Frequent start protection and economizer control for a motor starter

摘要

A motor starter control is disclosed in which an ambient temperature sensor (36) is positioned to sense ambient temperature and pole temperature sensors (30, 32, 34) are used to sense each pole temperature in a motor starter (12). A microprocessor (28) is connected to periodically receive (72, 122) the temperature signals and monitor change in operating temperature of a motor starter system. The microprocessor models cool down characteristics of the motor starter system (76, 78, 80) and compares currently acquired ambient and pole temperature signals to the modeled cool down characteristics (82) and determines whether the motor starter system is cooled to a safe start temperature (84, 92). The control ensures that a maximum number of starts per hour is not exceeded (96) and prevents attempted starts that not only waste energy, but further prolong time to a successful start.