Abstract: A method of fabricating a potentiometer in which conductive stampings are cut to be both the connector pins and the substrate of the potentiometer. In the region where the potentiometer is desired, an insulating layer covers the surface of the stamping. The insulating layer can be the same material as the solder mask, and electrically isolates the connector pins from the resistive area. Next, carbon trace is screen-printed over the insulating layer where the potentiometer is desired, and oven-cured. This subassembly is then placed into a housing of plastic or another insulating material. Last, the feedback and ground pins are assembled into the plastic housing. The ground pin is laid on top of the end of the carbon trace to make an electrical connection to the resistive trace.

Abstract: A system and method for auto-addressing devices on a multiplexing bus in which a plurality of devices are arranged in series, with each having a bus in and bus out. During an initial evaluation, and beginning with a low bus in, each device inverts the incoming signal so that a device with a low bus in has a high bus out. During a second evaluation, the high or low state of the bus in is inverted only if the bus out in the first evaluation was high. Similarly, during subsequent evaluations, the high or low state of the bus in is inverted only if the bus out state of all previous evaluations was high. Ultimately, only one device will have a high bus out, with all bus out states from previous evaluations also having been high, at which point all addresses are fully decoded.

Abstract: A stall detection circuit and method for a stepper motor. The circuit has an H-bridge configuration with an additional circuit pathway to ground being connected at a point between two center windings. During the transition between step sequences, the circuit employs a monitoring phase in which the previously active low side driver is turned off such that current passes through only the first winding and then is diverted to ground via the additional pathway. While the phase voltage is thus momentarily extinguished, the second coil is used to monitor the motor's back EMF, from which it can be determined whether the rotor is in a normal running mode, a stall, or a reverse condition.

Abstract: An actuator position control system for brush-type DC motors. The system includes a sensor, amplifier or differentiator, central control unit (microprocessor), and motor driver. The system utilizes the differential signal di/dt to indicate the falling edges of commutation spikes in the motor current profile. In a first embodiment, an inductor is selected as the signal sensor, because voltage drops across the inductor are directly proportional to di/dt. The voltage drop, L(di/dt), across the inductive sensor is input to the amplifier, amplified, and then sent to the microprocessor. In a second embodiment, a sensing resistor and a differentiator are substituted for the inductive sensor and amplifier, respectively. The microprocessor reads the output pulses from the amplifier or differentiator and compares the pulse count to an input command signal. The microprocessor then sends shaft position control information to the motor driver.

Abstract: A mechanically-commutated DC motor has a mechanical commutation system and an “inside-out” configuration, in which the stator assembly comprises the windings and the rotor assembly comprises the permanent magnet. The motor includes a rotor assembly, a stator assembly, a plurality of terminating conductive pads, and positive and negative stationary power supply terminals. The stator assembly includes a plurality of lamination stacks positioned around a central aperture and a plurality of copper coils, each coil being wound around one of the lamination stacks. The rotor assembly includes a rotor body with a permanent magnet ring and a non-conductive timing cam integrated into one face of the rotor body. The permanent magnet ring is radially magnetized in an alternating polarity pattern with at least one pair of poles. The mechanical commutation system comprises the timing cam integrated into the rotor assembly, the power supply terminals, and the conductive pads.

Abstract: An actuator position control system for brush-type DC motors. The system includes a sensor, amplifier or differentiator, central control unit (microprocessor), and motor driver. The system utilizes the differential signal di/dt to indicate the falling edges of commutation spikes in the motor current profile. In a first embodiment, an inductor is selected as the signal sensor, because voltage drops across the inductor are directly proportional to di/dt. The voltage drop, L(di/dt), across the inductive sensor is input to the amplifier, amplified, and then sent to the microprocessor. In a second embodiment, a sensing resistor and a differentiator are substituted for the inductive sensor and amplifier, respectively. The microprocessor reads the output pulses from the amplifier or differentiator and compares the pulse count to an input command signal. The microprocessor then sends shaft position control information to the motor driver.

Abstract: An actuator position control system for brush-type DC motors. The system includes a sensing inductor, amplifier, central control unit (microprocessor), and motor driver. The system utilizes the differential signal di/dt to indicate the falling edges of commutation spikes in the motor current profile. An inductor is selected as the signal sensor, because voltage drops across the inductor are directly proportional to di/dt. The voltage drop, L(di/dt), across the inductive sensor is input to the amplifier, amplified, and then sent to the microprocessor. The microprocessor reads the output pulses from the amplifier and compares the pulse count to an input command signal. The microprocessor then sends shaft position control information to the motor driver.

Abstract: An actuator housing provides a low-cost method of achieving electrical connection to the motor terminals of a DC motor in a two position HVAC actuator. The connector configuration interfacing with a controller or power supply is easily changed by making the connector a modular connector, providing an effective fluid ingress prevention. The modular connector design is fixed from the connector flange inward into a housing, and is flexible outward with respect to its pin configuration and shroud shape. This design allows different connector configurations to be utilized with minimal tooling investment. A capacitor can also be inserted and crimped to the connector pin stampings, prior to being over-molded, to provide EMI filtering.