Donald E. Knoop

An adaptive demand defrost and two-zone control and monitor system for refrigeration products

A defrost system that adapts to usage patterns and ambient conditions is described. The following parameters determine the interval between defrost operations: the amount and duration of door openings, the length of previous defrost operations, and the current freezer temperature. A two-temperature control system which allows the user to independently select freezer and fresh-food compartment temperatures is also discussed. The compressor run time and the air flow to the fresh-food compartment are controlled to achieve the desired results. These controls have been incorporated in a total control and monitor system which was recently introduced. The other features of this control are also briefly described. >

Microcomputers: A Technique for Electronic Control

The advent of microcomputers has provided an inexpensive, flexible, and sophisticated means for electronic control. This paper is an introduction to microcomputers. Typical applications are listed, and a comparison is made between minicomputers, microcomputers, and logic chips. Terminology and function of hardware components are defined. Key microcomputer selection parameters, with specifications of several microprocessors currently available, are presented. Finally, an example is presented to show programming techniques.

Automated Motor Testing Using a Minicomputer

A new approach to rapid automated performance testing of motors is presented in this paper. Specific application is made to brush motors (such as those used in vacuum cleaners) in order to illustrate the techniques on a motor which, because of its high speed and heating characteristics, is considered to be more difficult to test than other types of motors. The application of the technology described in this paper to other types of motors is straightforward.

Design of Appliance Control Systems Using Computer Simulation

The availability of computers and the advancement of control techniques have provided the necessary prerequisites for efficient investigation of appliance control systems by computer simulation. This paper discusses the general approach to simulation of appliance control systems, including discussions of determination of performance specifications, mathematic modeling of the appliance, simulation of the various control strategies, computer implementation, and evaluation of the results. Advantages and limitations of computer simulation are discussed. A specific application of a range temperature control system is utilized throughout the paper to demonstrate the application of the techniques and to show the value of computer simulation.