US 5,303,560 A · Method and apparatus for monitoring and controlling the operation of a refrigeration unit

Abstract

Methods and apparatus for monitoring and controlling the operation of a refrigeration unit in a manner which eliminates the need for circuit breakers and fuses in control circuits which are instrumental in selecting and changing the operational mode of the refrigeration unit. When a need to change to a different operating mode is detected, a controller energizes a control device associated with the different operating mode and quickly determines if the current draw is within an acceptable range. If the current draw is within an acceptable range or window, the controller initiates the requested different operating mode. If the current draw is not within the acceptable range, the controller generates an appropriate alarm and different courses of action are decided upon which depend upon whether the current draw is above or below the limits of the acceptable range, the nature of the requested operating mode, and the desired temperature of a space conditioned by the refrigeration unit.

Claims30

Dependent claims

A method of operating and monitoring a refrigeration unit which includes electrical control having a voltage source, a control circuit which includes a plurality of control devices, and a controller which selectively energizes and de-energizes the control devices via a plurality of control outputs, comprising the steps of:

determining if the refrigeration unit is running,
de-energizing the control outputs of the controller when the determining step finds the refrigeration unit is not running,
measuring the magnitude of the current draw of the control circuit from the voltage source with the control outputs of the controller de-energized,
providing a current reference value which indicates the maximum allowable current draw with the control outputs of the controller de-energized,
comparing the measured current draw with the reference value, and
providing an alarm which indicates the controller should be checked when the measured current draw exceeds the reference value.

3 more elements

A method of operating and monitoring a refrigeration unit operable in a plurality of different selectable operating modes, including electrical control having a voltage source, a control circuit which includes a plurality of control devices associated with the plurality of operating modes, and a controller which selectively energizes and de-energizes the control devices via a plurality of control outputs, comprising the steps of:

determining when a change from one operating mode to a different operating mode is required,
energizing the control device associated with the different operating mode,
measuring the magnitude of the current draw of the control circuit after the control device of the different operating mode is energized,
providing a current draw window having upper and lower limits which define an allowable current draw range for the control circuit with the control device of the different operating mode energized,
comparing the measured current draw with the current draw window, and
initiating the different operating mode when the measured current draw is within the current draw window.

3 more elements

Control apparatus for monitoring and controlling the operation of a refrigeration unit, with the electrical control apparatus including a voltage source, a control circuit which includes a plurality of control devices, and a controller which selectively activates the control devices via a plurality of control outputs, comprising:

a current shunt disposed between the voltage source and the control circuit,
means determining if the refrigeration unit is operating,
means de-energizing the control outputs of the controller when the refrigeration unit is not operating,
means measuring the magnitude of the current draw of the control circuit with the control outputs of the controller de-energized,
means providing a current reference value which indicates the maximum allowable current draw with the control outputs of the controller de-energized,
means comparing the measured current draw with the reference value, and
means providing an alarm which indicates the controller should be checked when the measured current draw exceeds the reference value.

4 more elements

Dependencies are inferred from the claim text.

Method and apparatus for monitoring and controlling the operation of a refrigeration unit

Life of this patent

Method and apparatus for monitoring and controlling the operation of a refrigeration unit

Life of this patent

Abstract

Claims30