Method and apparatus for preventing motor over temperature for a window closure system

A control system and method predicts the occurrence of elevated temperatures in an electric motor 12 used to operate a window closure system. The motor 12 includes an output 14 that is operably coupled to a window component 16. A controller 20 monitors at least one motor characteristic, such as motor activation occurrence or duration of activation, over a period of time and generates an output signal 22. The controller 20 prohibits operation of the motor 12 when the output signal 22 exceeds a predetermined limit.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT An electric motor control system for a window closure application is shown generally at 10 in FIG. 1 . The control system 10 includes an electric motor 12 having an output member 14 that is coupled to drive a window component 16 . The motor 12 drives the output member 14 , as is known in the art, to move the window 16 been various operational positions. The motor 12 is operably connected to a controller 20 that monitors at least one motor characteristic. The controller 20 monitors and/or measures the motor characteristic over a period of time and generates an output signal 22 based on the information collected during monitoring and measurement. The output signal 22 is compared to a predetermined limit and if the predetermined limit is exceeded the controller 20 prohibits further operation of the motor for a predetermined length of time. The predetermined length of time can vary depending upon application, however, the length of time should be sufficient to allow the motor 12 to cool to an acceptable operational temperature. The controller 20 can monitor any of various motor characteristics either alone or in combination with each other over a predetermined period of time prior to generating the output signal 22 . Preferably, the controller 20 counts the number of motor activations that occur during a period of time. The predetermined limit can then be set to a predetermined number of activations per predetermined period of time ratio. This ratio can vary depending on the type of window closure being moved. If the ratio is exceeded then further operation of the motor is prevented. The controller 20 can also measure the duration of each activation cycle. For example, the controller can measure that a first activation cycle lasts five seconds, a second activation cycle lasts 2 seconds, a third activation cycle lasts ten seconds, etc. The controller 20 then takes into account the number and duration of motor activations and compares this to a predetermined limit to predict potential over-heating within the motor. The controller 20 can also measure the duration of rest time between cycles, i.e., the period of time that the motor 12 is not activated. The controller then takes into account the number and duration of motor activations and the rest periods and compares this to a predetermined limit to predict potential overheating. The subject control system 10 provides a simplified method and apparatus for predicting occurrence of over-heating conditions in an electric motor for a window closure system. One of the benefits with the subject invention is that further operation of the motor can be prohibited before the elevated temperatures are actually experienced by the motor components, resulting in reduced wear and tear on the components. Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.