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.
Claims22
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:
- 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;
- generating a present time stamp in the central controller;
- calculating, via a motor thermal model, a current thermal memory value for each of the overload relays based on a last stored thermal memory value and a time duration between the present time stamp and a stored time stamp;
- 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;
- removing power from a motor;
- generating a new time stamp;
- calculating, via the motor thermal model, a new thermal memory value for each of the overload relays based on the current thermal memory value and a time duration between the new time stamp and the stored time stamp;
- 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
- central controller has a clock and a timestamp generator for a thermal model;
- and
- the overload relays have no clock function for a motor thermal model.
A central controller for motor thermal memory value management of a plurality of overload relays in a motor control group, the central controller in communication with the plurality of overload relays which are individually paired with each of a plurality of motors or motor functions within the motor control group, the central controller comprising a source of time information and wherein the central controller is configured to:
- generate a present time stamp;
- calculate, via a motor thermal model, a current thermal memory value for each of the overload relays based on a last stored thermal memory value and a time duration between the present time stamp and a stored time stamp;
- pair the current thermal memory value to the present time stamp and store the paired current thermal memory value and the present time stamp in a nonvolatile memory;
- remove power from a motor;
- generate a new time stamp;
- calculate, via the motor thermal model, a new thermal memory value for each of the overload relays based on the current thermal memory value and a time duration between the new time stamp and the stored time stamp;
- and
- restart the motor according to the new thermal memory value.
A central controller for operating a plurality of overload relays, each associated with a motor in a motor control group, the central controller comprising:
- a clock providing timing functions for each of the plurality of overload relays;
- a timestamp generator associated with the clock for generating timestamps,
- wherein the central controller is configured to calculate, via a motor thermal model, a thermal memory value for each of the plurality of overload relays, each thermal memory value being paired with an associated timestamp;
- the central controller further comprising a nonvolatile memory for storing each calculated thermal memory value and its paired timestamp,
- wherein the central controller is further configured to start or restart motors of the motor control group according to their latest thermal memory value.
Dependencies are inferred from the claim text.