefrom to a position adjacent the rotor. The electronics control current through the stator winding through a MOSFET H-bridge circuit in dependence of feedback signals from the hall effect devices, a user-controlled enable signal, a motor winding current limit signal, and an under voltage signal.

Abstract: A blower is disclosed which has a housing that provides a means for drawing dilution air into a combined motor and impeller housing. The dilution air is drawn into a first chamber which houses the blower motor and is then drawn into the impeller chamber where the dilution air mixes with hot exhaust gases from a hot water heater to which the blower is attached. Apertures on a back plate of the impeller provide fluid communication between the motor chamber and the impeller chamber. The housing has walls which extend beyond a housing cover to form a skirt so that the attachment of the blower to a water heater top results in a third chamber being formed within which the water heat flue is situated. The combination of the skirt section, the housing cover and the top of the hot water heater comprise the third chamber which has at least one slot provided therein for drawing dilution air into the third chamber where the dilution air is mixed with the exhaust gases exiting the water heater flue.

Abstract: An electric motor design and method useful to reduce noise/vibration generated by a rotor/shaft assembly is provided whereby the motor has a stator which has an axial length and a rotor which has an axial length less than the axial length of the stator such that when the rotor rotates within the motor, the rotor is axially fixed by a stator field.

Abstract: A brushless dc motor assembly including control electronics for allowing variable speed, user-controlled motor operation. The control electronics are connected to a control board which is mounted directly to the motor bearing bracket. Hall effect devices for providing rotor rotational position information to the electronics are connected directly to the control board and extend therefrom to a position adjacent the rotor. The electronics control current through the stator winding through a MOSFET H-bridge circuit in dependence of feedback signals from the hall effect devices, a user-controlled enable signal, a motor winding current limit signal, and an under voltage signal.

Abstract: A blower housing body is disclosed comprising a housing body and housing cover. The housing body and housing cover are provided with mating surfaces that provide the ability to releasably lock the housing cover to the housing body to allow ease of disassembly for basic maintenance and re-assembly for continued use. The locking mechanism is accomplished by a ridge formed on the top of a side wall of the housing body and a corresponding channel in the housing cover.

Abstract: An electric motor input circuit including a leadless capacitor which reliably and efficiently provides the highest possible level of RFI suppression and the greatest reduction in conducted voltage transients. The assembly includes a capacitor having no solid lead wires and no epoxy coating which is snap-fit into the motor power circuit so that one of the capacitor plates is in pressing engagement with one of the input terminals and the other of the capacitor plates is in pressing engagement with a conducting tab. The conducting tab is formed on the other of the input terminals, and the capacitor is, therefore, connected between the terminals without the use of solid capacitor leads.

Abstract: This invention features a condensate drain that drains condensate from an impeller housing as well as an impeller housing having such a drain. This condensate drain is configured so as to allow the condensate from the exhaust to be continuously drained from the housing while the impeller is or is not operating. Preferably, the impeller housing includes a housing shell having an aperture in fluid communication with the housing interior. A top portion of the aperture extends above an interior surface of the housing shell to minimize the venturi effect of air flowing by the aperture responsive to rotation of the impeller. The interior surface of the housing further includes a dished region proximate the aperture, where the bottom of the dished region is arranged to correspond with a bottom edge of the aperture.

Abstract: A noise cancellation device for a centrifugal blower comprises, in a first embodiment, a rod mounted in the output of a blower and generally axially parallel to the impeller so that as the impeller rotates, the blades of the impeller sweep past the rod much as in the manner that the blades sweep past the cutoff section of the blower output. The rod is positioned a specified distance away from the cutoff such that it generates a tone which interferes with the pure tone otherwise generated by the impeller blades sweeping past the cutoff in an out of phase condition to thereby eliminate the pure tone or "spike" normally experienced at a fundamental frequency and harmonics thereof. In a second embodiment, a nose-like projection extends inwardly from a sidewall of said blower housing and is positioned substantially in the same position as the rod of the first embodiment. The nose-like projection may be integrally formed as part of the blower housing.

Abstract: A noise cancellation device for a centrifugal blower comprises a rod mounted in the output of a blower and generally axially parallel to the impeller so that as the impeller rotates, the blades of the impeller sweep past the rod much as in the manner that the blades sweep past the cutoff section of the blower outlet. The rod is positioned a specified distance away the cutoff such that it generates a tone which interferes with the pure tone otherwise generated by the impeller blades sweeping past the cutoff in an out of phase condition to thereby eliminate the pure tone or "spike" normally experienced at a fundamental frequency and harmonics thereof.

Abstract: An electronic safety circuit for a portable gas heater includes a transformer and half wave rectifier connected in parallel with a fan motor for charging a capacitor, and a solid state switching circuit, which may be either a pair of cascaded transistors, an SCR, or a Darlington switch, for applying a reverse polarity voltage across the solenoid of a solenoid operated gas valve to immediately turn off the gas valve in the event of loss of power to the combustion fan motor. The electronic safety circuit may be conveniently mounted on a PC board and enclosed in the combustion fan motor.

Abstract: An electromagnetic contactor comprising a housing, the housing being adapted to receive internally thereof a stationary armature, a coil subassembly, return springs, and a block subassembly, the block subassembly comprising a block adapted to receive terminals and a carrier subassembly, the carrier subassembly comprising a carrier member adapted to receive and retain a movable armature, the housing having internally thereof a plurality of detents adapted to be overridden by the block subassembly and to snap over exposed surfaces of the block subassembly to lock the block subassembly, the stationary armature, and the coil assembly in the housing, whereby to complete assembly of the contactor without fasteners; and a method for making the contactor.