Tecumseh Products Company

Robert L Terry

Arnold G Wyatt

Kent B Herrick

Alex Alvey

Lee W Marriott

John A Pasko

Rachel Weingrad

An integrated HVACR control and protection system includes a modular and reprogrammable design providing a plurality of possible combinations of power detection, voltage detection, run current detection, transient current detection, temperature detection, universal thermostat interface, peripheral or remote control, and local display and control. The control and protection system is capable of evaluating the relationship between real power used by an HVACR system compressor and other system operating parameters to detect problems early in the failure cycle, i.e., before a failure has progressed to requiring a system shutdown or causing damage to other components. Additionally, a control system and method provide sensorless detection of various HVACR system faults, such as, for example, loss of refrigerant or a refrigerant flow restriction, that impact the relationship between real power and current, voltage, temperature, or other operating parameters. Peripheral or remote control includes wired or wireless system monitoring and parameter programming using a personal digital assistant (PDA), for example utilizing IR communication between the PDA and the control and protection system.

Integrated HVACR control and protection system

A motor control system for a brushless and sensorless DC motor for driving a compressor, pump or other application, includes a protection and fault detection circuit for detecting a locked rotor and a rotor which has stopped because of lost rotor phase lock. The motor control system also includes an off-the-shelf motor control integrated circuit having an input for disabling power outputs to the motor phase coils. The protection and fault detection circuit uses a back EMF sampling circuit coupled to the motor phase coils and momentarily disables power to the motor phase coils, via the motor control integrated circuit input, to determine if the motor rotor is rotating. The system also monitors supply voltage, supply current, temperature, and motor speed limits to detect faults and protect system components.

Brushless and sensorless DC motor control system with locked and stopped rotor detection

A liquid level controller for a device having a liquid reservoir includes a control board and a reservoir assembly. The reservoir assembly is disposed within the reservoir and includes a liquid level sensor, which is electrically connected to the control circuit. The control board includes a control circuit and a pump. The control circuit has a control circuit and a resistive power supply to power the control circuit. The control circuit controls the pump in response to signals from the level sensor and includes a CMOS logic gate and a MOSFET transistor to switch the pump. The control circuit further includes a second resistive power supply connected to a relay which controls an alarm. The second power supply is activated by a transistor responsive to an alarm signal from the level sensor, and powers the relay only when the alarm signal is present.

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Tecumseh, MI, United States of America

Robert L Terry