Centralized motor thermal memory management
AssigneeSchneider Electric USA, Inc.
InventorsKevin M. Jefferies, Benjamin W. Edwards
Life of this patent
Estimating the term…
Abstract
The overload relay units within a motor control group have the timing function for their motor thermal memories under the control of a central controller in communication with the overload relays. Thus expensive timing components and control of timestamps can be removed from individual overload relays. Further reduction of individual overload relay components can be accomplished by removing the nonvolatile memory function from the individual overload relays and allowing the central controller to perform the nonvolatile memory functions for the overload relays. The motor thermal model function for the overload relays can remain in the overload relays or might be moved to the central controller if communication bandwidth permits.
Claims4
A method of operating a central controller for motor thermal memory value management of a plurality of overload relays in a motor control group, comprising:
- a) installing a central controller which includes a source of time information and placing the central controller in communication with a plurality of overload relays which are individually paired with each of a plurality of motors or motor functions within the motor control group;
- b) generating a present time stamp in the central controller;
- c) calculating a current thermal memory value for each of the overload relays based on the time duration between the present timestamp and the stored timestamp and the thermal memory value pair;
- d) pairing the current thermal memory value to the present time stamp and storing the paired current thermal memory value and the present time stamp in a nonvolatile memory;
- e) removing power from the motor;
- and
- f) generating a new time stamp, calculating a new thermal memory value,
- and restarting the motor according to the new thermal memory value.
A motor control group including a plurality of overload relays for at least one motor, and a central controller in communication with each overload relay;
- wherein the
- a) central controller has a clock and a timestamp generator;
- b) the overload relays have no clock function for a motor thermal model.
Dependencies are inferred from the claim text.