| 摘要 |
PROBLEM TO BE SOLVED: To solve such a problem of a conventional freezing preventive device of a pump that the number of components increases because it is required to provide a temperature detector in a motor and an inverter, respectively, and to continue water supply stably with a simple structure.SOLUTION: An inverter 30 for controlling a synchronous motor 20 for rotary driving a pump section 10 is configured to warm the motor by feeding a reactive current, when the temperature of a housing constituting the outer periphery of the armature of the synchronous motor goes below a first predetermined temperature, i.e., a temperature determination value for starting to feed a reactive current to the synchronous motor, and to output a signal for turning the power of a heater on when the housing temperature goes below a second predetermined temperature, i.e., a temperature determination value for starting operation of heaters 61, 62 provided at the end of the pump section. Consequently, a motor in low temperature state is heated and demagnetization is prevented, and demagnetization and step-out of the motor due to freezing in the pump section are prevented, resulting in stabilized water supply. |
